pioneer vsx-820k doa

[guitardad]

I have a VSX820k had blown channel in FR on main amp board. Took care of that problem, but unit will not start up. I have no sby light either. 3.3v to main cpu are ok, Sby power supply voltage is ok.

I read something about test modes, but this one will not enter any test modes. Otoh I am attempting this on a variac, but even at full AC in no sby indicators.

Any ideas?

Thx in advance.

[Jazz P Bass]

Did the unit power up before the repair?

The Service Manual can be found here: http://elektrotanya.com/pioneer_vsx-.../download.html

[guitardad]

No Power upon receipt of unit for repair.


That schem works out great! thanks!

had to hold ADV SURR button for 2-3 sec while powering up to reset unit. Cannot do the reset with unit on Variac. I guess this unit has several display modes that define any potential problems. It sure seemed like a standby power xfr or supply issue. Then I noticed a couple burns on the FP resistors on the Amp Board FR ch. 7 xistors (D2390, B1560, C3964, (2) 2SA992, (2) 2SC3200 and 6 [(4).47 2w, (2) 4.7 1/4w] resistors later it works.

Some of these transistors are hard to find. I have found them at HB Electronics out of Calif.

For those that run into this, the power light does not come on until the unit is powered. I was thinking it had a power sby light like many receivers do.

You can check just few things to see what's going on. By the power in connector to the amp board there is a jumper marked protect. If that line is 3.3v the amp is ok. If that voltage is low .6 or lower, then the amp board has a fault (any of 5 ch's). On the far right there are 3 other jumpers for test points. Vcc, CPU B+ and SBY ON. Cpu B+ should be 3.3v in standby. SBY ON is the return from the front board. Makes it easy to check.