DiyLightAnimation
Hardware => Lynx Express => Topic started by: shgshgshgshg on June 23, 2012,
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Ok so I just got my pic programmed and the display is not showing me anything.
Other info, all three leds are on ( data, 5v, and 3.3v). Also when I press the select button the 16 channel led lights up. I have attempted to transmit the program from the configure utility and the first 2 leds light up and the rest flash very quickly.
My first thought was that I have some chips flipped the wrong way.
Thanks everyone, I'm sure it's a relatively simple problem, but I don't really know what to do from here.
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Sorry I accidentally posted twice. Also here is a pic of it attempting to be programmed...
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Check the 2700pF capacitor. From the manual:
Take the 2700pf cap. Find the location for this and install it. On some of these capacitors, the outer yellow epoxy is coating the top of the leads. Make sure that the yellow portion is not stuck inside the hole on the board; the part of the lead that goes into the hole must be silver. It is OK if the cap is not flush with the board when you install it.
If that cap isn't soldered correctly, the display won't work.
/mike
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Push and hold the reset button. Does the system act different?
Normally the cap issue that mike is pointing out leaves either two led digits working and not the middle or the middle and not the outer two.
RJ
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The cap is easy to damage when soldering. Don't ask how I know. I suggest ordering spares if you plan on building more LE's. Another suggestion would be to leave the cap sitting a little higher on the top side of the board and be fast to solder it. Don't leave the iron on it too long, but make sure the joints are shiny.
Good luck,
Greg
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Recheck the pic, I can't quite make out if it is in backwards or not. While you are at it, recheck the 485 chips as well, Heck recheck all them chips.. When you programed the pic, did you use a pickit 2 or 3? Did the checksum match with what was listed in the wiki? I have had problems programming the chip when using a laptop, Everythink checks out good, but the express refuses to work. Using a powered usb hub, or plugging in the express when programming seams to help.
Hope this helps.
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RJ - pushing and holding the reset button does not appear to change anything...
The 2700Pf is recessed pretty far away from the PCB. I wouldn't rule out the fact that it is blown due to heat though...
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Also I didn't do the pic programming myself I sent it off to be programmed, so I can't tell you of there were any issues there...
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I do not remember a case where the cap would make all digits be out. I am worried your pic is not really programmed. Can you post some good clear closeups of both sides of the pcb for us to look at. Sometimes we can see stuff you missed.
RJ
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Ok here are a bunch or picture I took. My phone is the only camera I have at te moment.. :/
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Last one...
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For now I will be resecuring the chips that are on the board...
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Hi, Stephen-
I am sorry to hear that you're running into problems. The PIC did seem to program correctly (with a Pickit 2; checksum was right and the PIC tested OK in one of my LEs). If it turns out that the PIC needs to be reprogrammed, just let me know and I'll send you a spare one of mine so the postage is on me. Regarding the pictures, the folks here are great for trouble shooting, so I am sure you'll get it working. You might try double checking to make sure that the PIC is firmly seated in the socket. It looks like it may be in at an angle. hope that helps. Best,
tlh/Terry
Sent from my iPhone using Tapatalk
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Pic not program is just a guess I have nothing to go on. It is lifted in the socket so remove the pic and reinsert it carfully to check. Also tyr pushing the other buttons as if the buttons are in backwards they work backwards and holding them down will make the board work. We have had that before.
RJ
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ok, the only button that is doing something is the select button. When I press the select button down the channel 16 led lights up. The led goes off when the button is released.
One of the parts i did not order from mouser, it is the ST485BN but all the numbers on the part look the same.
And finally I had a lot of trouble getting the led display driver to align properly but I have reseated the chip.
Thanks for all the help guys, I'm confident we'll get this worked out soon.
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Ok that is normal. Can you get an meter and check that you have voltage to the pic chip "24FJ16GA002" It is on the two right top pins on the ship looking at the board normal. Where the test is correct. So the top pin should have +3.3 volts and the second pin directly below it is the grd so put your meter carefully across this and make sure you have the voltage.
the offical pin numbers are #28 and #27 of the chip.
RJ
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Sorry it took me so long, I've been really busy recently.
I hooked up a voltmeter to the pic (I can confirm the serial number is correct as well) and did receive 3.3 volts of DC on the top two pins on the right hand side.
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We found the Data sheet from mouser for the led displays and by using the volt meter to test we concluded that they are not receiving power.
We are getting about 9 volts across the the two leads on the far right side of the display driver.
I don't know if any of this is helpful, but I figured the more info I could send your way the better...
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We found the Data sheet from mouser for the led displays and by using the volt meter to test we concluded that they are not receiving power.
We are getting about 9 volts across the the two leads on the far right side of the display driver.
I don't know if any of this is helpful, but I figured the more info I could send your way the better...
Can you explain where you are reading 9 volts. There should be no 9 volts anywhere but on the raw output of the rectifer in the power supply.
RJ
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I'm sorry I was reading it wrong that should be 5 not 9. And it is the display driver chip SAA1064...
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Sounds like the pic chip is not returning from reset. Try reading the voltage on pin 1. This should read 3.3V to ground pin 27. Also take a look at pin 20, This is the core voltage, This should be 2.5V to ground. Hope you figure it out soon.
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Sounds like the pic chip is not returning from reset. Try reading the voltage on pin 1. This should read 3.3V to ground pin 27. Also take a look at pin 20, This is the core voltage, This should be 2.5V to ground. Hope you figure it out soon.
Yes, that is exactly what I got, 3.3V between 1 and 27 and 2.5V between 1 and 20. What sort of voltage should be coming in and out of the display driver. I think the issue might be with that chip (I had a lot of trouble getting it in place), but in all honestly I know almost nothing about electronics... :-\
Also I'm going to be building another one of these that way if I can get one working I can interchange chips to see what is working and what is not...
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After more testing the top right pin and the bottom left pin of the middle led is getting voltage. The corresponding pins of the other two led's are not getting voltage.
The one is receiving about 2V maybe a little more...
Hope this helps.
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I think your pic may need to be reflashed. The voltage one and not the other display is ok as they are multiplexed so at any time one is powered and the the other two are powered when they are initilized. If the pic is not programmed then this would be normal.
Can't be positive but pretty sure at this point.
RJ
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ok I will send my pic back to be reprogrammed, and we will go from there...
Thanks a lot. <res. <res. <res.
~Stephen G.
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Ok, I sent my Pic to be reprogrammed, It was re-flashed and then testing both in test mode and connected to Xlights. The pic was then shipped back to me and it is not working on my Express. :-\
I'm hoping we can figure out this issue...
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Check the simplest things first:
- Bad solder joints
- Bent pins on IC's
- Bent Pins on LED decimals
- bad 2700pf cap
If all those check out ok then take some real good close up pictures of the front and back of your express and post them and we can go from there.
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ok, i will upload some close pictures a little later tonight...
Until then, I have checked the pins and the cap, also I don't see any bad solders...
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Actually here they are. XD
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A picture or two of the back of the board would be helpful as well.
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hello do you have 3v on both pins 6 and 7 of the Pic to ground?
also I'm I seeing right in one of your pictures every even channel is on?
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OK 2 questions, haven't seen them asked.
1 when you turn on the express, do the 16 channel leds do their cycle test?
2 have you hooked this express up to dmx and tried controlling channels 1-16?
The express may be OK just not showing a readout. Bad display chip?
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He has swapped the chip so that is out. The issue is likely a soldering issue if you moved the board and it changed how it acts. Turn you iron up 15 deg more and clean the board with regular household alcohol and a brush to get the flux off of it. then touch up the all the joints by reflowing them. I bet this will fix it.
RJ
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CombustionMark:
1. no, when I turn the express on the leds do not do a cycle test,
2. No I haven't but at this point I'm pretty confident it's some form of soldering problem.
Also I have tested 2 different display drivers so I don't think that's the problem.
RJ, my soldering iron does not have an adjustable temp, but I will whip it down with alcohol and see what happens.
Also is there any particular place that I should start to touch up the joints or do I just need to go in and resolder everything?
Thanks
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He doesn't mean when you power it up. He is saying that but it does not self test unless you tell it to. Can you get it to self test by booting it up then after you wait 45 seconds push the mode button twice and then the select button.
RJ
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I just finished touching up some solders and cleaning the boas with some alcohol an it seems to e working. :D :D : D I'm going to run it through a test next to be sure.
Thanks everyone I'd be lost without such great help.
~Stephen G.
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You know it has a test function built in, right? Just press mode twice until the display says tst and then press select and it will cycle through the channels and they will all blink simultaneously.
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Glad you got it working!
tlh/Terry
Sent from my iPhone using Tapatalk
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I'm glad you got it working.
Looking at the picture, I would recommend that you invest in a bigger soldering iron.
The solder should wick through the via and solder the component on the front side of the board while you are soldering the back. Most of the components that I can see have very little if any solder on the front (top) of the board. This is typical if the iron is not getting the junction hot enough to heat the via and component lead all the way through the board. It could also be caused by using too little solder or not enough flux. Using rosin core solder, the flux is not normally a problem...
RM
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Congratulations! you now get to look foreward to many more. They should a lot easier now that you have your first one down.
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I just finished touching up some solders and cleaning the boas with some alcohol an it seems to e working. :D :D : D I'm going to run it through a test next to be sure.
Thanks everyone I'd be lost without such great help.
~Stephen G.
You are not that far from me. I live in Cleveland Tennessee.
If you want to have a Mini sometime and go over anything, let me know. Also have a Pickit 2 for programming.
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I am about another hour away in Vonore TN.
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Hmmm thanks for the info RM397, in an attempt to save money I'm using solder leftover solder that my grandfather had. I have no idea how old the solder is but it seemed to work fine so I wasn't concerned (at the time).
My soldering gun isn't too fancy either, I might upgrade before I build any more of these...