MB Subway Rocket Overall Volume Seems Low for 20w

[g1]

The fet should only be engaging the contour feature, even if it was shorted, it should just make the contour stuck (on I think).
Sounds like they may have changed from -30/-15 supply to split +-15V supply, in which case schematic is not a match
What are IC voltages at pins 3,4, and 8 ?

[chunkitup]

I will be back on this amp tonight after work. Chasing the signal thru the eq section would help pinpoint the bad part, correct? I will also check the ic's. Do you think that the scheme is wrong and it should be -15v?

[g1]

Yes, tracing the circuit through the eq should find it. Is the contour switch working? (It may be a massive mid-cut and you are using 1K signal).
I mentioned the IC because it is easy to check the supply voltages. Normally IC's run on +/-15V split supply. This schem. shows -30 at pin4 & 0V at pin8, with -16V at pin 3 for ic bias, and -30 going to the EQ.
If the schematic is wrong and they are now using split supply for the IC, then there probably is no -30V, and the -15V at the eq may not be an issue.

[chunkitup]

IC readings. The IC is a NE5532AP which the data sheet states +-15v proving the scheme is different yet again.
Pin 3: 0v
Pin 4: -16v
Pin 8: +15v

I havent had time to chase the signal or check the headphone out. After work today.

[g1]

It sounds like they are using a split supply so I don't expect you will find -30V in the eq area. The IC is probably fine.
But I would expect the supply to be balanced better, like +/-16 instead of -16 +15.
Is the contour switch working?
In addition to your signal trace results through the eq, could you post all transistor DC voltages for Q1 to Q4 ?

[chunkitup]

Here are the transistors voltages.
Q1 C -16
B -10.7
E -9.9
Q2 C -15.7
B -9.9
E -9.4
Q3 C -16.3
B -9.9
E -9.37
Q4 C -10
B -15.6
E -16.2

When I replaced Q3 the original was MPSA70 and I used a PN2907 PNP silicon.

Also the contour switch does work.

I will trace the signal when I actually get more than 10mins to sit at the bench.

[Jazz P Bass]

The static voltages don't look bad.
Ideally, for a class A circuit the base should sit at 1/2 of the collector voltage.
As long as the input is not over 5 volts that circuit looks like it is ready for a signal.
That leaves the coupling cap (0.1/60V) & or the actual EQ circuit.

[chunkitup]

When I open an amp for the first time I always look for what is not from the factory. Flux from someone soldering new parts in and so on. That coupling cap stuck way out. It is the only 715p in the amp. Mesa does use orange caps but not in this amp. I am still at work but I am hoping I will find the problem there.

[chunkitup]

YEA!!! Last dang link in the chain. Of course the scheme is wrong again. Disregard the orange drop, wrong part. The coupling cap was 1uf not .1 and it was faulty. Replaced the cap and shabam! Nice and loud. Thank you so much Jazz and g-one. Kept me in the game when I wanted to destroy stuff.