Yamaha RX-V563

[irobot]

This one has me baffled -

I Have a Yamaha RX-V563, when plugged in all DC voltages seem to be OK. (Power relay energizes as soon as it's plugged in.)

Main ON/OFF button has no effect. Speaker relays do not kick in. FL display stays off, although voltages seem good on the controller, from about -24 to -29 VDC.

The LIM circuitry is functioning, when applying an external test signal.

This problem is very similar to a Yamaha RX-V361 that I'm servicing.

Both these units use the Sanyo STK433-03 and STK433-130 power amp modules.

Thanks in advance for any help !

Mike.

[jts1957]

[irobot]

Hi

Thanks for the reply. The power relay driver transistor is good.

The base has about 3 VDC on it as soon as power (AC) is applied, which of course, turns the transistor on and energizes the relay.

I traced the PRY signal. It comes directly off of one of the pins on the DSP (Blackfin) IC.

[jts1957]

Can you find which pin tells IC to output PRY?

[irobot]

The PRY signal comes off one of the I/O ports, pin 34 on the CPU/DSP. Normally it's at logic high (3.3V) right after power on.

[jts1957]

Well, does either (input or output) "toggle" along with your command to turn on (or off)?

[irobot]

Hi again -

After closer inspection, here's what I found:

All power supply voltages are OK with power relay bypassed.

Standby and System Off buttons do not power up unit.

Of course, no display, although voltages on FD pins and controller seem OK.

/PDET, /RESET, PRV1, PRV2, ACDET, VP, THM, PRD, PRI are all OK, although the LIM signal is missing.

Clock signals are all good throughout the DSP board.

Any ideas?

Thanks,
Mike

[Drdave]

I hate to say it, but it sounds like a bad Micro.