Hi all,
I have a problem with diodes constantly blowing out on my two Velleman MK138 thermostat kits. The thermostats are part of a 3D printer setup and are powered from the same PSU as the stepper motor electronics. My suspicion is, this is because of the current and possibly voltage surge during "power on". The schematics says, the input current should be 100mA. My guess is, the only purpose of the diode is reverse polarity protection in which case I could just jumper it. On the other hand, possibly the diode D2 failing is what protects the IC from disaster.
How can I limit the current to 100mA? Any other possible causes or solutions?
Schematics of the thermostat attached below.
Thank you all for your input.
Edmunds
I have a problem with diodes constantly blowing out on my two Velleman MK138 thermostat kits. The thermostats are part of a 3D printer setup and are powered from the same PSU as the stepper motor electronics. My suspicion is, this is because of the current and possibly voltage surge during "power on". The schematics says, the input current should be 100mA. My guess is, the only purpose of the diode is reverse polarity protection in which case I could just jumper it. On the other hand, possibly the diode D2 failing is what protects the IC from disaster.
How can I limit the current to 100mA? Any other possible causes or solutions?
Schematics of the thermostat attached below.
Thank you all for your input.
Edmunds
Attachments
-
157.9 KB Views: 47