Re: Lynx Manual question #2

[sirwesley]

I just completed the V2 board of EXPRESS, and it states that an LED should light up when I plug it in.  However, I get nothing.  Which LED should light up or should they all light up?  Should I see anything on the LED Digits?  Is there any good way to see if everything is running correctly?  I will start going back through all my solder joints in the mean time. 

[memphislights]

The V2 boards do not have the 5V and 3.3V indicator leds.
The V3+ boards do.

[sirwesley]

And now...I've released the magic smoke monster.  Started probing around with the volt meter and pooof!  Now what?  My Pic24 still is good, but the two big resistors @ AC in are fried.  Any suggestions?  Do I need to start over?  What can be salvaged if anything? Is there any good place to read some voltage from the board?

Do both AC in need to be plugged in?  I did find that I was missing a 180Ohm resister at the end of the 16 LEDs.  Would that have caused a problem?

I will try just replacing the 2 15k resistors and add in that missing 180 resistor and try again, unless someone has a better idea.

[RJ]

Would help of you can post some good pictures I could maybe tell more about what damage was done

RJ.

[sirwesley]

I will take some pictures of the board and post them later on this evening EST.  I went ahead and De-soldered the two "Deep Fried" 15K resistors, so those will be missing.

And can anyone answer the following: Do both "AC in's" need to be plugged in?  I did find that I was missing a 180Ohm resistor at the end of the 16 LEDs.  Would that have caused a problem?

Thanks so much for everyone's help.

[rrowan]

I will take some pictures of the board and post them later on this evening EST.  I went ahead and De-soldered the two "Deep Fried" 15K resistors, so those will be missing.

And can anyone answer the following: Do both "AC in's" need to be plugged in?  I did find that I was missing a 180Ohm resistor at the end of the 16 LEDs.  Would that have caused a problem?

Thanks so much for everyone's help.

You only need the left AC in to power up the board (pic, 7-segment LEDS, etc) and the first 8 (108)channels. The right AC in power up the remaining channels (9-16)

Missing 180 ohm resistor would not cause the magic smoke, most likely a solder bridge. You didn't do the power mod and plug in both AC ins did you?

Rick R.

[sirwesley]

@rrowan:  I just used the left AC and I have not done the bridge/power mod.  My question is, should I see any indication of a working board when I plugged it in? I mean, was my board working, and I fried it by probing with the voltmeter?

Here are some pictures of my sad sad board.

[rrowan]

@rrowan:  I just used the left AC and I have not done the bridge/power mod.  My question is, should I see any indication of a working board when I plugged it in? I mean, was my board working, and I fried it by probing with the voltmeter?

You only need the left AC in to power up the board (pic, 7-segment LEDS, etc) and the first 8 (1 - 8)channels.

Yes the board was power up with only the left AC in. If the 7-segments display didn't turn on. The normal problem is the pic or programming of the pic. With ver 2 board you really need the display working, later boards have the 3.3 and 5 volt power led indicators on them.

Replace the burnt out resistors and see if it will work.

Rick R.

[vairmoose]

My eyes may be deceiving me, but there appears to be a dark shadow on the back of the board between two pins of the PIC (I think pins 18 and 19).  Also there is a lot of flux residue on the output connectors on channels 1 through 8.   That residue could be hiding  a solder bridge.   

Just my 2 micro-cents worth.

Larry

[sirwesley]

But my indication that the board is working should be something lit up on the LED Digits display...is that correct?  Is there a good place to probe for voltages?  I saw on another thread, that there might be a component from Mouser that could be in question. 

[sirwesley]

I think I'm just going to count my losses and start over, I just discovered where I pulled up a pad when I de-soldered. 

RJ, do you have any more Express boards on hand??

[PJNMCT]

I think I'm just going to count my losses and start over, I just discovered where I pulled up a pad when I de-soldered. 

RJ, do you have any more Express boards on hand??

You still may be able to save it...go upstream of the bad pad and solder a wire in parallel with the trace, then solder the other end to your component.

-Paul

[sirwesley]

I know everyone is working hard to get all their Christmas stuff together, but does anyone have the time to take a look at my board.  I can mail it to you and pay you whatever you think is reasonable to fix it and pay shipping both ways, I just don't know where to go from here and I hate to just trash it. 

If you can't get to it til after the season is over I understand, but maybe I can salvage it for next year with your help.  Thanks.

[memphislights]

I have time at night to troubleshoot it if you can get it to me.  No cost, just the shipping back and forth.