Vintage Synth Repair

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.  The schematic states 21V at the input to the
regulators, allow 1.5V for the volt drop across TWO rectifiers in series so
the required voltage should be 22.5V.  This is almost exactly .  I'm not
sure that the maths figure will reproduce correctly, but in words it is 15
time the square root of 2.

 

The only other thing you need to know is the power rating.  Given that the
input fuse is rated at 500mA and assuming 230V mains (as it is here in the
UK) the maximum power before the fuse should blow is approximately 115VA, so
a transformer rated at 100VA would be ideal.  It is highly likely that an
80VA unit would suffice.  The cost differential between an 80VA and a 100VA
is likely to be minimal so I'd go for 100VA provided there is sufficient
room in the box.

 

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Boddington
Sent: 02 June 2011 5:44
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Crumart Trilogy replacement power
transformer

 

  

I'm basing it entirely on the schematic.

I don't the believe that the windings are 12 & 15 as the message above
suggests. Those are only the outputs after the regulators have done their
job. You'll also find 9.1V & 6V as part of the rail. See for yourself. Let
me know what you think.

http://manuals.fdiskc.com/flat/Crumar%20Trilogy%20Schematic.pdf