DiyLightAnimation
Hardware => Lynx Express => Topic started by: spider236 on December 18, 2010,
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i assembled the express board and tested it by plugging it in prior to installing the chips and both the 5 volt and 3.3 volt green leds lit. at that point it appeared the build was going well.
i installed the chips, hooked up 2 power cords and plugged them in. i do not get a PRG code on the leds. they dont light at all. when i press the mode button, nothing happens.
there is one led (#6) that always has a faint glow to it when the board is powered up. i can see no bridge on any solder joints, so im not sure why its doing that. if i press RESET, it goes out, then comes back on when i release the button.
if i press the SELECT button, led #16 lights up, then goes out when i release it.
the board will power up when the left side ac cord is the only one attached. it will not power up when the right side ac cord is the only one attached.
the board is terminated.
i dont know whats wrong.
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Was the pic programmed and with the correct firmware?
Are the Seven Segment LED display in correctly?
Remove the large chip to the right of them and check the pins
Did you miss a small capacitor?
Rick R.
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i assembled the express board and tested it by plugging it in prior to installing the chips and both the 5 volt and 3.3 volt green leds lit. at that point it appeared the build was going well.
This is good
i installed the chips, hooked up 2 power cords and plugged them in. i do not get a PRG code on the leds. they dont light at all. when i press the mode button, nothing happens.
Not so much need to post some pictures for us.
there is one led (#6) that always has a faint glow to it when the board is powered up. i can see no bridge on any solder joints, so im not sure why its doing that. if i press RESET, it goes out, then comes back on when i release the button.
This sounds like a firmware load issue
if i press the SELECT button, led #16 lights up, then goes out when i release it
It should so this is normal
the board will power up when the left side ac cord is the only one attached. it will not power up when the right side ac cord is the only one attached.
also normal
the board is terminated.
i dont know whats wrong.
Thats Ok we will get it working.
RJ
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shouldnt the numeric leds light up when the board is powered up, or does all the firmware need to be installed as well? ??? how can i install firmware if the board itself has issues? i cant get it to go into program mode.
my dongle now has a red led lit. it did have a green led lit. does that mean i need to reinstall the firmware for it as well?
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Was the pic programmed and with the correct firmware?
Are the Seven Segment LED display in correctly?
Remove the large chip to the right of them and check the pins
Did you miss a small capacitor?
Rick R.
the pic on the express is not yet programmed
the numeric leds are installed correctly
i removed the large chip; no pin issues.
all caps are installed.
i will post a picture asap.
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Here are some pictures of the board:
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The Pic will need to be programmed before the displays will work.
Assuming you are using a picKit to program it. With the board powered off, connect the pickit to the 6 pin header on the express (be sure to match the arrow to pin 1) and download the correct hex file to it. The pickit can supply the power needed to do this. Then remove the pickit, repower your express and report back to us.
-Jeff
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Yes if the pic is not programmed then what you have described is totally normal. Program the current firmware in the pic and things will change for the better.
RJ
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The Pic will need to be programmed before the displays will work.
Assuming you are using a picKit to program it. With the board powered off, connect the pickit to the 6 pin header on the express (be sure to match the arrow to pin 1) and download the correct hex file to it. The pickit can supply the power needed to do this. Then remove the pickit, repower your express and report back to us.
-Jeff
i downloaded the lynx express firmware lnt from the wiki page via the pickit 2 to the pic, repowered unit - no change. now what? ???
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Did you get the firmware from the correct location? Reason I ask is you created a new post which makes it hard to follow whats going on.
After you get the firmware you need to start up pickit2 software and then load the firmware and write it to the pic
Once that is done remove the pickit from the LE and power up the LE
Rick R.
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yes. i did that, but i still cant get the board to go into program mode.
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Ok,
Let me explain, we are not able to see what you are doing and what is happening. This requires you to give us much more info so we understand what is happening to help.
So answer some questions so we understand.
You posted that your display was not working and do to some good questions from rick we found out you had not loaded your firmware.
So now you say you have loaded the firmware. Did it verify OK ?
When you turn on the express now do you get the led displaying anything or is it still blank?
The leds for power both 3.3 and 5 volt are on correct?
When you say you can not get it to go into program mode what do you mean you can not? What are you doing to get there? what are you seeing when you do it?
Why are you trying to go to program mode? It would be best to test it first as the firmware is set to channel #1 and the Default curves are loaded. The unit should work as it is.
Remember we do not have the info you do about the issue.
Biggest thing is to not worry we will get you going with enough information.
RJ
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problem solved. :)
initially what i did was open the pickit2 software, clicked "file" > "import hex" > selected the hex file > downloaded it > the pickit2 software said "download successful". i could see the hex code changes in the "program memory" window. it looked like the file loaded successfully, just as the software message window indicated, however i could not get it to "verify". i started clicking buttons, and when i clicked on the "write" button, the program loaded the pic AND would then verify it. not sure what happens, but it looks like the first "downloaded successfully" message means the software was successfully downloaded to the pickit2 software making it available for download to the pic itself. so, to make a long story short, you gotta click the "write" button to get the pic to load. didnt know that.
thank you all for your help with this.
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Yep!
Thats why I asked if it verified.
It does tell you the import of the firmware is successful but you do need to hit write to load it into the pic chip. I hope you are working now.
If not please let us know how to help.
RJ
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i just found the instructions for flashing the pic in the express manual. some how i missed that. <fp. sorry.
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No one would have said anything about it being in the instructions if you had not. Were not "That" kind of group. We just want you to be successful.
RJ
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RTFM!!! (Read The Full Manual)... ;)
<la..
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Ok, I'm having a similar problem with my twelvfth Express. Built the unit, power test - good lights on 3.3v and 5v leds. Installed the chips, wired it up. I installed a PIC plugged in: 3.3V led and 5V led lit. LED #5 lit as well.
I had this problem in previous builds. I unplugged, attached myPickit2, powered up, Ran PICkit 2 v2.61, erased the memory on the PIC, Black Check. Loaded LE_Firmware_09_2010.hex, Write to PIC, Verify. All ok. (I know I'm doing this right because I did it the same way for my eleventh build 2 minutes earlier).
I remove the Pickit2, repower and I get the following:
3.3v led lit, 5v led lit. No startup message. LED display numerals are blank.
I power down, remove the numeral displays and the adjacent chip. Verify pins not bent and reinstall. I remove the board from the case, flip, and painstakingly check every solder joing for bridging or poor contact with the board. No obvious problems.
At this point, I'm open to suggestions... anyone?
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Greetings,,,
If the 11th built one is right there, can you substitute the chips, one by one, to double check, starting with the pics and the led drivers?
Keith
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Good idea... trying now.
I did try replacing the PIC so I know it isn't that, but I'm going to run through the others and see if it gets me anywhere.
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Ok. Replaced each of the numeral displays and the display chip one at a time with no result. Also replaced the PIC without success. I placed each of these removed items in board 11 and tha board still worked fine. Do any of the other chips impact on this aspect. I can certainly do them all, but if it isn't relevant I'd rather not risk bending up all the prongs removing and inserting them.
I did have some trouble soldering the Triacs on this board (board 12). The center pole of each just would not blend, even at 380 degrees. I finally got connection (I think) on each one, but they are messy. There is no bridging at these joints, but there may be a 'layover' or whatever you call it when you get a good sized blob of solder that looks like a clean pyramid, but in reality is just 'laying' on the board rather than fuzed to it. I wouldn't think that the Triac connection would matter to the booting of the hardware, only with the actuation of actual current to the channels, but if I'm wrong on that score, someone let me know and I'll go back an redo all those joints. Again, just don't want to be chasing straws that aren't relevant to the problem at hand.
Thanks again for any help.
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Greetings,,,
Just for grins, can you check the H11AA1 chip, below the transformer?
Then, it might help if you can show pics.
Keith
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No luck with the 'just for laughs' chip. Works fine in board 11 as well. Pics attached.
...man, I love the troubleshooting part of this hobby. :)
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Greetings,,,
Ok. Can you check the push buttons, just to make sure they are not physically sticking?
Troubleshooting is where the fun begins.... lol...
Keith
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Buttons appear ok. They are in the 'out' position, springs working normally. Obviously I can't be sure about the internals, but they appear fine.
Just for more grins, I switched out the two RS485 Chips at either end of the Cat5 connectors with no change in results.
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Greetings,,
Can you put a DMX signal into it, and try all channels on? See if it picks up and turns on the leds? To try to see if that's working at all, or just a readout issue?
Keith
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Hello
I would also look at cold solder joints/ bridging. I'm no expert by any means but What I have found is to use a good hot soldering Iron (500F). Getting on the joint hold for 3 seconds then get off in that time you should see the solder flow. A cold iron can lift traces by overheating them by holding your iron to long. The outher thing I like doing is to use machine sockets for the Ic's (chips). Can be a pain installing them, but I also inspect my solder joints with a lighted magnifying glass.
Jess
Oh, I also use flux cleaner. From my understanding it will conduct current.
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No dice.
I hooked up and did both an all channel test and a sequence test, again using board 11 as a control. I got LED's and power output on board 11 and nothing on board 12. I checked for leds on the board to go on as well as actual power at the outlets... nada. I did verify that the terminator was on (jumped) on both boards. I assumed the board 12 would default to channel 1, but checked for the whole 128 channels on my sequence profile just in case... again, nada.
Think I'm calling it for tonight, maybe something will come to me in the morning... or maybe something heavy will fall on the board and I won't have to worry about this one... I really appreciate all the ideas though. Keep them coming if you have any more and I'll be back running through it again soon.
So far I figure we've effectively eliminated the LED numerals, the specialty chips, I know all the resistors and parts are in the right place, the PIC is good (or at least I've tried a good PIC in the board. The LEDs are all directionally correct. I've double checked the soldering and with the exception of the Triacs it's up to my normally successful (if mediocre) standards.
Could it be a faulty socket... and if so, how would I check?
I did notice that the decimal on the first (far left) numeral is glowing very faintly. It's a constant on and was probably there from the begining and I just didn't see it. It hasn't moved or changed with any of the tests. No other illumination at all in the numerals.
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On the soldering....
I've never soldered over 390 degrees. I'm sure the chip sockets, resistors, connectors, et al are good. I get good flow at 350-375 for those and have checked them all for clean adhesion and bridging. (What looks like bridging in the upper left of my pic on the chip that governs the LED numerals is actually glare.). My Triac, transformer, and fuse joints are always a bit iffy. I up the temp to 390 on those and have a tough time as the heat seems to bleed out into the rest of the available metal and it takes me a bit to get a good seam. I feel good about everything on this board except the triacs at this point.
Can anyone tell me, is it possible that a non-joint in a triac would prevent a proper system boot? It's on my list to go back and redo all 48 of those joints just to be safe... I'm a bit leary of upping the temp to much more.... I was considering trying it at 410 or 415 but 500 YIPES!
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Greetings,,,
You said the 5 and 3.3 leds are on, correct? I'd pull out the row of 16 chips to see if there is a problem of some type there. And I'd also first pull out the 11th LE, so that there's no issue there with the terminator.
I'd also do the full 512 channel output on Vixen, or one of the testing softwares, to insure you're hitting the 16 channels on the LE. Can't be certain where the start channel is.
Keith
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Just for laughs I went and looked at my Iron it's hotter then 500F. Do me a favor find a junker board and crank the iron. Don't camp you might be supprised. A radio tec taught me this.
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try to get another pic of the bottom (where you solder) of the board. without a glare from the board. maybe at a 45 degree angle so we can see the soldering a little better.
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Ok. I pulled and replaced the 16 chips above the heat sink with no resuts. I'm resoldering the triacs at a higher temp to ensure a clean bond this afternoon. Once that's done (and assuming I haven't corrected the problem) I'll try and get a few pics of the back of the board without so much glare on them.
Thanks for all the suggestions so far.
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The issue will have nothing to do with the triacs or optos. You are looking for an issue in either power, the pic or the display chip and it little 2700pf capacitor.
Post good pictures of the of the bottom and we will see if we can see anything.
RJ
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I've replaced both the PIC and the display chip with ones from a fully functioning board yielding no results. (I also placed the chips taken from the problem board in that other unit and it works fine). From this I'm concluding that the chips themselves are out as the source of the problem - correct me if I've missed something there.
I'm attaching pics of the relevant portions of the back of the problem board for comment. These are shots of the display area and of the PIC area. I have to believe something is wrong here, that or the sockets themselves are bad (or were damaged during my install), though I can't see any obvious issues.
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I keep seeing something that looks like a short on the LED? connection just to the left of the camera flash flare in the first picture. It seems to be there in other pics also.
Maybe a short on the LED? connection above the camera flash flare on pic two also.
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Here's a few additional random shots of the board from both front and rear. I've removed the display modules, display chip and PIC to show the socket condition. Can anyone spot anything amiss?
This one really has me stumped.
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And a final two more.
...checking for the short noted above.... not seeing anything. Does it still appear in the new photos?
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The 485 chip near the large cap is in backwards- maybe - sure looks like it!! It is a 485 chip (photo is too blurry there but I think I see the ST logo so it should be).
Can't tell if the short is there or not from the last pics.
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Good call Kirk. It looks that way to me also.
Ron
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That may not be the problem, in the first photos it is installed correctly.
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Good call Gforman. It looks that way to me also. <yk..
Ron
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Have you looked inside each of the sockets to be sure there are no solder bridges? I have seen where solder will run down the leg and inside the socket.
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I'm a little concerned about the solder joints on the two marked resistors (the 15K ones near the transformer). It does not look like the solder flowed through the board. I am also a little concerned about the solder joints on the back of the big capacitor.
I prefer to work with a really hot iron and move fast - as soon as the solder metls and flows, it's time to move on. Usually ~3 seconds or less per joint for the small stuff: resistors, capacitors, sockets, and such. If you have to keep the iron in place for more than 10 seconds for the solder to melt, it's either not hot enough, not stong enough (wattage), or you are working a heavy joint - like the spade lugs on the MR-16 or the fuse socket...
One other thought, if you have a multimeter, you may want to check the 3.3 and 5 volt regulators to make sure you didn't swap them. They look a lot alike and you really cannot tell once the heat sink is attached.
Good luck!!
RM
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Push the reset button in and hold it. Then power up the board. If it works with the buttonheld in you have the reset button backwards.
RJ
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Add on to my previous message - if you do start probing around with a multimeter, please be very careful. There is live 120VAC on that end of the board!!
RM
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It looks to me like your 485 chip is in backwards. Pin 1 the one with the circle, should be facing the top of the board.
EDIT - Nevermind. Day late and a dollar short. Looks like everyone else caught that too.
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I touched up the solder joints for the 15K resistors and the 4700uf. I also tried the 'hold the reset' without effect. I examined the reset (and other buttons closely, and they are all in the right way. My daughter was looking at it next to my functioning board and noted that the center resistor next to the 3.3 and 5v lights do not match between the boards. My other boards all have a wide brown, thin blue, thin brown, thin gold stripe. The problem board has a Wide brown, wide grey, wide brown, wide gold pattern. All the other resistors on the board appear correct. Is there a chance I have the wrong resistor for this application or is it just a matter of different manufacturers?
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At a more complete look... all the 180 resistors are the new pattern on board 12, so I believe it's just a manufacturing difference (unless they are all wrong!?!). I looked as closely as I could for any 'bridging' inside the sockets and didn't really see anything amiss, though I'm not sure what exactly I would find if it were 'bridged' in there.
I am also in joyous receipt of 4 more Lynx express kits today compliments of the J team in FL (Thanks guys), so I now have spare parts galore if it's time to start pulling and replacing things on board 12. I'm not (yet) an electronics guru, so testing via DVOM etc is beyond my current knowledge level... and I wouldn't know what I was looking for anyway... so I ask:
Is it time to start pulling and replacing components? If so, what's the best order to move in? I don't mind buying a few replacement parts if necessary, I just am really reluctant to scrap the whole board. Given that the chips all work in board 11, I have to believe it's either my error, or a minor component failure.
Thanks also to everyone who's offered suggestions so far. I didn't mean to tie up so much collective brainpower on my piddly problem. I'm at a loss here and I really do appreciate all the help.
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Greetings,,,
Can you double check, in case I missed it, and see if you have triacs in all 16 locations, and not a switched regulator in one of those locations, just in case?
Keith
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I checked and all 16 are triacs. I aslo pulled both heat sinks and physically checked the regulators to verify that they were in the right slots, and that I didn't get accidentally shipped 17 triacs or another kind of regulator - LD33CV in the lower and the 78s05 in the upper.
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Did you ever go back and reflow the solder connections on the PIC socket? There is nothing obvious that I see from the pictures but the board certainly is acting brain dead and you KNOW the PIC is ok from swaping.
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I did reflow the connections at the PIC and at the numeral control chip. Since we know the chips and numerals themselves are functional, that seems to leave the sockets themselves, or the power supply to either the PIC or the Numeral chip. I've been trying to trace the board (and in way over my head here) but it seems to me that the power to the PIC is 3.3 V coming in via the reset button, and that power to the numeral chip is 5V coming via the R485 chip next to the DMX in. 5.5V is then supplied as required to the LED screens via the numeral chip.
We know via the working leds that we have good voltage at both the 3.3V and 5V origins (do we?) so the problem ought to lie between the LED lights after the regulators and the two chips. Does this make sense or am I stabbing wildy in the dark? Everything from the AC input to the regulators should be out of the diagonstic loop, and everything from the PIC downstream through the channel LEDs to the output sockets should also be irrelivant at this point.
I confess that trying to follow the board through the PIC and numeral chip is losing me so I can't tell which of the resistors at the top of the board are in the pattern or which of the 1ufs or the 2700pf could be factors as well. Am I wrong at this point in excluding the power tranformation/regulation, and output streams from consideration?
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I didn't replace the fuses, but removing the left fuse from the board results in no power at all. With the fuse in, I get good LED's at the 3.3 and 5 V regulators. I think this rules that out.
Could a bad fuse, or more likely a bad or partial solder joint at the fuse holder causing irregular AC result in a constant green LED at the regulator but still create a problem further downstream?
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From the way it looks, I doubt it.
Just so we're all on the same page, and just to make sure of the symptoms:
Can you redescribe what happens when you power up the board (what lights up, etc)?
Also, can you list all of the steps you have taken thus far (since programming the pic)?
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Resistors - The width of the stripe doesn't matter. If I remember my color codes correctly Brown-Blue-Brown is 160 ohms while Brown-Grey-Brown is 180 ohms. That particular one is used to limit the current to the LED, so 20 ohms is not going to make or break the system. Gold is the tolerance, I think its 5%.
RM
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According to the Express wiki page, if you have 3.3v and 5v lights on before installing the chips, everything with the board is good.
It sounds like you've replaced all of the chips with chips from another express. You don't have a multimeter so we can't read voltages or currents across resistors or caps.
Could it be a short across pins on one of the chip sockets on the top side of the board (rather than the underside, which is easier to see)?
Reflowing would also make a short like this worse.
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Here's the board's behavior to date:
When I was building the board I conducted the recommended power up test prior to installing the chips and final wiring.
When I plugged it in at that time, both the 3.3V and 5V LEDs came on and stayed lit.
After installing the chips and wiring I then plugged the board back in. The 3.3V and 5V LEDs come on and stay on. The LED from Channel 5 also came on, and there was no activity on the LED numerals. I had experienced this problem on a prior build and knew that the PIC needed reflashing (that solved the problem in the earlier instance).
I pulled the PIC and reflashed it and another PIC using a Pickit 2 and the current firmware.
The PIC I placed back in my board 11 worked fine after the reflash.
I placed the flashed PIC in board 12 and plugged it in. The 3.3V and 5V lights came on, no other LED's illuminated, but there is no activity at all on the LED numeral readouts (other than a very very faint light in the far left numeral screens decimal point).
I have since replaced every chip on the board with chips from a working board and continue to get the same results. The chips I removed from the problem board I installed in the working board and they function fine (so the chips are good, and the problem board is not frying anything).
I have also revisited the solder joints on the entire board a couple of times without luck.
I hooked up the problem board to my laptop and ran a channel check accross all 512 channels of DMX with no output from any of the 16 sockets on the board so there it appears to be more than just the display aspect.
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I beleive I do have a multimeter lying around (I was an amatuer electrician in a former life... just have never applied it in instances less than 120V AC or wiring less than 14 gauge). If someone can let me know where to stab and what equals a pass or fail reading, I can start working that.
There are no obvious front side shorts on any of the resistors but I can't really see the socket pins on the front end. Is there a way to check this effectively without removing the sockets and redoing?
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Do you have a friend who knows how to use a multimeter/DVOM? The actual power levels could be at play like a bad 3.3V (it has happened before). You should get 3.3V at the PIC on the pin you traced from the regulator.
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I beleive I do have a multimeter lying around (I was an amatuer electrician in a former life... just have never applied it in instances less than 120V AC or wiring less than 14 gauge). If someone can let me know where to stab and what equals a pass or fail reading, I can start working that.
There are no obvious front side shorts on any of the resistors but I can't really see the socket pins on the front end. Is there a way to check this effectively without removing the sockets and redoing?
Without the board being powered up, you could check ohms of resistance. In theory, there should be negligible resistance between shorted socket pins and infiite resistance between ones that are not shorted (unless they are shorted intentionally by a PCB trace).
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This is a long shot from looking at your pictures and also trying to simulate your problem on a LE.
I think your reset switch is bad or in backwards. Your last pictures of your solder side does not have the alignment pin in the hole.
If the reset switch is held down then powered up, nothing happens to the display as you described. So i think it is one or the other.
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To check voltages:
You need to set DC voltage reading on the meter. If your meter is not autoranging put the meter on DC 20V (or something close above 3.3).
Looking at the top of the board with the logo on the board readable that puts pin 1 on the upper left corner of the PIC. Place put your RED lead on the top right pin (28) and the black lead on the pin just below that (pin 27) and it should read 3.3v powered up obviously. PLEASE BE CAREFUL AROUND THE exposed 120V (as you know as an amature electrician)!!
If you want to test the meter, get a fresh 1.5V battery and see if it reads 1.5V when you put the red on the top of the battery (the end with the nub) and the black on the bottom.
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Ok, I have 3.3V at pins 27 - 28 conducting the test described by the Captain (Damn it Jim... I'm a visionary Christmas display artist... not an electrical engineer!)
That seems to rule out the bad reset switch (which sucks... cause that sounded like a really good... and solvable... problem)
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Ok, I have 3.3V at pins 27 - 28 conducting the test described by the Captain (Damn it Jim... I'm a visionary Christmas display artist... not an electrical engineer!)
That seems to rule out the bad reset switch (which sucks... cause that sounded like a really good... and solvable... problem)
Did you do the test that RJ suggested of holding down the reset switch and powering up the board
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I did conduct the reset test. unplug board. press and hold reset as I plug in board. Maintain hold on reset button. No change. Release reset. No change.
I examined the reset switch closely. The spring operates normally. It stays in the 'up' or 'out' position when released, there is no visible or audible sign of damage to it, and I have verified that it is oriented properly with the plastic 'pin' on one end in the corresponding hole on the board.
Can anyone tell me where to test for 5V? I checked voltage at the LED indicators and get about 2V at both the 3.3V and 5V light... I figure this is normal... just don't know what to stab looking for 5V and don't want to fry anything.
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Unplug the board set your meter for continuity, and check for continuity between the lower right side of the reset switch and the lower left side when the reset is pushed (from the top of the board, not the underside).
While you're at it, perform a continuity test on the lower right post and the lower middle post of the select and mode switches. Check both for depressed and not depressed. (again from the top side of the board).
If your meter doesn't do continuity, then do resistance. There should be almost 0 resistance when there is a connection.
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For giggles I tried the resistance test suggested. I unplugged the board, flipped it to the solder side and tested adjacent pins on the PIC all the way up one side and down the other. I got varying readings from 0 Ohms to infinite resistance including 2 Ohms, 4 Ohms, 10 Ohms, and 18 Ohms. I suspect the board circuitry and whatever magic is going on inside the PIC are affecting this to the point of it being unhelpful.
...sounded good to me in theroy though.
On the reset button:
I do not have continuity, but using the Ohm meter I tested the reset at the lower right and lower left. In the 'rest' position I get infinite resistance, when depressed I get zero resistance
On both the mode and select switch using the center and right bottom posts I get zero resistance in the 'rest' position and infinite resistance when depressed.
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The pic itself needed to be removed for that first test to work.
As for the test of the select and mode switches...my bad. It should have been lower middle and lower left (from the top of the board).
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Ok... something interesting to report:
I re-did the mode and select switch tests and got the expected results. zero resistance when depreseed, infinite in 'rest' position.
I pulled the PIC and did the resistance accross the adjacent pins and got infinite resistance in all pairs except the following:
5 Ohms pins 23 - 22
8 Ohms pins 12 -13
0 Ohms pins 1 -2
Does that mean anything to anyone?
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Wait wait.... board was facing backwards:
infinite resistance pins 27- 28
8 Ohms pins 17-16
5 Ohms pins 7-8
probably not as interesting now... but still Greek to me. :)
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Ok pin 7 and 8 is 5 ohms I would be very carefull here even though the pic is out other things in the circuit can cause the low resistance on the two pins. Looking at a data sheet on the pic pin 8 is VSS or power to the chip 3.3 VDC and pin 7 is a data line. personaly I don't like doing resistance (ohms) testing to many other things play into the results. power the board leave the pic out check voltages on the same two pins. if they are shorted then you will see 3.3 v on pin 7 . I would strongly urge you to compare your results with a known good board with the same setup (pic in or pic out). You have a very good map in you other boards.
Jess
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Ok, I have 3.3V at pins 27 - 28 conducting the test described by the Captain (Damn it Jim... I'm a visionary Christmas display artist... not an electrical engineer!)
That seems to rule out the bad reset switch (which sucks... cause that sounded like a really good... and solvable... problem)
If the pic has 3.3v on these pins you know power is good on 3.3 v
Now make sure that pin #1 on the pic is at 3.3v + so it is no in reset.
Then we need to check the 5v section on the led setup.
I do not have the information with me as I am out of town but once I get back I can tell you where to check on the display chip.
RJ
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On the led driver (the big chip) pin 13 is ground (black lead on meter) and 14 is power. Looking at the chip as it is oriented on the board (on its side), pin 1 is lower left, 13 is lower right and pin 14 just above it. I think RJ is saying that should be 5v. The datasheet linked from Mouser says it should be 5v also...
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Greetings,,,
You could also check with a known good unit and compare readings with this unit, side by side.
Keith
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I tested the LED driver per Cpt Kirk and get a good 5V accross pins 13 and 14. I tested the PIC at 27 and 28 again and get about 3.8V. I tried to test PIN 1 on the PIC using pin 27 as the ground and I get about 3.0V not 3.3 Do I need to use another location as the ground for this test or is it possible I've found a potential problem area?
I basically took a mental health break from this board this afternoon and assembled one of the new boards (board 13) from the recent COOP. Full functionality first try on that one so I know I haven't lost my mind completely. I'm now back on the problem child (board 12). I'm going to lay the two boards side by side and do the ohm resistance tests from earlier on each with the PIC removed. I'm not entirely confident of what the specific readings will mean, but if they differ between the two units I will note where I find it. I'm doing this with power removed (obviously) as I don't want to go poking various things without quite knowing what I'm doing. I can't believe shooting 120V AC through the LED driver on accident would do anything to help my cause here.
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I hope the 3.8 was a typo as that is very high for a 3.3 volt device. 3.0 does not sound right for pin 1 (but I am not measuring my working board). Could you check that same Pin 1 voltage on one of your working boards?
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Pin 27 is 3.3v pin 28 is ground pin 1 is reset so when the reset switch is pushed, pin 1 goes from 3.3v to 0 volts
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Pin 27 is 3.3v pin 28 is ground pin 1 is reset so when the reset switch is pushed, pin 1 goes from 3.3v to 0 volts
No the pin#1 should be about 3v all the time.
RJ
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I tested the PIC at 27 and 28 again and get about 3.8V. I tried to test PIN 1 on the PIC using pin 27 as the ground and I get about 3.0V not 3.3 Do I need to use another location as the ground for this test or is it possible I've found a potential problem area? Sorry about this mybe some day somebody can teasch me how to do quotes.
I beleave you have found the problem. pin 27 is the power input and pin 1 is lets just for now call it a reset and it has nothing to do with the design of this board except for in board pic programing. Both pin 1 and pin 27 should be 3.3 volts all the time. ( thank you RJ) I think if you test this again using pin 1 plus side of your meter and pin 27 as your ground side of the meter then you should read about -3.3 volts. Some where pin 1 and or the circuit board trace is shorted to or close to ground pulling pin 1 close to ground causing the pic into a reset condition and I beleave that this would cause all the symtoms your having.
Now at the risk of passing on bad habaits take pin 1 of your pic bend out the pin just enouth so when you reseat the pic it will be out side of the socket. your board should run now
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Real quick, circuit functioning properly measuring pin1 to pin 27 you should read o volts. If this is all true then I think your short is under the programing header plug. Pin 1 of the pic is tied to pin 1 of the programming header and pin two of the programing header is ground, wow. If I'm looking at the pictures correctly the trace goes from the programming header to pic pin 1. So the second place the short can be is under pic socket at pin 1. Secont bad habit...... I have done this allot on acid damage board repairs. If you are very carefully pry up the plastic working slowly all the way around you can reveal the tops of the pins/ board. Clear the short and replace the plastic housing or solder in a new socket.
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Tried the "Pin 1 out" solution described by Jess_her without change in the result. Board still acts the same under power with pin 1 removed from the socket.
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I have now also lain my freshly minted and functioning board 13 next to the problem child (board 12) and done a few meter tests on each with the following (disenheartening) results:
Board 12: Pin 27-28 3.8V
Board 13: Pin 27-28 3.8V
Board 12: Pin 1-27 3.0V
Board 13: Pin 1-27 3.0V
These appear to be functioning normally and suggest to me that the problem must lie elsewhere
All of these tests are being done on the top of the board, under power, with the PIC in place. I am stabbing the socket/pin junction where the PIC prongs meet the socket.
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What do you mearsure on the output of the 3.3 volt regulator?
Sounds like you might have a bad regulator?
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Not sure where to stab to measure that.
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Good morning,
Pin 27 on the pic is a power input to the pic so if pin 1 has 3.3 volts on it in normal operation then you would see 0 volts measuring from pin 1 to pin 27 on the pic. Can you measure from pin 1 to pin 28 on the pic? do you get 3.3 Volts here? IF you get 0 volts here then somthing is wrong the pic is in reset.
I really do believe your on the problem.
If you had it with this board I'll buy it from you at your cost, want a LE anyway.
Jess
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If Jess's test turns out correct, then it probably doesn't sound like the pic or the pic socket is the issue...but other experts in this can correct me if I'm wrong.
Also if you reprogrammed the pic while it was on the board, then it couldn't be the pic or the socket as it probably would have returned an error.
RJ said in previous posts to check the display, as well as the tiny capacitor...don't have the board in front of me...I think it was 2700pf.
Although I'm not sure of a good way to check the cap other than desoldering and replacing with a new one...as I said, I'm no expert. Just trying to help.
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Here are the actual voltages taken across the PIC pins.
27 and 28 - 3.8 volts
27 and 1 - 3.0 volts
28 and 1 - 0 volts
Everyone is going to have to excuse my lack of knowledge of DC based electrontics, but when you ask what the voltage on a pin is (ie What's the voltage at pin 1, or what's the voltage at the 3.3v regulator) I don't know how to test for that. I need two places to stab the meter. If it was a normal AC 120v circuit I'd stab the neutral bar... I figure if I do that here, I'll fry whatever I'm trying to test. I'm more than ready to post any readings anyone can think of that may help, but in all cases assume I'm an idiot and give me a place to stab each probe.
I'm ready to start removing and replacing components at this point... I have 3 more complete sets to assemble on hand, but obviously I don't want to try and desolder a 28 pin socket at random, so if we can narrow it down with some confidence I'll crank up the desoldering equipment.
Jess_her - I hate giving up on something so I'm not ready to throw in the towel just yet, and I need 14 functional Lynx expresses for my display (which means I want 15 on hand for the season). At present I only have 14 including the problem board, so I also want to make sure I can replace it before giving it away. On the other hand... too many more days of this and I'll probably be ready to give it up at a heck of a discout :)
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let me do some more research going on vacation tomorrow bee back next sunday
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I'd replace the cap first, then if that doesn't work, the LED display.
If the pic worked in one of the other boards, then it's not the pic itself.
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I'm wrong Pin 28 is power pin 27 is ground pin 1 is reset
so on the pic
pin 1 to pin 27 about 3 volts
pin 1 to pin 28 0 volts
I so wish I had a schematic of this board
So so sorry
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OK if any trust is left, Check the resistance of your volt meter leads (hold them together) to see if you have <1ohm. Check voltage on pin13 and pin12 of the SSA1046 display driver. Should be 5 volts if more than 5.5 we got problems. From Pin 12 to to pin 24 and pin 12 to pin 23 check voltage we should see something, These are the data lines to the display driver. Big guess here should see 1.5 to 3.5 volts. If it is close to 0 or 5 volts we got problems back at the pic. The 2700 cap, check from pin 12 to both sides of the cap 0 volts on one side and something on the other side which goes to pin 2 of the display driver. If you don't get anything here don't panic I'm just curious you may not have the right type of meter.
Let me know, I'm here for you buddy ;D
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I replaced the 2700pf cap with no results other than to learn that I REAAALLLLLY don't want to be replacing components unless pretty certain it'll solve the problem. I destroyed the old (and probably good) cap getting it out, almost scratched the daylights out of the boad trying to clear enough solder from the holes to get the new one in, almost destroyed the new one doing the same and finally got it connected, but only by seating it a mm or so into the board face and soldering it there
...and that was one 2 pin cap.... I can't imagine successfully replacing a 28 pin pic socket at this point. Not without hours and hours of practice and work anyway.
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Yea it can get tough with out the right tools. But there are some good ones reasonable. Me I like to use flushing side cutters and solder wick being carefull about not to much heat. ( staying on the board to long)
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Can you pm me and lets set up a time to meet in the teamspeak chat and I will help you troubleshoot it.
RJ
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No solution yet... Just taking the day off from solder fumes. If I ever figure is one out I'll post what it was and how it was found just so everyone will know should it come up again.
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Was this le part of the coop?
If it was you do not have to program the pic.
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Did you guys ever figure this one out? It would be good information on what exactly was wrong in case someone else runs into the same issue.
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I have not resolved this one yet but I will definitely come back and share what the problem was once I do. I put it aside for the last week or so to work on some other stuff and to be able to come back to it fresh (I was getting to the point where I was afraid I would just crack the board in half so I figured I'd best back off).
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I have the same problem as spider326, I tired to install the firmware and got the the following message:
Program operation of Program Memory Failed.
Address 0X0, read 0X0, expected 0X200.
I have attached a screen shot of the message.
This if for an Express 4. Is the firmware the same regardless of the version?
Any suggestions are greatly appreciated.
Danny
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Okay I was able to update the firmware. I did not choose the correct device in the drop down menu and I believe that was why I was getting the error message.
So the Mode and Select LED's are working but when I ran a test in Vixen no lights.
Here is what I have so far:
1. I have checked the com port settings and matched those to Vixen
2. I have the terminated jumper on. I am testing only one Express
3. The Wireless jumper is not on
4. I have tested the USB Dongle with another express to confirm it is working
5. This is an Express Version 4
Any suggestions are greatly appreciated.
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Okay I was able to update the firmware. I did not choose the correct device in the drop down menu and I believe that was why I was getting the error message.
So the Mode and Select LED's are working but when I ran a test in Vixen no lights.
Here is what I have so far:
1. I have checked the com port settings and matched those to Vixen
2. I have the terminated jumper on. I am testing only one Express
3. The Wireless jumper is not on
4. I have tested the USB Dongle with another express to confirm it is working
5. This is an Express Version 4
Any suggestions are greatly appreciated.
The wireless jumper says remove for wireless. You need it on and this should fix your issue.
RJ
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Hi RJ.
Correct. I put it on but still no lights. This is a board I recently put together and received the parts approximately 3 weeks ago. For the LE 4 is a jumper suppose to be installed from one of the legs of the 3.3 regulator to one of the legs of the 5.0 regulator? If so is there a picture of this connection?
Thanks!
Danny
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Not to start off. It was done to solve a cold temp issue. I have replacement 3.3 regulators that solve this with no modification to the pcb. I can send you them if you need them but the board will work as is until it gets in freezing conditions.
Can you post good close ups of the board so we can try to start fixing it.
RJ
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Hi RJ,
I did not have power to the right side of the board and the only channel I was testing was 16, so it didn't work because it didn't have any power. I have not installed all the power cords and all the channel cords because I do not have my case yet and just wanted to see if the unit was working to this point.
I moved the the test channel cord to 5 and it came on briefly but then began to flicker and then went out all together. Is this an indication of a bad solder joint? I checked all my joints with a light and magnifying glass and there are all reasonable except some of the triacs joints might be a little iffy.
Do you need power to both sides to run the express test? With just one power cord when I run the test the 16 LED's are barely lite when they chase.
Any ideas are greatly appreciated.
Thanks!
Danny
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It will work with only the left cord on but only channel 1 - 8 will have power.
Can you post good close ups of the board so we can try to start helping?
RJ
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Danny I responded to your PMs. I would check your solder joints very carefully on the triacs.
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Thanks RJ. Thanks Greg. All errors were my errors. Once I put power to both sides of the board the Express self test went fine and was I able to test the one channel I have connected in Vixen.
I need to pay better attention when reading the manual.
Thanks again!
Danny
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Glad it was easy
RJ
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