Vintage Synth Repair

I suggest that you look at the schematic again - together with the page on
which the various circuit designations are quoted - you will see that the
ends of both secondary windings ARE in fact common and they are definitely
at ground potential.  It is also obvious that the outputs of the bridge
rectifiers and the transformer centre tap are connected together!

 

I stand by my original statement that a centre tapped transformer is
correct.

 

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Malte Rogacki
Sent: 03 June 2011 9:01
To: vintagesynthrepair@yahoogroups.com
Subject: RE: [vintagesynthrepair] Re: Crumart Trilogy replacement power
transformer

 

  

> OK I've studied the schematic and agree that only a single centre tapped
> secondary winding is required. As per your other reply a 15V - 0 - 15V
> secondary will suffice.

I'd go with two separate 15 volts windings! Contrary to most (but not all)
designs I've seen this power supply has separate bridge rectifiers for the
positive and negative rails. The two "inner" connections of the transformer
secondary are NOT connected to each other and are not on GND potential. It
is obvious that only the outputs of the bridge rectifier connect together
to GND.

I think it also has repercussions for the power rating of the transformer
but I would have to look this up in detail.