8 Jun
2018
8 Jun
'18
6:04 a.m.
Aaron Jackson via cctalk wrote:
Difficult to repair? Probably since it is the worst switching PSU Desing
I ever meet, at least from seriveability and the mechanical point of view.
I own an 4000/300 with an working again PSU (after some capacitor
changes) and I habe an PSU from a friend here..its works sometimes,
mostly not.
Regards,
Holm
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On Thu, 7 Jun
2018, Aaron Jackson wrote:
Haha, okay, seems reasonable. I'll have to probe about a lot more
then. Not giving up quite yet, even though everything I have read about
this power supply has said that it is difficult to repair. So far, I
would agree with such a statement.
Thanks,
Aaron. The VAX turns on and the status LED stays on F.
The DC lamp does not
illuminate on the PSU. 5V rail appears fine but there is nothing from
the 12V rail. There were some *very* dodgy looking caps which I have
replaced, and some *very* exploded MOSFETs, which I have also
replaced.
If that's all that you replaced, no wonder it still doesn't work ;-)
Usually shorted power transistors in SMPSUs also break one or more fusable
resistors, maybe some diodes, maybe the driver IC or transistors.
So if you have anything that "exploded" in the power supply, be sure there
is more work to be invested that replacing the obious parts.
Christian