Onkyo TX-NR5007 Protect Mode

[jbkiansiang]

Hi I am having problems with an Onkyo TX-NR5007 going into protect mode. I have experience fixing a few other receivers but I am struggling to narrow down the problematic areas to check for this one. The service manual can be found here:
https://elektrotanya.com/onkyo_tx-nr5007bs.pdf/download.html

Things checked/tested so far:
1. All output transistors seems ok.
2. Fuses are all intact.
3. All 3 Bridge diodes on PC boards seem ok.

Testing observations:
1. If i remove all the vertical amplifier pc boards from BAAMP-0191, does not trigger protect mode.
2. By connecting JL6041B wires individually, the signal triggering protect mode is coming from VPRO line. IPRO does not trigger.

Any help to filter down which areas to check or possible causes is greatly appreciated.

 

[73's de Edd]

Sir jbkiansiang . . . . .

That's being one very HEAVEE and complex hernia creating unit . . . with 8 sets of power amplifier output transistor sets and 8 amplifier / driver boards that requires 283 pages of repair documentation and schematics.

Herewith . . . . . . your simplified and UNITIZED schematic of its relevant protection circuit flow path.

Left top corner you have the YELLOW box 12 of the relevant Adobe page number if further researching is needed.
That initial referencing is being for the 8 amplifier and driver sections of the units 8 audio output amplifier boards.
The YELLOW box 13 referencing just below, is being for the 8 sets of POWER output transistors and 8 sets of small signal transistors that collect current---voltage and peak audio voltages to interface into the amps protection circuitry.

At the very bottom you see the three Current-Voltage and Peak lines that route from J6041B over to the right to the "mixmaster" at YELLOW box 14 . . . I have your line of interest . . . Voltage . . .being RED highlighted.

That sections Q6702-13 and 03 sort out your different faults and lines then exit down the RED path to bottom left jack 7210A and routes across the bottom to the right to YELLOW box 22 and enter companion P7210B and the RED line routes around to pin 130 of U / P U0041 where the shutdown action is done, if having a fault voltage routed to there..

PROBABILITIES . . . .

Check the POWER transistor sets on the POWER boards for any blatant faults, with those power transistor pairs, such as direct Collector -Emitter shorts or open Emitters.

If you unplug the POWER boards, be sure to mark them to keep up with their positions, as the companion driver boards have the mating idle current pots on them.

You could then have all of them unplugged, except for one, to see if that errant DC voltage is then being on the Voltage sense line, and then power down and add another board until the VOLTAGE shows up.
Then pull that bad board and then continue on with the rest.
You may / probably will only have one amp section at fault.

Thaaaaaaaaaaassit . . . . .

SIMPLIFIED REFERENCING . . . . .

73's de Edd
.....