The power suppl filtering caps are 1,000 uf, factory calls for 470, is that where I'm picking up the additional voltage? I also have 16 volts AC on the secondaries...
Try putting a 100 ohm 1/2 or 1W resistor in series with the transformer center tap connection to the PC board. Guessing at the value based on the Ic of the op amps. It may need to go higher than that.
Lee, I've had good luck with the +/- 12VDC or the +/- 15vdc power supply modules I had built up for the Carver/PL Preamps. Maybe something you want to try. I haven't looked at the Power supply for the unit you are working on. It's got the built in regulators on the boards I built with heat sinks.
I noticed that some of the older units had Service Bulletins changing the transformers to 12 volt and changing some opamps and mods to the power supply to work with the new transformers so check all the Service manuals for the unit to see if anything has been done like that. I just had a Pre in that had SOME of the mods done, and some NOT done.
Lee, the voltages you measured were with no load (no IC's). I would try a quick voltage measurement with the IC's installed to load the power supply a little bit. The voltage will probably come down a bit.
Lee, I've had good luck with the +/- 12VDC or the +/- 15vdc power supply modules I had built up for the Carver/PL Preamps. Maybe something you want to try. I haven't looked at the Power supply for the unit you are working on. It's got the built in regulators on the boards I built with heat sinks.
Lee, the voltages you measured were with no load (no IC's). I would try a quick voltage measurement with the IC's installed to load the power supply a little bit. The voltage will probably come down a bit.
The center tap is just the easiest Lee, either works. When you put them in the 12V legs, you have to double the value (200) to get the result I was looking for in the center tap with 100.