rowe ami r91 no amp output

[kestrel165]

Hi
Can anyone help I have amp number 6-01139-02 fitted with pre-amp board 60792505. I have no output from the amp. I have done the checks in the manual specifically the one for the pre-amp output check and the driver output check (checking for 1V AC and 16V AC respectively) and both these checks fail. I powered up the amp on the bench and did some investigation on the pre-amp board, I found that when checking the output pin on VR1 voltage regulator I had the -12.6 volts expected but the output of VR2 is sat at -5v when it should be +12.6. Trawled the net and found that the ref voltage between Vout and ADJ on the regulator should be 1.25 volts, again VR1 checks ok but VR2 shows -0.2V. It appears that this Vreg is shot. would this cause the problem of no sound at all. I did the checks with the wire links to the pre-amp +12.6 volt buses in place, tried it with them out and got zero oputput from VR2
Any help would be appreciated there doesn't seem to be any spare pre-amp boards available at the moment.
Thanks
Ron

[kestrel165]

Hi Problem now sorted the VR was defective on the pre-amp, got a new one from RS components (56p), put it in and now all is working.