zigzagjoe
Well-known member
So, I'm in the process of fixing up two SE/30s that I haven't played with for 18 years.... one is the favorite, and has 128MB of RAM and an ethernet card. So I want to get it 100% internally. I did a full recap job on that one, where the second is being kept as a control as the analog board and original PSU seem OK (for the sake of testing).
So: the CR-44 from that unit was fully recapped and some trivial load testing looked good. Put it in either unit - nothing. Brief pop from speaker, no fan or power on any connectors. Nothing connected but the motherboard and speaker, no drives...
PSU Tests OK outside the units. Even load testing to 75% on each rail simultaneously outside of the unit showed no problems, voltage regulation looks great. Put inside units? Nothing. Acts like overcurrent protection is being tripped, though I'm not even sure if these have that. Unfortunately, I neglected to test it before recapping.... so maybe it was bunk beforehand?
Long story short - skipping a lot of troubleshooting - I was about to give up and post here for help. Taking some pictures of the inside, I noticed I left out the thermal pad on IC252 (big transistor, looks like it's for 12v disk rail per schematic) during reassembly. Put it back and problem solved. I have no idea how it passed load testing if that was truly a problem, but I have no desire to take that power supply back apart for the 6th time to confirm....
Hopefully this helps someone....
So: the CR-44 from that unit was fully recapped and some trivial load testing looked good. Put it in either unit - nothing. Brief pop from speaker, no fan or power on any connectors. Nothing connected but the motherboard and speaker, no drives...
PSU Tests OK outside the units. Even load testing to 75% on each rail simultaneously outside of the unit showed no problems, voltage regulation looks great. Put inside units? Nothing. Acts like overcurrent protection is being tripped, though I'm not even sure if these have that. Unfortunately, I neglected to test it before recapping.... so maybe it was bunk beforehand?
Long story short - skipping a lot of troubleshooting - I was about to give up and post here for help. Taking some pictures of the inside, I noticed I left out the thermal pad on IC252 (big transistor, looks like it's for 12v disk rail per schematic) during reassembly. Put it back and problem solved. I have no idea how it passed load testing if that was truly a problem, but I have no desire to take that power supply back apart for the 6th time to confirm....
Hopefully this helps someone....