[sdiy] Moog 909 power supply component ID question

[Lincoln Fong]

Here's another coincidence: A year ago I aquired a Moog 910 power supply
in a box of junk. It all appears to be intact. The best thing about it
is that it has 'July 1968' stamped on the side. I have no way of testing
it (though I could test the output transistors if they're what's needed)
though I suspect that since it's minus its synth, it may have been
replaced by the original owner. Still it comes with all the hardware
(metalwork a bit bent) so if you want it its yours for the price of
shipping. Bear in mind that I'm in England so it may be a 240V
transformer. Still I could remove that and save on the shipping. The
moral is never throw anything away I guess...

Lincoln

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Gene Stopp
Sent: 04 December 2002 19:28
To: synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Moog 909 power supply component ID question


It is 1N821: 5.9 - 6.5 volt, 75ma, 15 ohms

Coincidentally I am in the middle of debugging a dead 910 power supply.
I've got an old old original operation and service manual, and I can see
by the datasheet for the 910 that it was designed in 1965! The
difference between the 909 and the 910 is the 910 has an extra output,
which is -10 volts unregulated which is only used by the 901 and 901b
oscillators. It's interesting in that the +12 and -6 bipolar outputs are
NOT based on center-tapped full-wave-rectified positive and negative raw
DC sources. Instead, the half-wave rectified secondary goes across a
single big cap, with the positive side being the +12 output, and the
ground and -6 outputs are controlled by the TO-3 pass transistors
(Germanium PNP!). The negative side of the big cap leaves the power
supply first, going out to