Comment on Resistor Identification
blackbeans@lemmy.zip 4 days ago
69 MOhm is not very likely in a larger housing. Resistors can shift in value but they rarely break without any visual damage.
I would first check for broken solder joints on parts that get warm and check if the relay is performing as intended.
jeinzi@discuss.tchncs.de 4 days ago
Broken solder joints is a very good idea, thank you. I already found one earlier, but I haven’t resoldered them all yet.
The relay is not performing as intended. The circuit board is controlling an electrolysis reactor which works fine until apparently the pressure switch decides the H2/O2 pressure is high enough and it tries to turn the reactor off. At that point the relay goes brrr, switching on and off very fast, producing a lot of sparks, and it stops when the fuse blows. Deactivating the pressure switch “fixes” the problem, but that is dangerous in itself.
MrOtingocni@lemmy.world 3 days ago
Sorry for blowing up your thread but as for repairing it, might not hurt to draw up a schematic based on the board and try to ascertain exactly what the resistor is doing and why it is in the range it is in.
If it were me, I would separate out the pressure signaling system and see on which side the anomaly occurs. If you provide a solid signal and it still oscillates, the problem is probably in the main board. On the other hand, if a solid signal produces a one-off effect, the issue is in the pressure sensing module. Something is causing it to oscillate.
jeinzi@discuss.tchncs.de 3 days ago
Thanks for your tips :) I already finished drawing the schematic, this resistor was the last part I hadn’t clearly identified. Now I just need to understand it :D