Rotel RB991 with -61V on output terminals

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I have a Rotel RB990BX power amp with both channel outputs sitting at -61V. The voltage across the main reservoir caps is +- 66V.

I have in circuit tested all output devices, the driver tranny and the 1N4003 diodes that sit between the output and voltage rails and all these components check out okay. The Emitter resistors and Rail fuses also check out fine.

Any ideas what could be blown, resulting in the negative Vout?

RB991bx output stage.jpg
 

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OK. So the next thing I'd do is check the voltages at the collectors of all the output transistors. If these do indeed show up as +/- 66V then the problem is probably earlier in the signal chain. Are the input and driver stages fed via the same fuses as the output devices?
 
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