Onkyo TX-930

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Hi, I don't know if this is the right forum to post in so if not, please let me know which other one I should try!

I have an Onkyo TX-930 receiver/amplifier that's worked great since I bought it in '93. It doesn't get daily use but I did use it a couple of weeks ago and it was fine. On Sunday night I tried to use it and it wouldn't work.

Not sure how many other models and/or brands do this, but it has a "Main power" button and a "Stand by" button. When the "Main power" is pressed to on, the unit goes to stand by and there's a light that comes on labeled, appropriately enough, "stand by". Then when the "Stand by" button is pressed, the unit comes on as well as anything else plugged into it (i.e. CD player, cassette deck, etc).

Well, the Main power button seems to work ok because the unit will come on into 'Stand by' like it always has. However, when I press the "Stand by" button, nothing happens. The unit doesn't come on.....the light doesn't blink.....nothing. Same if I try to turn it on via the remote...it won't come out of "Stand by".

Of course Onkyo says I have to take it somewhere to be looked at but I'm not interested in shipping it to Charlotte, NC or Syracuse, NY which are my closest centers.

I feel like it's something simple. The only fuse I can find inside is perfectly fine. It's not blown and if I take it out, nothing happens when the Main power button is pressed. Which would be expected. I cannot find any sort of 'reset' button anywhere.

It seems very strange that this just suddenly would have happened with the unit sitting on the shelf it's been on for years. I don't think it got fried from an electrical surge because I would think the Main power button would do nothing in that case...and the fuse would be blown....and I'd think everything else plugged into the power strip and/or the back of the receiver would have problems too, and none of them do.

Does anyone have any ideas at all?

Thanks for your help,
Matt
 
Sounds like a soft-logic power up. . .The power is always on so
when you push the button it throws the mains on. . .Had a JVC
do the same thing several years ago. . .Wired around it. . .too
complex of a logic circuit. . .

Leaving it off for an extended time may reset the circuit. . .but
be ready to modify it. . .silly to pay for a repair on a unit as old
as it is when the rest of it works well. . .

The fuse most likely protects the main part of the amp . . the soft-logic
circuit is always active and not very well protected from the bad
stuff lurking on your AC mains.
 
Thanks for the replies guys. I'm going to leave it unplugged like you've suggested. I agreee it's a long shot as I've had it unplugged for at least an overnighter.....but it certainly won't hurt for it to sit unplugged longer than that.

I haven't ever done any rewiring inside a component like this....I know it ain't rocket science and I know I can learn how, I just don't know what would need to be done at this point to accomplish it. I hate the idea of getting rid of it or paying someone to fix it when it seems like it's got to be as simple of a problem as what you've described.

Are there any web pages or anything that you can point me to that might explain how to go about wiring around the circuit?

Thanks a bunch for the help,
Matt
 
Pull the lid.

Take some good photos. . .

Upload them. . .

We'll take a look. . .

We'll give you advice. . .

You will do the work. . .

Your amplifier will work. . .

The 'leave it unplugged' method works if left unplugged
for long enough. . .I have a 200 CD changer and it takes
about a week to forget. . .
 
Onkyo TX-930 pics

Sorry I didn't see your post sooner......I'm not reciving the email notifications and I forgot to go look for replies.

Anyway, I've attached ONE picture.....I can't seem to meet the measly 102400 bytes size restriction if I put more than one picture in a zip. So I hope it's the one you need to see. If not, please let me know and I guess I can post each one separately.

I also found the service manual here:

http://www.eserviceinfo.com/downloadsm/30342/Onkyo_TX-930.html

It says that it's a multi-part manual and there is a TX-930.part1.rar and a part2.rar.....but the part2.rar never opens and the pdf that extracts out of the part1.rar looks pretty complete to me.

The pic I'm guessing you need to see is of the main card with the little stand-by part that hangs off of it. I think I've got decent enough picture of it.

So, whatever guidance you can give me would be great.

Thanks for the help!

Matt
 

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I just downloaded the service manual.

Just read a little. . memory is 3 to 4 weeks. . .that is for settings. . .
could work for logic circuit. . .that is a long time to wait. . .

When the main power is on. . .the logic circuit is live. . .

Does the remote turn the unit on?

Might be a bad micro-switch. . .put a ohm meter on the terminals
with the plug unplugged. . . .put the button. . .the ohms should
change. . .
 
I hope it is only a bad switch. . . I would focus on the switch first. . .

It is a momentary contact switch. . .if that doesn't turn it on. . .
the controller chip might be bad. . .it is so integrated. . .my old
JVC receiver had a board separate and was easy to bypass. . .

I hope it is just the micro-switch.
 
Hi Chris,

Thanks again. I hooked up my meter like you suggested. The Ohms do change when I press the main power switch. You can see in the attached photo.

The remote will NOT turn the unit on.

I assume by "Soft power on switch" you mean the itty-bitty stand-by board that hangs off the left side of the main board in my previous picture. I don't know of a way to test it and it doesn't just unplug, it's soldered on both ends of that ribbon cable. I also haven't found anywhere that I could order a replacement part so if you or someone else out there knows of a place, that'd be really swell to know too.

Was that picture I posted yesterday what you needed to see? Is there something else? I didn't think the board where the power cord comes in and the one fuse is located would help...nothing goes from that to the stand-by switch. Being an extreme novice on this sort of thing I obviously don't know the answer....but it seems to me like the bypassing might could be as simple as attaching a little wire from one side of the stand-by switch's soldered connection to the other side (on the same stand-by board). Only thing is there's three wires/connections in that cable.

Maybe it's not that simple? On the plus side, a buddy of mine has a Pioneer receiver/amp that he no longer uses with these same capabilities as my Onkyo that he said I could have. I just still feel like it'd be a huge waste to just pitch the Onkyo if I can fix it semi-easily.

Thanks for the help Chris,
Matt
 

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Being stuck in standby could be anything. It could mean a fault with the microcontroller. It could be a power supply issue. It could be a protection circuit stopping the amp coming on if something is wrong.

I dont want to sound harsh, but really this is not the sort of problem you can fix without some experience. Sorry.
 
My original hope was a bad switch. . .but it is looking deeper
like a computer malfunction or the computer is seeing an
error else where and just won't let the unit fire up. . .

The switch is a momentary type switch. . .ohms should be
infinite when not pressed and 0 when pressed. . .make sure
the contacts are not just shorting via the leads. . .

Electronics that can't be fixed easily are the stuff of
the electronics recycling programs. . . it truly stinks. . .

If the unit was mine, I would:

A) attempt to bypass all the ICs and just use it as an amp. . .

or

B) salvage the working power supply parts and make a chip amp
or an Aussie Amp. . .

I'm sorry for my bad news approach. . .but ICs and logic circuits
are generally not repairable and require board swapping. . .

I'll be the amp section is still good. . . .
 
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