so I have a yamaha HTR-6030 amplifier, getting error PRD PRT 89 when i start it up in diag mode. unit only powers on for 3 seconds and shuts down, unplug required in order to power on again. This is the same unit on which I was getting error PRV PRT 161 (bad voltage to IC 161), I have replaced the bad -12v voltage regulator. am now reading correct voltages going to IC 161. Now I am getting this second error code which looks like its DC output error, I'm assuming part 98, could not find a part or IC 98 on schematics. there is a pin 98 on IC 161, looks like it goes to a right rear surround rca input, couldnt find anything wrong there.
I found this on another forum:
No, that is the full diagnostic mode. The diagnostic mode will not tell you which component is bad or which channel is bad. You have to determine that yourself. The PRD error means that either a channel is bad, the dc detection circuit is bad or the CPU is bad. 99 times out of 100 it is the channel that is bad. Connect a voltmeter to each of the amplfier outputs on the pc boards one at a time and power the unit on. Look for the output coils on each channel. They will look like a 3/4 inch high coil of bright copper wire. There should be one for each of the amp channels in this unit. Connect the probe to the silvery part of the coil that goes through the board. This is the output of each channel. Turn the unit on normally and observe the meter reading during the 3 seconds that the unit stays on. You will see the voltmeter settle down to nearly zero on the good channels. The bad channel will have more than a half a volt but more likely the full rail voltage on its output.
So i tested the five coils he talking about (I have included picture to make sure im in the right spot). all 5 peaked at about 3.3v then settled to 500-600mV within 2 seconds.
trying to figure out where to go from here, hoping someone who has more experience repairing amps could save me some time. Based on this guys post it sounds like its either the DC detection circuit or CPU (I assume that IC 161)
I'm assuming its IC 161, when the voltage regulator went out, it was putting out the full -18v instead of -12v to Q165 which was then supposed to knock it down to -7v for IC 161, when i tested at the transistor Q165 i was getting 1.4v I think before I replaced the regulator, but I was thinking maybe when the voltage regulator went out IC 161 had to much voltage for a period and it burned something out inside there?