At my wits end with this Ross Compressor (AKA I need help)!

Started by pbrommer, July 13, 2006, 12:10:13 AM

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pbrommer

Sorry to bug you guys, but I'm thoroughly exhausted trying to track down the issue with this Ross Compressor. You guys have given me so much help in the past (much thanks - it helped me find the problem with my Tonemender!), so I ask for your help again. Here's the information.

Circuit: Ross Compressor/Saffron Squeeze
Schematics: http://aronnelson.com/gallery/SteveC/saffron2 AND http://www.geofex.com/PCB_layouts/Layouts/d&rpub.pdf
Layout: R.G.'s PCB layout (etched by someone else)
Changes: See the Saffron Squeeze for the changes. Many of the 1uF capacitors have been changed to 33uF. No changes to the voltage divider (56k/27k). Input caps are 100pf and 27nF with a 1M pulldown resistor. Installed Mark Hammer's recovery switch along with a 1uF electrolytic in parallel (like the saffron schematic). Have touched up all solder joints and checked the traces for continuity.
Problem: No sound at all. Bypasses just fine and the LED lights up. Did work about 6 -8 months ago, but very farty and the sustain pot didn't like to work correctly (thinking bad solder joint).

Now what you really need: voltages.
Source: 9.46V from OneSpot Adapter (best $30.00 investment I've made)

NOTE: none of the transistors have been installed as of yet!
Q1
C -- 9.45V
B -- 0.46V
E -- 0V

Q2
C -- 9.45V
B -- 0.55V
E -- 0V

Q3
C -- 9.46V
B -- 9.31V
E -- 0V

Q4
C -- 9.36V
B -- 0V
E -- 0V

Q5
C -- 9.30V
B -- 0V
E -- 0V

U1
1 -- 0V (no connection)
2 -- 4.91V
3 -- 4.96V
4 -- 0V
5 -- 0.11V
6 -- 0.55V
7 -- 9.46V
8 -- 0V (no connection)

The biggest issues I see are:
1) problems with Q1 and Q2 -- I can't seem to get the voltage down to the voltage charts at fuzzcentral.
2) Pins 5 and 6 of the CA3080E are way off and I can't find the problem. I've tracked it down on the traces, and nothing is showing up..

If you can help point me in the right direction, that would help. I've searched the archives, and haven't found a solid answer to the problem. You all are a great resource. Thanks in advance for the help. Take care.

Patrick
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pbrommer

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