Vintage Synth Repair

What kind of troubleshooting have you done so far on the PSU? Are you sure no voltage is coming form the transformer? The PSU isn't very complex. A dead short after one of the regulators could damage the regulator (I've had this happen before)Suspect electrolytic capacitors. 

Looks like there are a couple of fuses on the output of the rectifiers too. 

I've also seen bridge rectifiers fail, which I presumed was from a failed cap.

--- In vintagesynthrepair@yahoogroups.com, "duncan" <ferrograph@...> wrote:
>
> >>The schematics don't say anything in this regard (or am I missing something?)<<
> 
> the schematic I found by googling dates from 1981, & shows that the synth uses +/- 15V & +/- 12V as well as a couple of other lower voltages, all regulated on the power supply board. elsewhere in the synth there is some local 5V regulation.
> 
> http://people.su.se/~viklund/service_manuals/flat/
> 
> so..
> 
> you need to give it something that will do 15-0-15. a centre tapped iron core trafo that can do 15-0-15, or a dual secondary toroidal with two lots of 15V would do. somewhere on the back of the synth should be a power rating, though I would estimate from the schemos that somewhere around 80VA would be adequate.
> 
> you might want to change a few components, speculatively, in the power supply first. if the transformer really has been burned up, then there are other problems, most likely electrolytics or failed regulators.
> 
> hth-
> duncan.
>