Finished soldering, lcd has black row of squares...


 
R

RWilloughby

TVWBB Member
Hello all. I need some advice for troubleshooting. Its my first time with a project like this! I finally finished all the soldering for now (Need to get case to finish installing leds). I wrote to my SD card and inserted it as instructed here. Its being powered via the Raspberry Pi B. The LCD never lights up or shows '-No Pit Probe-'. I've verified that the SD card has files on it, i've reseated the card. I've also removed and reseated the ATMega chip. For my pit probe connectors I see some joined, but it looks similiar to others. The closest connector I found is on the left row of the ATMega across from the letter 'e' in HeaterMeter but blowing up the pic it shows a very thin seperation. The LCD screen was put on backwards so that fun flipping.

Here are some pics of the board, as well as a closer look at part of it.

IMG_20150131_144734_zpscf339912.jpg


IMG_20150202_094702_zps0880e491.jpg


Here is one without the pi connected:

IMG_20150131_144615_zps52f1b58e.jpg


Thanks for any help/ suggestions!
 
Boot the raspberry pi on its own with a monitor/tv connected to the HDMI port and see if it's really booting up or not.
 
Did you adjust the blue trimmer resister. You need to do that so the display shows the alpha numeric characters. Try that and see what you see.

Also, welcome to the site!!
 
Steve_M, I just booted up the raspberry pi to the tv and all looks good, I saw no errors. When I connect it back to the heatermeter, the display then starts producing errors:

IMG_20150202_130440_zpsac35293b.jpg


Bob, it wasn't until I adjusted the blue dial that I saw the black squares.
 
Those last fews lines on the screen about EXT4-fs errors aren't good.

You need to re-flash the SD card or try a different card.
 
Something def happened to that SD card. I've replaced and flashed it. I don't see any errors on the screen this time, but LCD still shows black squares. I feel that we are making some progress.

IMG_20150202_135228_zps9347b638.jpg
 
When you fixed the display orientation, it's possible that you may have damaged some pads.

The ones on the right side look to be in worse shape than the ones on the left.

Check these for continuity.

 
You also may want to try pressing enter at that console and typing `avrupdate` to make sure the ATmega is up and running. It shouldn't say "Fuses ERROR".

EDIT: I just noticed the first post. Are you powering up your device with it sitting on Aluminum foil? That's a really bad idea because aluminum is conductive and there are plenty of exposed pads and pins on the bottom of a Pi.
 
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Starting from the left, straight lines 2 & 4 made my analog multimeter twitch only a bit. The rest of them were no problem.
 
Bryan Mayland said:
EDIT: I just noticed the first post. Are you powering up your device with it sitting on Aluminum foil? That's a really bad idea because aluminum is conductive and there are plenty of exposed pads and pins on the bottom of a Pi.
Click to expand...

It more looks like an anti-static bag than aluminum foil, but nevertheless those anti-static bags are also conductive on the outside, and likewise the heatermeter should not rest on it when applying power.
 
Bryan, rookie mistake, yes that is a anti-static bag the pics were taken on.

I was able to run 'avrupdate' successfully. At least I don't see a 'fuse error'.

IMG_20150202_173119_zpsf11d7fc3.jpg


Steve_M, looks like i'll have to look into adding a jumper wire.
 
Well that is excellent news, it means the AVR should be working properly. Sounds like you just need some jumper wires and and you should be in business to the LCD data lines. You may need to do the R/S and E lines as well to the left, which are also connected to that shift register.
 
Gentlemen, thanks! Steve_M, thanks for the suggestion of jumping the two bad leads - that fixed it! Bryan, thanks for the work around to test the s/w install. That gave me hope that this project could be rescued!

I'm happy to report I'm getting the LCD to show '-No Pit Probe-'. Now to start working on getting a case, and investigating fan options!
 
Well, need to bring this thread back unfortunately. All is functional, but the display. I must have tweaked something when I put it in the case as its back to black squares. I checked the continuity on the ones were I had to add jumpers and all is good there. Before it went to the black squares, it would occasionally have garbled text. I would reboot it and it would be ok. However, thats not the case anymore. Any help troubleshooting would be appreciated!
 
You could try reflowing the solder on the shift register IC, the LCD data passes through it on the way to the display...

Here is a diagram showing where the LDC wires connect that I made to help someone else troubleshoot their LCD issues, perhaps it will be helpful to you.

LCD.jpg
 
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Thanks for the diagram. I went though and checked all the continuity between the green lines and they checked out fine. Do you still recommend reflowing?
 
Since those are all direct traces (with no components in between) I would say testing for continuity would be good enough, it either has it or it dont. (If there were other components connected to a trace there would be the possibility of a branch running on the other side of the board, in which case it would be possible to have continuity on the bottom but not the top of the board. In this case that shouldn't be an issue).
Did you test continuity to the solder joints on the HM board or the LCD board itself? If you tested the HM side you should go back and test from the LCD side to make sure it is good there. If that's all good the next thing I would suspect is a bad trace on the LCD board itself, they tend to be kinda small and fragile. The LCD should have a header on both sides of the board, test continuity from header to header on the LCD, that might help you find which is the problem trace.
 
RalphTrimble - thanks for the suggestion on testing the LCD Board. I did that and found no continutity on the 15 pin.

20160928_123701_zpsc485thek.jpg


Anyway to do a jumper on that?
 
Yah, jumper just like in the image you posted and hope the trace runs from the empty hole to where it needs to go and not through the broken part somehow. Most likely it will, but if not you will have to get a close look at where the broken trace goes and add a jumper to there instead.
Although I think pins 15/16 are for the backlight so that might not be the problem if you are experiencing an issue other than no backlight....
 
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