Mac SE/30 Analog Board: No 12V Power

[powellb]

I have an SE/30 that is recapped, and the analog board is also recapped (and reflowed) with a BabyFace PSU. I have mentioned that my horizontal drive has failed with the width being at least twice what the monitor can display. I've ordered an old parts analog board for the horizontal adjustment, but today I decided to replace the BU406 horizontal drive transistor before the other parts arrive.

The replacement went well. I noticed that the base and emitter sides of the circuit are always connected (Base goes to R18 and into T1), Emitter goes to GND. Collector goes to the flyback circuit. Once I had the old transistor out, I tested it, and it tested fine, so it wasn't the issue.

Put it back together, power it up, and nothing. Roughly every second, the fan would click and try to spin, but stop. No startup chime, nothing. I tested the power on the logic board side via the floppy, and there is 5V, but the 12V rail shows ~4V.

Any idea what happened? Did the BabyFace PSU fail?

 

[powellb]

Update: After disassembling everything, testing each component and finding no issues, I connected it all again, and now there is no problem. I guess it was just a weak connection before.

The transistor replacement made no difference in the horizontal drive, so the culprit is L1, L2, or L3 as the capacitors are new (though I will remove and test the ones in the horizontal circuit also).