Pioneer VSX-917V - standby blinking, no power

[FrozenHaxor]

Hello,

I'm attempting to repair this amp, but I lack knowledge about the hybrid amplifier construction ones. It appears to be in a protect mode judging by the blue standby light blinking, when I press it nothing happens, it just goes out for a second and starts blinking again. Tried some reset procedures that never work, and guess what, nothing happened

Not even a relay click like with most other units. How does the unit know there is something wrong when it doesn't even energize the main tranny?

There is clear and stable 5V standby voltage that does not change when trying to turn the unit on. Should I just short circuit the relay to see what happens? Would like some second opinion before blowing stuff up

Usually when this happens I start looking in the power stage, but this unit is very different and uses 2 integrated amplifier hybrids.

Perhaps there is some common fault with these?

The hybrids in this unit are SANYO STK-413-530 and STK412-530.

Photos of the amp:





Managed to find service manual for it.

[CapLeaker]

Re: Pioneer VSX-917V - standby blinking, no power

Read in that service manual page 133 & 134. Try that and post back what happened.
I think the problem for now the xprotect.
So the display ist saying anything at all? Like amp err, etc?

[FrozenHaxor]

Re: Pioneer VSX-917V - standby blinking, no power

Read in that service manual page 133 & 134. Try that and post back what happened.
I think the problem for now the xprotect.
So the display ist saying anything at all? Like amp err, etc?

Interesting find, that key combination of ENTER + AUTO SURR/DIRECT actually forced the relay to close, and I got an "AMP ERR" flash bfiefly, then it went back to protect mode.

Will investigate further, I see there is some info about diagnosing the hybrids (they call them "power packs" it seems).

[CapLeaker]

Re: Pioneer VSX-917V - standby blinking, no power

one or both of the hybrid bricks is / are gone.

[FrozenHaxor]

Re: Pioneer VSX-917V - standby blinking, no power

Initial measurements indicate that main amplifier power rails are not shorted:

IC601
Pin 2: 35,55V
Pin5: -35,6V

IC602
Pin 2: 35,5V
Pin5: -35,4V

IC603
Pin 2: 35,75V
Pin5: -35,5V

Will check the outputs of them according to schematic.

[FrozenHaxor]

Re: Pioneer VSX-917V - standby blinking, no power

one or both of the hybrid bricks is / are gone.

Actually there are 3 of them, I didnt notice at first. It's totally hidden under additional power regulator board and several flat cables.

[FrozenHaxor]

Re: Pioneer VSX-917V - standby blinking, no power

Looks like IC602 has a fault.

Pin 10 goes very negative when the transformer energizes (-28V) while Pin 9 stays close to 0V.

Pins 9 and 10 of 2 remaining hybrids have small voltage at start and immediately settle at close to 0V

Looks like thats the culprit.

[CapLeaker]

Re: Pioneer VSX-917V - standby blinking, no power

Well, I guess you found your trouble!

[FrozenHaxor]

Re: Pioneer VSX-917V - standby blinking, no power

Well, I guess you found your trouble!

Unit works fine after replacing the hybrid and restarting the protect mode. Thanks for the help with diagnosis!

[CapLeaker]

Re: Pioneer VSX-917V - standby blinking, no power

glad to hear that you were able to fix it!