New Build - need help


 
M

Mike Atlanta

New member
High everyone,
I just finished my building my first HM (version 4.2.4) and powered it up but nothing happened. I've tried powering it with both the pi's usb and the 12v DC on the HM but still nothing happens. I can see 12V on the board, but not 5. I suspected I had a problem with the 5 Volt regulator, IC1, because I had 12 V on the input but only about .5 on the output. so I removed it and tested it by itself on a breadboard and it worked fine - 12 v in and 5 out. Any ideas? I suspect I have a short somewhere or a solder bridge, but I cannot find it anywhere. I did have a solder bridge on the mosfet, but corrected it and still no luck - could something have gotten damaged? Any help or suggestions on where to look would be appreciated. Also, I forgot to mention that the pi works fine on it's own.

Thanks,
Mike
 
supply pictures of your soldering (both sides of board). Have you tried turning the potentiometer to see if the LCD lights up? Are you powering via USB or power supply?
 
Hey Tony - thanks for the quick response. I'll send some attach some pictures when I get back to my lab. I have played with the POT and have tried both USB and the 12V power supply on the HM board.
 
Where's your ATmega328P chip? The soldering looks reasonable but it's hard to see in those photos/lighting.
 
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I had taken it out before taking the pictures because I was cleaning up a few solder points. The chip was installed in all my testing.
 
Don't take this the wrong way but was the chip installed facing the right direction. I deal with Eproms everyday and sometimes if I am in a rush I will still put them in backwards.
 
Ok, I found the problem. I discovered that I had a short between +5 and GND - the problem was finding out where. After looking at the board with a magnifying glass and at the zoomed in digital images with no luck, this morning I noticed a piece of solder protruding out from between the LCD and the HM board. I wasn't sure that this was the problem, but with nowhere else to look I decided to try and separate the two boards. I didn't get the LCD fully removed, but I removed some solder on the first six pins and separated the boards enough to break the short. I booted it up with the pi and saw it come to life. Now I have to figure out why it didn't say - no probe (none were connected) but instead said probe 2 at 400 (can't remember the exact number) degrees. Also, when I went to the devices url (http://heatermeter.com/devices/) it said timeout for 192.168.200.1 and error for 192.168.1.66. Note that I'm hard-wired connected right now to the network.

At least I'm making some progress, hopefully nothing was damaged with the short. I'll tinker some more with it tonight when I get back home.

Thank you Chris and Tony for your help.
 
Mike,

The No Probe issue should sort itself out once you switch Probe 0 to Thermocouple in the web GUI.
 
Ok, I have most of it sorted out, but for some reason probe 2 is still showing what seems to be a temperature countdown (no probe connected). It starts out somewhere between 300 and 500 and then slowly drops and later rises back. Is this another short? The other probe ports seem to work ok, including the thermocouple, but for some reason probe 2 is behaving very strangely (configuration for it is same as probe 1 and 3).
 
Definitely check the soldering for probe 2. It soulds like the connection to the atmega is floating, meaning its not connected to anything at all.
 
Hey John - thanks, you got me on the right track. My probe was soldered to the board, but I wasn't getting any continuity from the back pin of probe 2 to the 10k and 100k resisters behind it. I must have damaged the board and broke that connection at some point in my build so I just added more solder to bridge the probe to the 100k resister. It looks ugly, but everything seems to be working now. I can't wait to try the whole system out. Thank you all for your help.
 
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I get that when I forget to solder a 100K resister to the thermocouple and it takes me a hour to figure out, lol that I missed soldering in the 100k resister.

Glad its working, if want you could add a small wire to bridge the gap by soldering one end to the Atmega and the other to the 100K resister.
 
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