pioneer vsx-d409

[Joust]

I have this problem with my receiver. pioneer vsx-d409

unit turns on.

After a few seconds the unit flashes "poweroff" on the screen and shuts
down.

switching seems to be fine, volume adjusts on the screen. the speaker output
releays do not engage.

AC relay is turned on. I can read dc voltage on the two large bridge
rectifiers

I do not have a service manual so I cannot say if it the correct voltage.

There is a fuse near the power amp section that gets no voltage. This is the
only thing I notice out of the ordinary.

One thing to note though. The fuse holder closest to the AC input was bent,
so that the fuse was very loose. The fuse was ok but maybe it causes
spikes????

Any ideas?

 

[Mark D. Zacharias]

The most common thing is a blown amp channel. Don't remember if yours uses
discrete transistors or output IC's.

Pioneers for the most part have no direct access to the bottom of the main
board. This would make a do-it-yourself repair rather difficult for most
people.

Mark Z.

 

[Joust]

this has two power modules.
is there a way to detemine if one or both is defective?
i can get into it. don't be shy on technical gotta do's

thanks for your help.

 

[Mark D. Zacharias]

OK, I'm going to try to look up the stuff. I'll get back to you.

mz

 

[Mark D. Zacharias]

There should be a .22 ohm resistor in front of each output IC corresponding
to each amp channel. Probably 5 watt, white emitter resistors. You can
measure the DC at these resistors. Whichever one has the big DC voltage is
your bad IC.

Be aware Pioneer also uses special little pico-fuses on many of these
models - you might have one or more bad.
I believe they're rated at 10 amps on your model. I only see one in the
schematic, but I could have missed something. It could be a regular fuse -
the schem doesn't say. The part number given here is REK1087.

The output IC's are pretty much only available from Pioneer. There is a STK
lot number on the back but generic suppliers wouldn't be any cheaper on
these - I've tried.

Pioneer's parts dept. number in the U.S. is:
800-457-2881. Try telling them you're with a servicer, you might get it
cheaper.


Mark Z.

 

[Joust]

very cool stuff.
Thanks a million.
you wouldn't have a scan of that schematic would you?

anyway here are my findings...
i found 5 pico fuses near power modules. all are good.
i found 5 0.22 ohm resistors near power modules. one near the large power
module PAC011A reads 65v on it. By this i assume that the output transistor
on that channel is shorted thus applying the full rail voltage to the power
resistor.

i think you found my problem. Pioneer charges $90 Canadian for this guy. not
a problem. i don't mind paying for good parts.
Thanks again.
B

 

[Mark D. Zacharias]

Glad that seems to have worked out for you.

mz

 

[Jim Davis Nature Photography]

i think you found my problem. Pioneer charges $90 Canadian for this guy. not
a problem. i don't mind paying for good parts.

I just bought a perfectly good, used Pioneer VSX700 Amp, with learning
remote on auction, for about 10 bucks. You might wanna check around.


Jim Davis
- checkout the Motorcycle Headlight Relay Kit at:
http://jimdavis.oberro.com/html/bike_acc_.html

 

[Andrew Hebert]

Hi Mark,

You didn't mention if you had a copy of those schematics available. I
am going to try to repair the same model of receiver, and those
schematics would be extremely useful.

Thanks a bunch,

Andrew

 

[Mark D. Zacharias]

Actually, I do have the PDF available, and as luck would have it, I'm back
to a higher-speed connection.
Post back if you want it and I'll reply direct with the attachment. It's
about 4 meg.

Mark Z.