Vintage Synth Repair

Hello,
Have you checked the .22ohm 1 watt (1P?) resistor?
I just repaired a Yamaha CS40M that had that resistor out (.47 on the CS40M) and that was the cause of the -15 volt failure and the other voltages not meeting full voltage (+10 was +8 and so on).

Once I replaced that all came into full power.

Check those out.

GD


--- In vintagesynthrepair@yahoogroups.com, "cpt.zilog" <cpt.zilog@...> wrote:
>
> Hello guys and sorry to jump in like that but I would suggest to change the big caps as a priority and then check the bridge rectifier again for leakage of AC current.
> 
> I had a big problem with a D&R console's psu in which the voltage regulators kept on going Kapput. Turned out that the big Electrolytics were bad and that induced a big stress on the rectifier bridge, which in turn had the consequence of not only letting DC pass as expected, but also AC at the same time !
> 
> I did test for AC leakage on the rectifier after the newly installed voltage regulator worked for a couple of seconds before shorting...
> 
> After new BIG caps, new bridge rectifier and a 2nd new voltage regulator, everything was sorted.
> 
> Good luck !
>