19 Aug
2006
19 Aug
'06
1:08 a.m.
On Fri, 18 Aug 2006, Tony Duell wrote:
I assume this is a schematic in the technical
reference or service manual...
Yes.
Be careful, In the case of the M3 (a machine which I
_have_ worked on),
the PSU was bought-in from ASTEC. ASTEC did not supply (or allow to be
publisehd?) their schematics, so it appears somebody at Radio Shack
reverse-enegineered the board to provide a schematic for the manual. And
Hmm, the power supply in the M2 was from ASTEC, too. But the technical
reference manual has an own chapter for the PSU with some bits of
information on how it works, but no parts list...
That said, I've found the 2SD1942 to be a good
'universal' chopper in
most small single-stage SMPSUs.
Does it come in a TO-3 case? The BU208(-A/-D) should be a good
replacement, too. Anyway, either it works or it doesn't, there's not much
to lose here. Of course the "repaired" PSU should first be tested with a
"safe" load (power resistors) to check the output voltages.
Christian