[analogorgans] Re: Rodgers Specification 990
- From: "Doug Carlson" <Douglas.Carlson@xxxxxxxxxxx>
- To: <analogorgans@xxxxxxxxxxxxx>
- Date: Sun, 30 Dec 2007 11:43:44 -0500
Hi -
I have a 770 and had a very similar issue. Some lights worked - but no
sound. I measured all the voltages on the power supply and found one leg
was dead - don't remember now but may have been the 12 or 15 V line. I
traced back to a blown "pico fuse" - a soldered in fuse that looks like a
resistor - put a new one in and like magic everything worked again -
So, I would get the back cover off and start probing the power supply and
see what is coming out ....
Doug
-----Original Message-----
From: analogorgans-bounce@xxxxxxxxxxxxx
[mailto:analogorgans-bounce@xxxxxxxxxxxxx] On Behalf Of Bernie Arcand
Sent: Sunday, December 30, 2007 9:17 AM
To: analogorgans@xxxxxxxxxxxxx
Subject: [analogorgans] Re: Rodgers Specification 990
Walt, I don't know how similar your 660 power supply is to my 220, but it
more than likely is a multiple voltage supply...mine (Cambridge 220-II) has
+15, -15, +12, -12, +5, -5 (all DC). (All are marked on the supply) My
+12
volt portion went out..caused when I was troubleshooting a cipher, having
the probe slip and short a trace to ground, which cause a trace on the power
supply circuit board to fry open, a pass transistor to fail and a resistor
to burn up. I don't suspect that on yours, but it would pay off to know
exactly what your voltages are, as measured right out of the power supply.
If any one is off by 2 or 3 volts it causes problems. I removed my power
supply to work on it (all connections are marked...make a map), then when
fixed, I plugged it in and set the 12 volts adjust to 12 volts dead on.
Upon re-intsalling the power supply, the organ didn;t work.....because the
voltage was lower than 12 volts when under load. So I reset for 12 while
under load, and it has been working great since. Good luck, and let us know
what you find.
Bernie in ND
----- Original Message -----
From: "Walt Scrivens" <walts@xxxxxxxx>
To: <analogorgans@xxxxxxxxxxxxx>
Sent: Sunday, December 30, 2007 6:38 AM
Subject: [analogorgans] Re: Rodgers Specification 990
> This is just to embellish on my last message which was a kind of general
> "Thank You" to the group, here is what I've gleaned so far...
>
> When the organ quit working our organist called the man who does
> occasional repairs to it and the pianos. He indicated that the organ had
> a "bad power supply" and was not worth repairing. That only serves to
> challenge me! Having worked with power supplies from my ham radio days,
> and in TV and computer repair, etc. I am generally familiar with the
> power supplies of 30 years ago, so I volunteered to "have a look"
>
> The amplifiers are in a separate closet, plugged into a live 110v.
> outlet, and when the console is turned on, the amplifier power
> transformers are humming happily, and the heat sinks on the power
> transistors are warm.
>
> The lights on the console all turn on, and there is a key switch for
> "oudoor" speaker selection. Unlike the main power switch, the bezel
> around this switch does not light up, and when you turn the key, if feels
> as though nothing is connected to it. Definitely something to
> investigate there. The Operator's manual, which I have, indicates that
> this is for an Outdoor Tower Speaker system, which I'm pretty sure we
> don't have.
>
> Good news about the voltages being stenciled onto the PC boards. That
> will be useful when I get the back off the console (I assume that's where
> the tone generators are located!)
>
> Thanks for the pin-outs on the cables. Once we get this thing working
> again, it might pay to replace at least the audio cables. They may be
> original to the organ, and at least they would date to its installation
> about 25 years ago (we are not the original owners of this instrument.)
>
> Since NOTHING works (except the pilot lights) I'm assuming the defective
> module is in common to all - if it is a power supply would there be one
> power supply for all the circuitry within the console (The amps each have
> their own)?
>
> I'm assuming that the organ does not have any kind of protective
> circuitry that would shut down everything for a particular fault.
>
> I may go over to the church this afternoon, or possibly Tuesday. I'll
> get back to the list with a progress report!
>
> Again, many thanks to all of you!
>
> Walt
>
>
> This list is provided by Frog Music Press at www.frogmusic.com.
>
>
>
This list is provided by Frog Music Press at www.frogmusic.com.
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