My receiver powers up but nothing happens

M

mstrane21

Well-Known Member

• Sep 1, 2014

• #1

I picked up an old Onkyo TX-37 the other day for cheap. I didn't need it but you know how that goes, and it's heavy as heck for its size. There weren't any speakers or headphones in the store to test output, but it powered up and the lights worked, all except the lights next to the Tuner button. The display showed the proper station number as it should. I say that because when I got it home, I plugged it in, and it powers up and comes out of protection, but the display reads as pictured below, no matter which input selection I choose. None of the other display lights work anymore. There's a faint fuzzy noise coming from both the speakers and headphone outputs.*

What's the likely culprit here? I know it's a low end receiver and I only have 10 bucks in it, but I want to try to fix it if it's something simple. Any ideas would be appreciated. Thank you

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markdi

Natural born thread killer

• Sep 1, 2014

• #2

Check tape monitor switch position

 

petehall347

the brandy coffee man

• Sep 2, 2014

• #3

have you got an antenna connected ?

 

M

mstrane21

Well-Known Member

• Sep 2, 2014

• #4

It did the same thing when I had an antenna connected. It just kept the same scrambled display no matter which input position I chose.

I have jogged the tape monitor switch and it didn't change anything.

 

petehall347

the brandy coffee man

• Sep 2, 2014

• #5

try pressing the buttons a few times ..one may have got pressed in and stuck when you moved it .
also remove any fuses any put them back in ..that's just in case one has a dirty connection . maybe not that though .

 

M

mstrane21

Well-Known Member

• Sep 2, 2014

• #6

Unfortunately I have tried all that too! I guess I could install new fuses but they don't look blown.

 

Binkman

Lunatic Member

• Sep 2, 2014

• #7

service manual; fair

http://www.hifiengine.com/manual_library/onkyo/tx-37.shtml

 

sregor

AK Subscriber

Subscriber

• Sep 2, 2014

• #8

Could be CPU related. One possible problem is the crystal for the CPU has gone bad. Look for about a 1/2 inch by 1/2 inch by 3/16 inch can with something like 7.2 mHZ or 4.5 mHZ on it. SHould be in the manual. If they have pre/main connectors, the amplifier section can be tested by running a signal into the main input. Keep the signal low at first.....

 

M

mstrane21

Well-Known Member

• Sep 2, 2014

• #9

sregor said:

Could be CPU related. One possible problem is the crystal for the CPU has gone bad. Look for about a 1/2 inch by 1/2 inch by 3/16 inch can with something like 7.2 mHZ or 4.5 mHZ on it. SHould be in the manual. If they have pre/main connectors, the amplifier section can be tested by running a signal into the main input. Keep the signal low at first.....

Click to expand...

There was white goo coming out of this fella (please see picture). Is that normal?

 

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shadow_419

Active Member

• Sep 2, 2014

• #10

Thermal paste, and completely normal. Could probably use a refresh of paste at some point, but probably not the most pressing issue.

 

petehall347

the brandy coffee man

• Sep 2, 2014

• #11

you could try a bit of gentle warming with a hair drier and see if it comes back to life .

 

BOUXY

AK Subscriber

Subscriber

• Sep 2, 2014

• #12

SHOOT IT and be done with it!

 

mhardy6647

Lunatic Member

• Sep 2, 2014

• #13

Make sure you aren't playing a performance of John Cage's 4'33" by mistake...

 

sregor

AK Subscriber

Subscriber

• Sep 2, 2014

• #14

mhardy6647 said:

Make sure you aren't playing a performance of John Cage's 4'33" by mistake...

Click to expand...

Or Nixon"s white house tape....

 

mhardy6647

Lunatic Member

• Sep 2, 2014

• #15

Marcel Marceau's Greatest Hits

we're not helpin' much, though, are we? :-(

sorry -- I'll stop now...

 

loopstick

AK Subscriber

Subscriber

• Sep 2, 2014

• #16

sregor said:

Could be CPU related. One possible problem is the crystal for the CPU has gone bad. Look for about a 1/2 inch by 1/2 inch by 3/16 inch can with something like 7.2 mHZ or 4.5 mHZ on it. SHould be in the manual. If they have pre/main connectors, the amplifier section can be tested by running a signal into the main input. Keep the signal low at first.....

Click to expand...

It does look as though the patient has a temporary brain problem. It appeared functional at the store. If you plugged it in at the store after it had been unpowered for a long time the uP may have completed a full power-on reset cycle. When you got it home some lingering charges somewhere may have prevented this from happening. If there are any AA batteries on the back I'd take them out. At any rate you have the option of just letting the thing sit for a few days and trying again. Binkman's manual may be worth a look. Maybe you can force a reset. Maybe Vcc is soft. Dunno.

 

Tom B

AK Subscriber

Subscriber

• Sep 2, 2014

• #17

I would also check the boards and look for a crack, or loose overheated connections by the large resistors and regulator transistors. Check and make sure the display is not broken, and that the display board is not cracked.

 

M

mstrane21

Well-Known Member

• Sep 3, 2014

• #18

I will check it out again tonight. I didn't notice any loose connections or cracks in any of the boards.

I emailed Onkyo hoping to get instructions on how to do a factory reset since there was nothing in the service manual about that (thank you to the person that posted that), but not holding my breath for a useful reply.

I almost think if I just let the thing sit for a few weeks I will just plug it in and it will just magically work. It does seem like a computer issue to me...like it's just stuck in a coma. I also think a reset would work if I could figure out the procedure. Thanks for the help all, even those who made light of the apparent demise of my MOTL, 25-year old, $10, BPC receiver.

 

Binkman

Lunatic Member

• Sep 3, 2014

• #19

Greetings;
There is no factory reset. I did post the service manual.

I have a tx-36 broken, similar condition also have the tx-82 (just bought a second) Very similar except the STK on your unit. The service manual has the stk diagram that you can check for opens. You would have to unsolder the stk from the main board, Not necessary to remove but might be easier to check out of box. If the stk is good it might be worth digging into the rest of it and recapping etc. They do sound quite good but it's tough to get stks from a trusted supplier.

 

Last edited: Sep 3, 2014

loopstick

AK Subscriber

Subscriber

• Sep 3, 2014

• #20

I didn't think there would be an official reset button. That would be an admission of failure. But I thought it would be worth looking at the chips. The main control chip has an inhibit function.

Onkyo doesn't seem to be using it, there are no switched inputs to pin 40. However pin 40 goes high with an RC time constant, kinda like power-up resets sometimes do.

Is this the problem? Heck if I know. The app note says the drivers go off, but another chip drives the numerical display. Anyhoo just wanted to draw attention to some under-the-hood stuff to consider. There is such a thing as an ambiguous reset state. Maybe there's such a thing as an ambiguous "inhibit" state. Ahhh, we're havin' fun that's all that counts. :thmbsp:

________________

 

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