Peavey XR8600D power supply cycling

[Delta362]

What voltage should I be expecting on pin 5 (CSD) for the amp to pass a signal? What about the HV_SHUT_DOWN signal expected for normal operation? Do any of the voltages look out of place on IC102? Pin 1 to 2 is 6.57V. All others were with respect to chassis.

[Delta362]

I have good signal for INPUT_A and INPUT_B, but still no sound coming out of the power amp stage. Do the voltages on IC102 look correct, namely the CSD, HO and LO pins? As with my other post, I'm not intending to replace parts just to see if I fix it. I'm trying to understand how the IRS2092S chip functions and what voltages it is expecting. Then properly fix it.

[Delta362]

I applied an 8 ohm resistive load to Channel A and remeasured the voltages on IC102. The compensation input went to 0. The CSD is now at 0.18VDC. Vs is at 0, HO is at 0, VB is 12.6, and CSH is 3.9. The rest of the voltages remained unchanged. For Channel B, without the 8 ohm resistive load, I have the voltages that were on the prior posted schematic.

Signal is good from the preamp coming in on POST_VR_A and POST_VR_B. It then makes it to INPUT_A as well as INPUT_B. Any advise on what else could be preventing output for either channel? Thanks!

[x-pro]

Check TR100 for breakdown.
Is the track from R205 connected to pin 3/ IC202? Check with a meter.
Relative to GND_B4, pin 1 / IC202 should be 6.2 V. The same voltage should be on pin 6, but with a different polarity. There should be +10 V or so on pin 5 of the CSD.

[Delta362]

With an 8 ohm resistive load on both channel, I have 27.7VDC on the triac pin 2/pin4 (D46K). Triac pin 1 is 0V (chassis) and the triac gate pin 3 is 0.222VDC. D46A reads 0.164 for the HV_SHUT_DOWN signal.

I have +6.4VDC on pin 1 and -6.4VDC on pin 6 for both IC102 and IC202.

D101K is 0.164. D111K is 16.9. Diode D101A/D111A is 0.653.
D201K is 0.164. D211K is 16.7. Diode D201A/D211A is 0.820.

Pin 5 is definitely not getting anywhere close to 10V on it.

Edit: R105 to pin 3 is 0 ohm from one side of the resistor, and 3.3k from the other side of the resistor as measured on R116/IC1 pin 7 junction.
R205 to pin 3 is 0 ohm from one side of the resistor, and 3.3k from the other side of the resistor as measured on R216/IC1 pin 1 junction.

[x-pro]

Where does the "HV_SHUT_DOWN" signal from D201/D101 go, to pins 2 and 4 of IC3 in the power supply, or does it go to the anode of D15, D18?
You have to look at the voltages on IC3 in the power supply. Just to clarify, the availability voltages +80VNL & -80VNL.
Check all the elements around this IC for open circuit or increased resistance.

[Delta362]

Thank you for the guidance! I didn't notice HV_SHUT_DOWN on the other page of the schematic as I blindly only saw it by the triac. D40 was shorted near IC3. I didn't find any other bad components around IC3. After replacing D40, I had +5V on pin 5 of IC102 and had sound passing. For Channel B, I had +7V on pin 5 of IC202 and no sound.

While comparing the two channels, sound dropped out from Channel A. I saw that pin 5 of IC102 dropped to near 0 and was slightly unstable. After power cycling the amp, now the power supply seems to not kick start. Onto more troubleshooting...sigh...