Hello,
I just had a shortage on the connector to the extruder heater (on the pcb). That connector had been giving poor signal for a while, and a while back i removed the heatshrink to resolder these wires because i thought that was the problem. Later i found out it was the connector on the pcb (or at least the female part of it) that gave bad contact.
Lately i’ve started trying to fix my k8200 to finally print something on it. I got it to work and forgot I had these wires without heatshrink (they are hidden behind my pc monitor).
So half an hour ago i printed something and when i tried to start my next print nothing happened. I reconnected the printer and restarted repetier because i thought something went wrong with the connection. Then i saw the temps in repetier of my extruder and my heated bed both indicated 200°C. (while they were at room temperature). Then i wanted to reset the pcb and i saw the two wires without the heatshrink touching. The extruder heater connector has 2 burned pins now. Since i’m quite a noob with electronics i have no idea what’s all broken right now or how to test what’s broken and what’s not.
If i have to buy a new pcb that’dd be unfortunate but it’s my own fault, no big deal on that one. But i don’t want to be buying a new pcb if it’s not necessairy off course 
So if anyone knows how i could start solving this, please let me know
Can you post clear, high res pictures of your board please?
(don’t forget to disconnect the wiring, so the board is clearly visible)
Thanks for the reply
here is the link to some pictures of the board. flickr.com/photos/125067556@N03/
at the back side you can see in the bottom right corner that that solderingpoint looks darker than the others, on the close up pictures from the connector you can see that they’re burned
At the first glance i can’t see any serious damage.
The Mosfet for the heater still looks good. So do the traces.
Have you already tried to power up the board and connect it to repetier without the thermistors plugged in?
I just tried it and I got the printer to home itself, but that’s about it. I can’t manually move the axis, it saids: printer stopped due to errors, fix the eroor and use m999 to restart. (temperature is reset. set it after restarting.)
I’ll now try to unplug different things one by one to see if i can get the axis to move manually
Nope.
The axes won’t move without correct temp measurement.
The firmware protects the printer from fire by switching into safe mode
if the headbed or extruder report too high or too low temp.
But that sounds not so bad.
The board reacts without the thermistors, so it must be a fault in the thermistors itself or their wiring.
Don’t ask me how it happend, but everything seems to be working fine again.
When i re-attached the board to the frame of my printer i noticed that when i moved the board slightly it would go from 200°C on the measurements to 23°C. So i tried to figure out what was happening when i slightly moved the board like that. I think the power supply wires werent screwed in very tight anymore, i now stripped the wires a bit further and screwed these in better. This seems to have fixed the problem. Maybe the burned parts on the heater connector is caused by the female part of the connector not giving good contact. So I think I just need to replace this connector for safety and i’m good
Thanks for the help!
Nice to hear it works again.
Can be that the power supply had bad contact, but i’d suggest to check the whole thermistor wiring again.
The ribbon cable is likely to have trouble with intermittent short or open circuits.
Anyway, happy printing!
