heatermeter suddenly died?


 

Fred van Zoggel

New member
Hi,

My HM suddenly stopped working today. I had it assembled by a friend a few weeks ago and last week i had let it do it's thing for pulled pork : worked great!
I ordered a thermocouple from Auberins which arrived this week (the one i have now was not easy to attach to my bbq, but worked).
Today i wanted to try this new TC for measuring my fridge temp (soon to be dry aging fridge). After a few changes in the HM- web page, it suddenly stopped working.
Right now all 3 led's are on and it says no pit probe without illuminating the screen. After a few seconds the message goes away and the screen lights up. Still with all the led's on.
I have no idea what has happened.

I took the Rpi-3 off and re-installed the image : didn't work.
I took the Rpi-3 of my neighbour : didn't work.

Does anybody know what to do, before i have to by me a new HM? I can measure things, just don't know where to start or what to measure.
All help would be very appriciated!

Here is an image of what it looks like
20170211_1629371.jpg
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Here what the web page says
 
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That graph looks like the HM is not communicating with the rPi. I would examine/reflow the solder on the rPi socket on the HM board and maybe the ATMega too (remove the chip before you solder the socket)... and get a case for your HM, having the boards loose like that allows things to flex around or easily short something out with a probe braid or whatever, you're just asking for trouble with loose boards like that.
 
Thanks for the reply, just to make clear:
I do have a case. I just got it out to look for bad soldering points. It's on the floor because that's where my router-cable is (installed the image again). The moment it suddenly crashed was when it was still in the casing. Will first try to check the solder points like you said. It will take a little while (just don't have the experience yet...)
 
The cat5 cable is not plugged into the correct rj45 if it's for the blower. And you are trying to power the heatermeter with the wrong power cord. You need to use the 12v adapter don't plug anything into the Rpi
 
Just to clarify without wanting to be rude :
The cat5 cable comes from the router and is plugged into the Rpi because i wanted to reinstall the software and started from scratch. As for the power : github says to power up the HM for the first time with the Rpi cable, so i did just that. I do have a suitable 12v adapter, which worked previously, but like i sayd, it suddenly crashed. The Rpi is still good, tested it with another image (retropie).
If i was only a little better in soldering......
 
I'm pretty sure I've made both mistakes and not fried the rPi or HM (plugging my LAN cable into the HM Cat5 jack and the blower into the rPi lan port) Though I haven't powered from the HM 12v and the rPi at the same time, so not sure if that will fry things. Since you have swapped rPi with a known good rPi (if I read that right) and it still doesn't work most likely your rPi isn't fried.
At any rate, it seems the HM is not communicating with the rPi so you can check the schematic and find the traces that connect the ATMega to the rPi and check them, or do like I suggested and reflow solder on both sockets and hope that clears up the communication loss. Since it just failed at random while in a case most likely nothing is fried, there is probably a bad solder joint that oxidized over time and is now failed. That would be my guess, though I may be missing pieces of the puzzle.
 
All help is appreciated John!
I think like you said Ralph,it has something to do with the soldering.
I unplugged the Rpi, now the HM still says "no pit probe" with the lcd unlit. When the Rpi is attached, the HM says the same, but after about 30 seconds, the lcd lights, only no text. I did check the soldering parts, but like i said, i'm not the professional in this. I think it will be best to let the guy look at it who assembled it for me, before i manage to get it damaged even more... Still it keeps making me wonder why it suddenly stopped after a good run of 23 hours.
 
Post a closeup picture of the board and maybe someone with a better eye for soldering can see where there may be a problem. There's probably a solder joint that only makes connection if there is pressure on it one way or another and that's why it worked a while then failed.
 
Here are some pictures. If not sharp enough, i will try again tomorrow at daylight. the interior doesn't help at this time (11:30pm).



 
Yah, the pics are dark and get blurry when I zoom.

I looked at the schematic, the pins you need to look at on the ATMega are 1,2,3,17,18,19, those all go to the rPi socket.

On the rPi socket:
pins 3,5,6,7,18,20 are the ones where the data comes from the Atmega
pins 1,8,14,15,17,22 are gnd
pins 24,26 are +5VDC

...but like I said, easiest just to reflow the solder on all the pins on both sockets while you have the iron hot.
 
Yeah, Ralph is correct, you need to reflow the connections.

It sounds like you have a solder joint that when it starts to get warm it makes connection with the ground plane and shorts out
 
I tried the soldering of the connections, but it was very very clear to me that it's not 1 of the things somebody should ask me to do........at least not this kind of miniature stuff!
I am not yet ready to give up, because i allso think it is repairable. I sent a pm to one of the members here who lives in the Netherlands. Hopefully he is willing to give me a soldering hand.
I'm just too afraid to make more damage to it rather then to make improvements...
 
I guess everyone knows their limits...
For the record, the only thing that is "miniature" on the HM are the SMD parts on the thermocouple amp, you wouldn't need to touch that stuff. The IC and rPi sockets are fairly standard size as electronics go. Doing solder reflow is a bit easier than doing the initial soldering, good eyesight is most important here franky, or use lots of light and magnification to see clearly how the solder joints look.
Tin the soldering iron tip and touch each solder joint briefly (make sure you touch only one at a time), solder should melt and flow around the leg nicely. It's pretty easy... it seems you are resolved to the idea that you are not up to the task, if you can manage to get some local help that's great, otherwise come back for pointers if you decide to take it on.
 
Sounds easy the way you say it. Too bad the midwest isn't near Belgium.....I did more soldering in the past, but that was mostly connecting cables, pretty easy. I think my iron is too big for this kind of work (and the lack of skill). Like i said, i hope mr. Peter F will be able to help me. The plan in the future is to make another one for my other bbq, so i have a little time to learn the skills..... Right now i will get busy with my drying fridge, so it's not that i have nothing to do...
As soon as i have made progress with the HM, i will post what was the problem.
 
The person you contacted, I believe I know whom you contacted should help ya.

It's really not that hard to do all thats needed is an soldering iron and heat, you may need to add some solder, but I bet you won't need it.

After the iron is hot, just touch each solder joint for one second, and that should do it. If you see any copper showing, then you can add a touch of solder.
 
I don't know if this will help you or not, but my HM was acting wonky the other day, with similar issues to yours. I just needed to pop out the SD card and re-install it firmly.
 

 

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