Can't Adjust Idle Current to Spec

[mmartell]

Onkyo TX-NR636, blown right channel. Replaced output transistors and 5W emitter resistors in amp section and some small transistors and resistors on the preamp board. Can't adjust idle properly - turning the pot all the way up doesn't even get me to the minimum suggested starting point in the SM.

Before I move forward... can I isolate the problem using headphones ? ie, if it sounds ok through the phones the preamp is good and the amp section needs looking at ? Have not hooked up speakers and of course don't want to push my luck as the ouputs are still good

[mmartell]

Re: Can't Adjust Idle Current to Spec

I've checked all my work and everything looks good, so obviously I'm missing something lol. The pot itself measures good with resistance reading, btw.

Here are the schems of the Amp and Preamp board. Is there anything here that should jump out causing the Idle Current pot to max out at 1.5mV ? It should be set at 2.5mV to start and rise to 9-11mV after five minutes.

[mmartell]

Re: Can't Adjust Idle Current to Spec

R5371 on the collector of Q5251 (which I had changed) had drove itself from 2.2 ohms up to around 40k ohms. Replaced it and all is well.

[Tan44]

Re: Can't Adjust Idle Current to Spec

R5371 on the collector of Q5251 (which I had changed) had drove itself from 2.2 ohms up to around 40k ohms. Replaced it and all is well.

Amplifier's can drive us round the bend with setting things up, watch out for counter fake parts. over the years in this field I've serviced repaired many many amplifiers from crown macro tech's, ev p300's to valve amps all brain drainers.. still it's good you nailed it.. sometimes if you have a working channel use it to take ref points volts to nail that nagging fault. current draw can be done via placement of current meter within + or - rails idle would be set cross the emitter resistors and trim things that way and no loading of the amplifier with signal or speaker loads.