[sdiy] Juno 106 power supply issue

[Travis Shire]

> Strangely my 106 power supply has suddenly started to read about 30v on 
> the negative and positive rails, instead of the normal +15v/-15v ...
>
> Both 500mA fuses got burnt when that happened, but I replaced them and 
> they do not burn now. The 9v rail shows zero voltage as well, but the 5v 
> is ok.
>
> Any idea what could cause this ?
>
> Thanks.
>
I had this happen on a Peavey MKIV mixer recently. In that design, the pos 
rail tracks the neg rail. The to-3 cased 7915 shorted and spit 
out -33v....the pos rail spit out 33v as well 'cause it was using the neg 
rail as a reference.