Issue: Fan Speed switch to "off"


 
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Patrick Eggel

New member
Hi community,

i have sometimes the strange issue that my fan speed switch to [off] (not 0%). What does this mean? The HM also do this when the set temperatures is far higher than the pit temp... so he went to off when he should show 100%. Any ideas?

Jxgb7RN.jpg


Regards Patrick
 
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I had time to do some further testing. Soldering seems fine, but it doenst only happen on the left button. Most of the time the HM work as intended but sometimes it start to jump through the menu (random all button get "pressed). Any ideas?
 
I haven't had to troubleshoot the button board, but here is some general information about how the buttons work that may be helpful.

When pressed each button supplies a different voltage (determined by the value of the resistor connected to that button) to the same input on the ATMega , the voltage is how the HM knows which button has been pressed. If you are getting phantom button presses of various buttons perhaps you have some kind of intermittent short on the header between the button board and the main board? OR maybe even flux buildup in that area allowing voltage to leak over? I would inspect those headers on both boards well.

You could remove the button board and run without it, watching the web UI do you still have random button presses? This would give you a clue if the issue is on the main board or the button board.
 
unfortunately it also happens without the button board, i tested it few minutes ago. And no flux between the soldering points.
 
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It it happens without the button board attached, then I'd check the 1k resistor directly next to the pinheader riser that has the button signal in it. If this is making poor contact then it will let the button input float which will make random buttons happen. You can test by probing the BTN pin on the microcontroller with a multimeter and verify it has 0.000V at all times when no button is pressed.
 
I would say "fortunately" the problem persists with the LCD board removed, because that only leaves the base board to troubleshoot!

Consulting the schematic (posted below) you can see that the button circuit is quite simple. See the top right corner of the ATMega, Pin 23, BUTTONS. It goes up to R1, 1K resistor (to ground), then over to the LCD2F header pin 4 (where it goes to the LCD board).
As Brian said, the issue is most likely at R1 but could be at LCD2F or anywhere along the line of that trace on the board.

Buttons.JPG
 
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**** yeah, just from pushing the resistor the button "jumped" again, so this seems to be the problem. I will resolder it in the next days at work. My first soldering iron wasnt hot enough, i think that led to a lot of my problems.

Big thanks to both of you : )
 
Glad you pinned it down. If your soldering iron wasn't heating up properly during the build which resulted in this problem I would suggest you do a "shotgun" soldering of your boards just to make sure you don't run into other similar problems down the line. By shotgun I mean like scatter shot, go over the solder joints across the whole board and reheat and reflow a little solder so you know all the solder joints are well formed.
 
Glad you pinned it down. If your soldering iron wasn't heating up properly during the build which resulted in this problem I would suggest you do a "shotgun" soldering to your boards just to make sure you don't run into other similar problems down the line. By shotgun I mean like scatter shot, go over the solder joints across the whole board and reheat and reflow a little solder so you know all the solder joints are well formed. It'll only take a couple minutes but could prevent endless frustration if more cold solder joints creep up as you start using your HM.
 
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