Did I bugger it up?

Managed to get my HM 4.2.4 assembled tonight and can log in. Pit thermocouple and 3 probes reading accurately.

Unfortunately it was not in a case when I decided to hook the fan up and, as I was soldering, the solder reel shorted a part of the board. The screen went a bit crazy and the short lasted a couple seconds before I reacted.

Plugging in the 12v power supply now produces an audible buzz in the piezo speaker (the 5v on the RPi does not however). Everything seems to be working and I can log into the linkmeter software. The screen is fine too. On reboot after the short, the thermocouple was way off but reinstalling the software on the SD card seemed to bring it back in line even if it seems a bit less accurate than before.

However, upon further testing the fan will not stop even if the pit temp is above the threshold. Maybe I am not setting things up properly but my gut says something is wrong. I'm doing all my testing at room temp (~74f) with a threshold set below that.

Am I screwed or is there hope for this thing? I'd love to not have to order another kit! Unfortunately I have no access to a multimeter nor could I troubleshoot the components myself.

Thanks for any advice!

Set the blower to manual, and see if the blower responds to the percentage you set the heatermeter too.

Everyone is so quick to want to trash their board, this board is not that complicated, unless you have to pull a part like the shift register or LCD and muck up the traces in the process (and dont want to spend the time to add jumpers to fix it) there is no reason to toss a HM board and start over... You shouldn't be soldering on a board with the power on, that was your mistake, so you screwed up.... now lets figure out what died and fix it!

First of all, on the blower not spinning... I highly doubt the blower is bad because it runs on 12VDC and that's the highest voltage on the board, it can literally run right from the power supply. (So you can put the red wire from the blower inside the power supply plug and the black wire on the outside and it should spin like hell, no HM required) Now you know your fan is still good?

If the blower doesn't spin I would measure the output of the PS to make sure it is still putting out 12VDC... And there begins your troubleshooting at the DC power source... From there verify the 12VDC on the power connector on the HM board, then measure the 12vdc at the input of the OKI, then measure the output of the OKI for +5VDC, then look for +5VDC on the input of the 3.3v regulator and look for 3.3VDC on its output. That is your power supply.... If anywhere down that line you do not see the predicted voltage then you know where to start troubleshooting. It could be a bad regulator or a short elsewhere in the HM that is pulling the voltage down, your job would be to find it...

But I suspect your PS must be good, if you say the HM is functioning then 3.3VDC is present. Does the HM power up off of 12VDC when the rPi is not connected to it? (the reason I asks is, in the past the HM did not create its own 3.3VDC, the HM fed the rPi +5VDC and the rPi fed back 3.3VDC) I am not sure if the 3.3v pin from the rPi is dead on the HM header now or if the 3.3v is still being fed back from the rPi.... (Bryan?) Since you mention the TC being off after this event it made me wonder if something changed in your 3.3V supply after the short.... Perhaps the onboard 3.3v regulator died and you are now getting some 3.3v power from the rPi? So that is why I ask if it powers with the rPi removed...

Assuming all your power is there (since it boots and functions) and not knowing exactly what you shorted out, and hearing the blower runs all the time, I would tell you to look for damage in the blower drive and feedback circuits. But first of all, if this is a new build and you have never had it working 100% (able to adjust the fan speed with the HM) I suggest that you test the wires you are using for the blower in the CAT5 cable for continuity to the GND and BLOWER pins on the HM board CAT5 jack. Better to go by continuity than wire color or whatever, because not every cable has the same color wires.

I think that gives you much to chew on, dig into that and report back some findings, if you don't get it fixed in the process we will help you figure it out.... GOOD LUCK!

Thanks for the replies and sorry for the delay...just finally had a chance to log in now. So here is the update.

Manual mode does not make a difference. The blower seems to run flat out at 0% and 100%. The led lights up when >0% is selected so the controller seems to know that a signal to engage the blower exists.

I take total ownership over my stupidity in this case but am really hoping that I don't have to trash the board which is why I am seeking advice...and it is certainly welcome and appreciated!

The blower seems to be running very strong directly connected to the power supply and likewise connected to the board so I am not too worried about that.

Yes the HM boots up with the 12V (1.5A) connected with and without the rPi.

The TC seems ok. I just did a test with it and the three probes in my oven to 225. The probes didn't quite follow the same profile but they all settled on the same temp =/- 1 degree and the TC was about 5 degrees below.

As for the wire continuity, I should ask that I am making the proper connection first. I connect the blower's red wire to the 5V and the black wire to the GND. This is correct?

Lastly, I 3D printed and damper for my Vision Grill Pro C today. Excuse the serious ghetto tape job...I print at the library and they limit print jobs to 2hrs so I had to split the part up and tape together.

JohnS said:

As for the wire continuity, I should ask that I am making the proper connection first. I connect the blower's red wire to the 5V and the black wire to the GND. This is correct?

Click to expand...

Just give the above quote from your post a moment to sink in..... Blower Red Wire to 5V and blower black wire to GND.....
Ok, now that you have given that some thought you should realize that +5VDC across a blower to GND should produce a steady state situation with the blower just blowing however much +5VDC makes it blow....

You've got the gnd part right, just move the blower RED wire over to PIN5 on the HM board (labeled as BLOW) and you should be off to the races....

Ralph...simply put you are the man. She works a treat now. I still get a buzzing in the speaker and it changes volume and tone a bit when the CAT5 is plugged in. But I'll live with it happily if that was the worst that happened. Many many thanks for confirming I can be a huge idiot. Could you advise me on which wires to connect the servo?

Cheers!

You should refer to the schematic on the HM Hardware sticky for the basic CAT5 pinout.....
... here is the extended version I settled on, showing the servo, blower, probes and TC wiring for several versions of the HM...