Vintage Synth Repair

Yep, no actual problem with the synth itself. I just feel that it 
would be generally better for the circuit to run on the correct 
volatges. It could be a little distorted as well I think....
The voltages are read when PS is not connected to the other units.

Will reaplcing the transistors do the trick ?




--- In vintagesynthrepair@yahoogroups.com, Philip <eggwheatis@...> 
wrote:
>
> 14.4 volts I would say wouldn't cause you much of a
> problem anyway. It's ususally not critical. If it was
> the the +5 we are talking about then it would be
> different. It's common for psu voltages not to be
> exact even from brand new. Do you actually have a
> problem with the keyboard? 
> 
> If there is no problem with the keyboard I'd just put
> it back together and leave it.
> 
> If there really is a problem with the synth then maybe
> swap out the two transistors. If still a problem then
> it's probably not the PSU but something in the synth
> circuit that uses the +15-15 dragging the PSU down..
> 
> 
> 
> 
> --- gil_we <gil_we@...> wrote:
> 
> > I've just refurbished my JX8P's power supply unit,
> > replacing all caps. I check the voltages and see
> > +14.40v and -14.40v instead of -15v and +15v.
> > 
> > The schematics shows a M5230L dual tracking
> > regulator, two 
> > transistors and an array of resistors.
> > 
> > So far I replaced the regulator to no avail,
> > and verified the correct values of the various high
> > precision 
> > resisotrs in the circuit, which are found to be ol.
> > 
> > I'm trying to figure out what could be causing this
> > problem,
> > can anyone help ?....
> > 
> > Here's JX8P power supply schematics:
> >
> http://www.fileden.com/files/2006/10/13/285304/jx8p%20ps.JPG
> > 
> > ..and here's M5230L datasheet:
> >
> 
http://www.ortodoxism.ro/datasheets/MitsubishiElectricCorporation/mXqy
> > yxt.pdf
> > 
> > Thanks in advance !
> > 
> > 
> > 
> 
> 
> 
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