Vintage Synth Repair

Hi,

I started with the power supply but gor problems already there. I replaced the voltage regulators. When I tested the power supply aftwerwards, the -12V rail shows -14.60V. What can cause this, is the new 7912 bad? When I remove power from the power supply the voltage of the 7912 decreases and stays on 12V for a while. Seems like the new 7912 can't handle the input voltage?

--- In vintagesynthrepair@yahoogroups.com, "Lorne Hammond" <lhammond@...> wrote:
>
> Photo the heck out of it before or during disassembly (I know too late) for
> when you realize one went in backwards because you were tired and you can't
> find the polarity mark on the board.  Also I would replace all power
> regulators if you are going that intense as they take a lot of heat and wear
> and tear.  Lorne in Canada
> 
>  
> 
> From: vintagesynthrepair@yahoogroups.com
> [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Mikael
> Sent: Monday, May 20, 2013 5:52 AM
> To: vintagesynthrepair@yahoogroups.com
> Subject: [vintagesynthrepair] Re: Envelope problem, pops and "sensitive"
> pots (Crumar Composer)
> 
>  
> 
>   
> 
> Thanks for the answer. :) I have disassemled the synth completely and I'm in
> the process of mapping out all the capacitors I need. There are about 100
> electrolytics in this synth, hopefully I will not break anything in the
> process of replacing. I will let you know how it went later. 
> 
> --- In vintagesynthrepair@yahoogroups.com
> <mailto:vintagesynthrepair%40yahoogroups.com> , "65 Lotus" <Lotus@>
> wrote:
> >
> > I'd do a full recap of the electrolytics and see what you get.
> > 
> > It may not be the most scientific approach, but...
> >
>