To protect the new module, build a DBT. My own is even simpler than these, with no ON/OFF switch (less parts to break, in my estimation). A 100W bulb is appropriate. Ought to go bright, and quickly dim down as the big caps charge.
This is where I was a bit confused on the request...so I should leave the module in place and also install 1k resistors as specified?There was a way to test the amp board without the power module. With the module removed you can install a 1k resistor between pins 3 and 5 (of the power module), and another 1k resistor between pins 8 and 5 (of the power module). With 1k resistors the voltages at pins 3 and 8 should be +7V and -7V respectively. Sorry to be a little late on that suggestion. That said, I don't think that the power module is bad. I also think that this high offset voltage will not destroy the power module if there is no load. It is thus safe to keep the power module installed.
Did you compare the voltage at the zener De3, between L and R channel?
With this high offset voltage, Ce3 is probably bad now. I would replace Ce3 and it is a good practice to shunt the feedback capacitor with diodes, one diode in each direction. That prevents failure of the capacitor in situations where there is a large DC voltage at the output.
Can you measure the DC voltage at the collectors of Qe1, Qe2, Qe4 and Qe5?
Actually Qe7 is driven too hard. That pull the power module toward the positive supply rail.