there is no sound output on the speakers anymore

Question

Amplifier

Repair and disassembly information for amplifiers in home audio systems.

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Felix M @schniefelix

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게시일: 2021년 11월 5일

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there is no sound output on the speakers anymore

I dont understand much of the internals of my technical devices, unfortunately. Its getting power and I can turn it on, LED's are shining from inside and from the power button. Also you can connect other devices t the AC-Power Outlet. But there is no sound output on the speakers anymore. I tried every input channel, different cables and every output speaker channel. All dead output.

And diffrent speakers of course

Im affraid I damaged it when I, in my stupidity, coneccted a battery powered fary lights to the music output (speakers) adapter/ports. I know, I shouldnt have done that. But im not sure its realy the reasen for it to be dead and I never would understand whats damaged exactely.

Thanks for your interest! Havent expected that :)

PS: I also checked the boards inside for any burned stuff. But with my untrained eyes I coulnd find any obvious damaged components

Update (11/06/2021) ===

ok I got the multimeter now and watched some youtube videos to get an expert.

I would set it like on the photo to measure the 2.2V:

But then… Where do I have to touch the black and red stick of the multimeter? One of them to the 7th pin of CI 401 (photo), but which one? And the second to…?

And I’ll do all this while the amplifire is pluged in and powered on right? Little afraid of that :)

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@schniefelix let's see what we can find out. I wonder if it is the amp stage that got "shocked". Basically everything works except there is not sound.?Just to make sure, have you check with a headset yet?

oldturkey03 의 2021년 11월 5일

Ohhh! Now that you say it and I listen REALY carfully: There is some output for the headphone. But its VERY weak/silent.

From the speakers i still hear nothing than silence

Felix M 의 2021년 11월 5일

@schniefelix sounds like the amp stage is blown. Can you post some good pictures of your circuit boards (both sides) with your QUESTION? That way we can see what you see and might identify the components/circuitry that you need to focus on. You will need at least a multimeter.....기존 질문에 이미지 추가하기Did you hook it up to where the speakers connect to? If so there is a board that has two relays on it and those can act like fuses......

oldturkey03 의 2021년 11월 5일

I try to organize the multimeter as soon as possible.

I hocked up the headphones on the front pannel instead of the back.

Relays are those two blue boxes on the Audio-Out Board right? I was wondering if those might functioned as a fuse and saved my ass, kinda. But when I was trying to understand their funktionality I thought I coulndt test them with the multimeter becuase they worked like a switch (which is turned off). But I might got wrong with that understanding?

Felix M 의 2021년 11월 5일

@schniefelix yes, those are the relays. Did you try and connect the battery powered lights to that board (picture number 6)?

oldturkey03 의 2021년 11월 5일

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@schniefelix let's see what we can find out. I wonder if it is the amp stage that got "shocked". Basically everything works except there is not sound.?Just to make sure, have you check with a headset yet? — oldturkey03
Ohhh! Now that you say it and I listen REALY carfully: There is some output for the headphone. But its VERY weak/silent.

From the speakers i still hear nothing than silence — Felix M
@schniefelix sounds like the amp stage is blown. Can you post some good pictures of your circuit boards (both sides) with your QUESTION? That way we can see what you see and might identify the components/circuitry that you need to focus on. You will need at least a multimeter.....기존 질문에 이미지 추가하기Did you hook it up to where the speakers connect to? If so there is a board that has two relays on it and those can act like fuses...... — oldturkey03
I try to organize the multimeter as soon as possible.

I hocked up the headphones on the front pannel instead of the back.

Relays are those two blue boxes on the Audio-Out Board right? I was wondering if those might functioned as a fuse and saved my ass, kinda. But when I was trying to understand their funktionality I thought I coulndt test them with the multimeter becuase they worked like a switch (which is turned off). But I might got wrong with that understanding? — Felix M
@schniefelix yes, those are the relays. Did you try and connect the battery powered lights to that board (picture number 6)? — oldturkey03

oldturkey03 @oldturkey03 평판: 782.2k 1.1k 893 2.3k · Answer 1 · 2021-11-05T19:46:55-07:00

oldturkey03 @oldturkey03

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@schniefelix it did get a little later than expected. Anyhow, for now and this is not yet an answer, here is the partial service manual for this model which includes all the schematics. We can only be on the same page if we got the same book :-) The board where the speaker connections and the relays are is the Sp TM board and we’ll have to work our way up from there through CN501 and CN502 Sony TA FE910R SM

Looks like one of the relays controls power to the ,main board and the other provides speaker protection. So when you turn your Amp on you should actually here a “click click” when both relays get energized. Since you have lights etc. I would expect at least one click. Let us know what you hear or “feel on those relays.

IC401 on the main board is a UPC1237 Amplifier Protection IC which we can check the voltages on according to the schematic. Pin 7 on this should have 2.2V to close the relay for the speaker circuit.

If you do not yet have a multimeter and have not tested live circuits you want to let us know so we can provide a bit more guidance on that. Potential touching a component/circuit while it is “hot” could be a shocking experience :-) So no rush and we shall get there eventually.

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I hear the click click. even though Im not 100% sure both of the click's are coming from the relays. It sounds like there is a louder click coming from the other side/ right side (opposite to the relays on the left). When I turn it Off it sounds the same. There is definetly one click from one of the relays. The louder one is hard to locate. Plus there is the clicking of the Power Button which is nearly simultaneously with the electronic cklicks.

I cant feel anything from the relays, touching the top.

Beside that, I found all components you listed on the scheme and on the boards.

I didnt use a multimeter yet.

Felix M 의 2021년 11월 6일

@schniefelix yes, the meter is set correctly. The amp will have to be on which can make it a bit tricky to check, since you do not want to shorten out any pins etc. Place the black probe on ground (one of the screws that holds the board to the chassis will most likely carry ground) and the red probe on pin . It should show you 2.2V.

oldturkey03 의 2021년 11월 8일

on this settings it shows 0,02. Thats one zero too much right?

PS: I double checked it now: When the Amp is pluged in but powered "OFF" there is 2.1to2.2 V. Just when I turn the Amp "ON" its just 0,02V.

Felix M 의 2021년 11월 9일

@schniefelix you will have to check the components in the same circuitry. Let‘s see if the IC is the issue or a components that has failed around the protection IC. Csn you check the other legs on the IC as well? Just compare the voltages with the one given in the schematic

oldturkey03 의 2021년 11월 9일

Pins: scheme value / measured value

1: 0 / 0

2: 0 / 0,76

3: 0 / 0,79

4: 4,2 / 4,5

5: - / -

6: 0,8 / 46 (fourtysix)

7: 2,2 / 0,2

8: 3,2 / 3,3

Felix M 의 2021년 11월 9일

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