New build - LCD question


 
You know, I've got a Fluke76 True RMS meter and when I throw it on that pin measuring DC voltage I see a tiny flicker.... So don't get hung up on that "bouncing voltage" thing, perhaps you can't see it with your meter.... My display is working, this is/was a $200 meter, I don't see bouncing either...
 
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Sadly, I lost my True RMS meter somewhere in a move. I have a little Greenlee that gets me through most everything I need.
 
I am looking at your picture showing all boxes on the LCD and it sure does look like the BLUE CONTRAST POT is in the zero (fully counter clockwise) position??? I know I have mentioned this time and again, but have you adjusted the CONTRAST POT? When my LCD is readable the pot looks like a "T" yours looks like an "X".... When my contrast pot is tuned to look like an X I see the same boxes on my display too....
 
Oh yes. I turn that thing just about every time I plug it in. The whole way to the left, I get both lines of boxes. About 1/8th turn to the right and the bottom line disappears.

Another 8th turn and the top disappears. The screen remains blank through the rest of the turn to the right.

Do you think my power supply might be an issue? Aside from the rPi, that's been the only constant between the two builds.

It's from a Netgear router and is 12V 2.5A
 
if you UNPLUG the 12V power supply you can plug the rPi into a USB port to power it and the HM. The blower will not function but the rest of the HM should.
 
post a pic showing all the pins of your LCD , particularly the ones that line up next to the shift register (the 6 pins you didnt post a pic of)

For the life of me I can't figure out what is going wrong here, even more puzzling is to have it happen twice in a row the exact same way? What are the odds?
 
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Can you switch the green and yellow LEDs on and off, using the the webinterface?

If you can then the shift register is working, if not then the there is something wrong with the shift register or with the connection between the atmel and the shift register.
 
That's a good suggestion Peter, though he is kinda behind the curve on HM operation in general having not had a fully working HM in his hands as of yet.

The web interface seems to be working, the probe config seems to be saving and probe settings and are registering temps, so we're CLOSE!

On the config page check the LCD/LED config, set an LED to "Output > 0%" and enter a setpoint higher than room temp (higher than the PIT PROBE is registering) and the LED should come on. Toggle lid mode by hitting the HM button to the left and the LED should go off...
 
Again, I have a Yes and No answer.

I set the Red LED to "Output > 0%" and the Pit Target Temp to 225 and Saved the config.

When I push the stick to the left, the web interface shows me Lid Open and the Yellow light comes on (the Yellow is set for Pit Open). I can only get the lights to turn on if they are set for Pit Open.

I think I am done with these things. I'm ready to drop back and punt.

Ralph, if your offer is still valid, I'd like to send you what I have and see if you can make heads or tails of these things. I will pay you for any parts and your time.

Thanks!
 
Your HM boards were delivered today. I didn't have to read your notes to know which was which.... LOL

I powered your first build, which looked to be in rough shape. AFU, moved on...

Your second build looks pretty clean, looking at it I would think it should work. Powered it up, LCD still DOA, LED's seem to do what I tell them to do... HM seems to be working other than LCD. So I powered down and did continuity test from each LCD pin to the nearest via or solder joint on the LCD board. All good up to Pin 6, no continuity to the nearest via... There is a tiny break in the trace where it leaves the solder pad the pin goes through on the LCD board. I scraped away some of the (green) resist and soldered a small piece of jumper wire there to complete the circuit. BINGO!
FIXED1.jpg


So nice to see "NO PIT PROBE" in a situation like this! I haven't powered with the rPi or fully tested the board, but it looks clean so I think we've got one working board at this point.

On the second board I've tested all the traces on the LCD, all good, and from the shift register to the LCD header, all good. I tested your power supply, 12V good, 5V good, 3.3v good. This board appears NOT to be functioning, though I have swapped your ATMega's and they both are programmed and working in board #2. Looks like it might be an issue with connections on the ATMega or something odd that blew when you shorted things out, or a part out of place. Gonna take a bit more digging on this one....
 
Update: Did some touch-up soldering on the second board, seems to be functioning now because red and green LED come on and go off with Lid Mode.

The LCD is sill AFU. Debating on the next move, the shift register looks like its been pretty hot, and the cap on the end was kinda roasted on top. I swapped the cap because that is easy, no joy... I am debating at this point whether to swap the shift register or LCD... Both tough jobs, and I can't think of a way to tell for sure which item is bad... The shift register seems to be working, at least the section that controls the LEDS, but you did short something out so who knows... Do you remember exactly what pins you touched when you shorted it out? That info might help my decision...
 
Update: I decided to go with the LCD since the shift register was working for the LED's, it was a good decision because I've got the second board working now! I guess the LCD got fried somehow in the chaos of your first build.

So far so good, I am crossing my fingers for your rPi right now, gonna plug that in next...
 
Nice! Thank you!

It had to be a workmanship error, I just couldn't find it.

Everything seems to be breaking on me lately. Airbag light in my car came on, throttle wire snaps on my lawnmower, get the airbag fixed, the radio dies in my car, work phone crashes, 3 days later my work laptop crashes... I'm afraid to touch anything!

Thanks for all the help, I really appreciate it!
 
Nice work! If you do a lot of soldering, you should invest in a hot air rework station (it's like a precision heat gun). It makes pulling apart pieces with multiple solder points a breeze
 
I've done a lot of soldering in my life but try to do as little as possible these days, so I can't see me investing in a hot air rework station, though I have thought about it a few times. I actually got the LCD off the board and new one on pretty quick and it worked right off the bat, so I can't complain, still have mad solder skills I guess...
 
CSchaaf said:
Nice! Thank you!

It had to be a workmanship error, I just couldn't find it.

Everything seems to be breaking on me lately. Airbag light in my car came on, throttle wire snaps on my lawnmower, get the airbag fixed, the radio dies in my car, work phone crashes, 3 days later my work laptop crashes... I'm afraid to touch anything!

Thanks for all the help, I really appreciate it!
Click to expand...

Damn, that's a streak of bad luck there.... Gonna have to pass on helping you fix that pile of crashed electronics... lol
 
Update on progress:

I got the second build 100% now, it did have some additional problems. The probes were not registering properly, some would randomly start registering temps without a probe being plugged in, and would register temps falsly high when you did plug a probe in. The noise icons were also constantly on screen for every probe.

I found some of the legs on the filter capacitors were cut too short and not protruding out of the solder side of the board much if at all. I did a solder reflow on the first probe making sure to get solder to flow to the component side of the board and it fixed the problem, so I decided to just reflow the entire board....

I left that board powered all night with the rPi and a RD3 connected, it's still working perfectly, temps are rock solid, TC matches TW probes, no noise icons, rPi/web interface still responding after 12 hours.... I call this one done....

The second board is working but it has the same exact problem with the probes as above. I am gonna do the solder reflow now and hope it does the trick a second time.

The lesson here is don't trim the legs on your components before you solder them to the board, if you do make sure you leave enough leg to touch your soldering iron to and make the solder flow to connect everything.
 
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