DiyLightAnimation
Hardware => Lynx EtherDongle => Topic started by: Steve Gase on March 26, 2012,
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I have 2 EtDs that were built by someone else but not working. I have 2 more EtDs that I just built.
After loading pixelnet firmware into all four I started with my first test... connecting power, then ethernet.
3 of the 4 units are fine so far... i'm stopping for the night.
the 3 have a green led on the board, and when connected to my ethernet swith I get ethernet activities lights -- solid green and flashing yellow.
the 4th unit looks broken. with power I get the green led on fine. BUT the is no activity on the ethernet connector.
solder points look good to me. chips appear to be oriented correctly. i don't see any bridging -- even on the surface mount chips. when i burned the firmware i also did a verifiy (as always) and it had no problems.
Any idea on what next to try? (i'm thinking of swapping swapping socketed chips with a working unit next.)
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Now you have been here long enough to know that good closup pictures are required to assist in diagnosis and to help rule out the simple things.
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According to RJ "It is not a power indicator. It is connected to the ethernet phy chip. It is an indicator for it." I had a hard time getting my ED to work check out this post for some things to try: http://diylightanimation.com/index.php?topic=7735.0 Common problems, bad Xtal's (post has procedure for checking), solder bridge on ethernet chip (I looked five or six times and did not see one but when I went around the chip with flux and desolder braid it fixed the problem).
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It was late at night, so I thought I'd post the question before the pics. :)
I swapped out socketed chips and the questionable chips worked in another board, and good chips did not work in the questionable board.
I checked all of the soldering and could not find anything -- touchups did not work.
I finally used a magnifying glass and found what I think to be the problem... a missed leg on the small surface mount chip -- pin #1 and I can't read any descriptive text on the chip. ???
can someone confirm that this particular problem would cause the described behavior?
next... what do people do when we get a bad surface mount? is this problem even repairable? do I buy a new kit? do coop managers plan for failures and have a few replacements in reserve?
thanks.
(http://img443.imageshack.us/img443/1584/imag0789m.jpg)
http://img443.imageshack.us/img443/1584/imag0789m.jpg (http://img443.imageshack.us/img443/1584/imag0789m.jpg)
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Unless I am nuts that is not a broke leg you have all 12 on that side it is a rouge piece of material that should not be there.
There is 12 legs on each side of that chip.
Am I correct?
RJ
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<fp.
it looked so realistic! i used tweezers and it came out and blew away. ::)
so... back to an unexplained issue.
here is the front and back-sides of the board.
Front: http://img192.imageshack.us/img192/6818/img0406vn.jpg (http://img192.imageshack.us/img192/6818/img0406vn.jpg)
Back: http://img99.imageshack.us/img99/9094/img0408r.jpg (http://img99.imageshack.us/img99/9094/img0408r.jpg)
I didn't solder this one, and I've wondered of the tinge of black -- is it from an iron that is too hot? or a different kind of solder?
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is there a solder bridge on the long dual row of pins?
about 8 or 9 pins down on the outside?
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On the back side, near the magjack, there are a number of solder joints that don't look like they have flowed correctly; I still see the gold plating on the pads. Try reflowing them and see if it helps.
/mike
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is there a solder bridge on the long dual row of pins?
about 8 or 9 pins down on the outside?
no bridges. but there was some of that blackened residue. it cleaned it up and also did the same for each of the other tight spots.
still broken.
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I hope the black is not from someone using plumbers solder. I had a dongle sent to me like that once years ago and I had to remove all solder clean and resolder the board to get it working. It had black goo of a flux not like normal rosin. I do not know that was what is was but they jonits also were grainy. Almost lilke no lead solder but with black goo on it.
RJ
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I'm thinking that your iron is not hot enough. Many of your solder joints have not flowed through the board. I usually use too much solder which makes little balls on the other side of the board, but I know I've got a good connection when both sides of the board look like they've be soldered.
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I hope the black is not from someone using plumbers solder. I had a dongle sent to me like that once years ago and I had to remove all solder clean and resolder the board to get it working. It had black goo of a flux not like normal rosin. I do not know that was what is was but they jonits also were grainy. Almost lilke no lead solder but with black goo on it.
RJ
My helper used good solder.
I got the solder at Altex.
It say's Core Solder.
Sn60Pb40
RA300
3.3%fux
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I'm going to do the following tonight:
- get better light and magnifying glass
- use flux and braid to do thorough check around the SMT chips
- reflow all of the connections -- add more solder with sufficient heat to get it to come through to the other side of the board
- clean up solder spatter
- check voltages:
- crystal voltages (Xtal should read 3.3 volts between pins 4 and 8 and 1.6 volts (approx) between pins 4 and 5 )
- 5V regulator (7805): 7.98V on pin 1, 0V on pin 2 and 5.00V on pin 3
- 3.3V regulator (117v33): 0V on pin 1, 3.29V on pin 2 and 5.00V on pin 3
If I'm not successful, then I'd next like to have some info on other meter readings -- which specific locations to test, and what readings to expect. Hopefully someone can share the technical details.
These threads have been excellent for information... can links to each be added to the wiki us "Troubleshooting Discussions"?
http://diylightanimation.com/index.php?topic=7371.15
http://diylightanimation.com/index.php?topic=7735.0
Thanks!
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I'm going to do the following tonight:
- get better light and magnifying glass
- use flux and braid to do thorough check around the SMT chips
- reflow all of the connections -- add more solder with sufficient heat to get it to come through to the other side of the board
- clean up solder spatter
- check voltages:
- crystal voltages (Xtal should read 3.3 volts between pins 4 and 8 and 1.6 volts (approx) between pins 4 and 5 )
- 5V regulator (7805): 7.98V on pin 1, 0V on pin 2 and 5.00V on pin 3
- 3.3V regulator (117v33): 0V on pin 1, 3.29V on pin 2 and 5.00V on pin 3
If I'm not successful, then I'd next like to have some info on other meter readings -- which specific locations to test, and what readings to expect. Hopefully someone can share the technical details.
These threads have been excellent for information... can links to each be added to the wiki us "Troubleshooting Discussions"?
http://diylightanimation.com/index.php?topic=7371.15
http://diylightanimation.com/index.php?topic=7735.0
Thanks!
Hi Steve,
I hope you find the problem. If not then maybe RJ can give you more info for meter readings.
As far at the Wiki, Sure it can be added but to be honest links back to the forum in the wiki for troubleshooting is not a good option. Putting the text info in the wiki that is in those links work much better.
Rick R.
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- get better light and magnifying glass
- use flux and braid to do thorough check around the SMT chips
- reflow all of the connections -- add more solder with sufficient heat to get it to come through to the other side of the board
- clean up solder spatter
- check voltages:
- crystal voltages (Xtal should read 3.3 volts between pins 4 and 8 and 1.6 volts (approx) between pins 4 and 5 )
- 5V regulator (7805): 7.98V on pin 1, 0V on pin 2 and 5.00V on pin 3
- 3.3V regulator (117v33): 0V on pin 1, 3.29V on pin 2 and 5.00V on pin 3
:-\
There did seem to be some bridging on the PIC. I used flux and then the solder sucker and it now looks good.
I tested the regulator and 50 xtal voltages described above -- and they are good.
So, I've run out of ideas. it still doesn't work.
To summarize -- I have 3 units that show life on the magjack, but unit #4 does not.
I know that the cable is good (because of the success of units 1-3).
The power LED on units 1-4 ALL come on.
voltages on 50 xtal, and each regulator all match the numbers aboe.
Other tests to try out?
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Make sure that when you cleared the bridge that you didn''t completely open the connection as well. A solder sucker can do that pretty easily if all of the contitions are right.
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Yes solder suckers are not a good idea on SMD. Wick is the prefered way since it is hard to pull all of solder out of a joint with it.
Look for any "dry" pads to pin areas now.
RJ
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- get better light and magnifying glass
- use flux and braid to do thorough check around the SMT chips
- reflow all of the connections -- add more solder with sufficient heat to get it to come through to the other side of the board
- clean up solder spatter
- check voltages:
- crystal voltages (Xtal should read 3.3 volts between pins 4 and 8 and 1.6 volts (approx) between pins 4 and 5 )
Did you verify the Pic chip is programmed with the correct code?
- 5V regulator (7805): 7.98V on pin 1, 0V on pin 2 and 5.00V on pin 3
- 3.3V regulator (117v33): 0V on pin 1, 3.29V on pin 2 and 5.00V on pin 3
:-\
There did seem to be some bridging on the PIC. I used flux and then the solder sucker and it now looks good.
I tested the regulator and 50 xtal voltages described above -- and they are good.
So, I've run out of ideas. it still doesn't work.
To summarize -- I have 3 units that show life on the magjack, but unit #4 does not.
I know that the cable is good (because of the success of units 1-3).
The power LED on units 1-4 ALL come on.
voltages on 50 xtal, and each regulator all match the numbers aboe.
Other tests to try out?
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I am in the same boat as Steve, I finished putting together my second ED and after programming the PIC successfully I plugged power into the ED and the green light came on right away which I new was not right. I then tried plugging an ethernet cable into the MAGjack and no lights lit on the MAG jack and there was no connectivity on my switch. I checked the voltage regulators and get 4.99 off the 7805 and 3.35 off the 117v33. The Xtals check out fine at 3.3 on the inputs and 1.67 on pins 4 and 5. I went around the board and retouched everything. I also went around the edge of the Network chip with flux and solder braid and well lests say I won't be doing that again, I did seem to get all the bridges that formed on the one side cleaned up but I am not happy with the results. Needless to say when I plugged the ED back into power I got the same results, Green LED comes on right away and nothing on the MAGjack when plugged into the switch. (Yes the cable and switch are good as my other ED works just fine). Attached are pictures
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If the pic is programmed you should have got the green led. This was not incorrect it sounds like it was fine. This could be a cable issue or something simple like that. But you will have to be careful you have not added a solder issue on the chips now. I see a lot of solder laying around near the smd chips.
Some of the solder joints look a little blob like. And there seems to be a lot of flux all over the pcb bottom.
I would clean the pcb with 91% alcohol (get it at walmart/walgreens, ect) and a brush and then turn you iron up another 10 deg and then use a little tiny bit of flux from a pen on the joint if you have one and then reheat the joint till it flows clean and shiny like mercury(under 3 sconds if all is correct) do not add any more solder there is more than enough there to use. Then move to the next joint and do the same.
For everyone if your pcb came from the scond batch you should have a very good reason before you mess with the solder on the chips. They were check very well and were placed by machine and reflowed in temp controlled oven. There should be little issue with those pcbs. I just dealt with two of these the users believed was the smd and it turned out it was their solder jobs and they both had redone them and were sure the smd was the problem.
There is a better chance if your pcb was in the first batch of a smd issue but should be very little on the second batch.
RJ
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I cleaned the PCB off with Alcohol and noticed then pin 15 is bent into pin 14 on the Network chip, is it supposed to be like that? I will put a fine type in my solder station and try reworking the joints that are blob like and try to clean up the mess I made on the network chip. The cable I used is good because I plug my good etherdongle into it and it worked.
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Yes this can happen pretty easy using solder wick on the small pins. if the wick at the ends away from where you are heating cools too much when you move the wick the pin is stuck to the wick and does that. It is a real delicate trick but can be mastered with patience and steady hands.
RJ
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UPDATE: Straightened the bent pin and retouch all solder joints using a flux pen, also retouched pins on net the one side of network chip where pin was bent and tested without success. So as of this point I am throwing it into the broken box and moving on to other things as I am at the end of my capabilities with this board.