After the recap of a Sony PSU for my SE/30, the Mac won't start-up (no chime, no fan). The analog board is known working. Here are the readings from the idle PSU:
View attachment 70694
I wonder why the -12V is so low. Any thoughts on that? Would adjusting "VADJ" at position 251 correct that or just increase it for all other voltages?
- Chris
By idle PSU, do you mean with nothing connected? As it is expected for the measurements to be all over the place if there's no load. You should have it connected to the AB and LB before measuring.
That said, no fan indicates something very, very wrong as the fan runs directly off +12v. What you may have done is forget the little electrically isolating thermal sheet between this transistor and the casing. If I recall correctly, without that sheet you have connected ground to +12v, which will test fine when the PSU is not installed in the machine. However, once installed in the machine you'll have earth ground
= +12v
= psu negative, in effect shorting the +12v rail and causing PSU to protect itself/not power on.