Rotel RB991 with -61V on output terminals

Jaimo

Member
2005-10-18 11:51 pm
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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Jaimo

Member
2005-10-18 11:51 pm
RB991 Fusing

Each Channel has it's own pair of fuses - and I re-tested both channels' fuses in circuit and verified that the positive and negative rails are connected to the collectors of both sets of output transistors.

Thanks for the input.