[sdiy] Moog 909 power supply component ID question

[Gert Jalass]

Gene,

Mouser (in the US) being a good source any of the CJ stuff:

http://www.mouser.com/index.cfm?handler=fra_pdfset&dir=612&pdffile=505

Gert

----- Original Message -----
From: "Gene Stopp" <gene at ixiacom.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, December 04, 2002 8:27 PM
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 a DC fuse
> and back in to the power supply. (Aha! This is why the thing doesn't power
> up by itself on the test bench - you need to stick a jumper in the jones
> socket.)
>
> I am torn between three possible routes of repair:
>
> 1. Repair with new components
>
> This will take some time, since I'm not too good at discrete transistor
> power supply designs. This means I will probably use the "educated guess"
> shotgun troubleshooting approach, using a scope to verify passive
components
> and replacing active components. The problem here is finding replacements
> for 1965-era transistors. The advantage to this approach is that the 910
> will remain essentially unmodified and "vintage".
>
> 2. Rebuild with new regulators in existing 910 chassis:
>
> This means I will rip out the guts, leaving the chassis, transformer, and
> all associated jones sockets. I would add a full-wave rectifier and big
> caps, plus some new modern regulators mounted in the existing heatsinks.
For
> the +12 I would probably use an LM350 in a TO-3 case, and for the -6 I
would
> probably use an LT1033 in a TO-220 case. The -10 unregulated would come
> straight off the raw negative DC. The advantage of this approach is that I
> will feel a lot better about the power supply continuing to operate
properly
> into the 21st century. The disadvantage is that I would essentially
destroy
> a little piece of history.
>
> 3. Make a new power supply and shelve the 910
>
> This would be the same design as #2, all new stuff, with a new chassis (or
> block of wood) that fits into the same footprint of the 910. The problem
> with this approach is that I would have to go out and find all of the
3-pin,
> 6-pin, and 8-pin jones sockets somewhere. That plus all of the metal
bracket
> fabrication etc. Then fixing the 910 would become a rainy-day project.
>
> Questions to list:
>
> Any opinions on keeping the 910 "vintage"?
>
> Anybody know where to get all those jones sockets? I'll do a search, but
> short-cut help would be great.
>
> Best Regards,
>
> - Gene
>
>
>
> -----Original Message-----
> From: Michael Buchstaller [mailto:buchi at takeonetech.de]
> Sent: Wednesday, December 04, 2002 5:40 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Moog 909 power supply component ID question
>
>
> Hello dear list friends,
>
> for my 904A filter i have also built a clone of the original
> 909 power supply circuit.
> I had tu substitute the germanium output transistors DTG110
> with the more readily available ASZ17 - i think this should be
> no problem.
>
> But there is a Zener diode D6 whose value i cannot read.
> (it may be 1N821, but i am not sure)
> Which voltage should it have ?`
>
> Thank you all !
>
>
> -Michael Buchstaller