Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "Scott Nordlund"
<gsn10@...> wrote:
>
> >News - I replaced the tantalum cap with one that can handle up to 25v
> >and disconnected the other boards from the synth, the cap has not got
> >fried at all, but voltages are inaccurate-
> 
> This doesn't necessarily mean the problem is entirely fixed unless you 
> verify that the transformer secondary voltages are okay.  If they're
putting 
> out more than they should, you may overheat a regulator once a load is 
> connected.
> 
> 
> >-15v read -14.6
> >+5v  read +4.25
> >
> >the +15v and -5v are adjustable so they're ok...
> >
> >What could cause the inaccurate voltages ? should I replace the 7915
> >and 7805 ? or maybe some particular caps ? or do they appear like
> >this because no board is connected to the PS ?
> 
> These regulators should work regardless of load.  If the input
voltages are 
> okay then you may want to replace them.
> 
> >Also, does this indicate that some other board shorts the -15v rail ?
> 
> not really, no
> 

Just a quick sense check - if all the voltages are reading low, and
the regulators are standard fixed voltage types - I'd have thought it
unlikely they are both in need of replacement - are you sure the meter
is reading correct? and check the ground reference point you are using?