C4S Install for S.E.X. 3.0

[Doc B.]

If you replaced the signal wires and signal does not pass through those wires the problem is related to the wires. Either they are not adequately soldered or they are miswired somehow - either open or grounded. Signal tracing would be the best way to track down the problem. A scope is the best way to do that, but you can play music through the amp and use a DVM set to a low AC volt scale and look for a varying voltage that would indicate a music signal playing. Start the beginning of the cable you replaced and see if you find signal.

[wdavis009]

Yes, that was my thinking also so I replaced the Cardas cable with the original CAT5 wiring last night but no change in results.

[Doc B.]

My suggestion still seems relevant regardless of the current type of wire used. It's usually best to try to correct problems with a minimum of disturbance to the circuit rather than subjecting the connecting points to a lot of disconnecting and reconnecting. Tracing the signal is a non-invasive way to localize the problem point.

[Paul Birkeland]

My normal suggestion would be measuring a 60Hz tone as it plays through your amp, but the statement about having absolutely nothing at the headphone jack narrows down the problem area to the wiring between the output transformers and the headphone jack or the output transformers and the tubes. 

[wdavis009]

Measurements were approximately:

RCA Center Pin: >0.03xV
A8/B8: >0.03xV
A3/B3: >0.5xV
3U/17U: >7.0V
OT Output Tab: >0.15xV
Headphone Jack: >0.15xV

And I figured out the problem. Will go hide in shame now.

If you replaced the signal wires and signal does not pass through those wires the problem is related to the wires. Either they are not adequately soldered or they are miswired somehow - either open or grounded. Signal tracing would be the best way to track down the problem. A scope is the best way to do that, but you can play music through the amp and use a DVM set to a low AC volt scale and look for a varying voltage that would indicate a music signal playing. Start the beginning of the cable you replaced and see if you find signal.

[Doc B.]

No need to hide in shame if you figured out the problem. That's called learning. We approve!