Onkyo TX-SR308 Only picture No sound

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

Yes, i used the right settings on my DMM. But turns out that the DTS has alot of Vss pins which is connected to GND (refer to picture 1 below). That explains why i hear those beeps. Could be normal after all.

And yes both regulators were removed. Everything highlighted and circled in picture 2 was removed. Thats every IC and diode connected to 3.3V, unless i missed something. The resistors and capacitors cannot possibly cause the low ohm reading...can it? I know that reading across inductors normally cause beeping sound.

So what else could possibly be the cause? Im stumped!!

[keeney123]

Re: Onkyo TX-SR308 Only picture No sound

Yes, i used the right settings on my DMM. But turns out that the DTS has alot of Vss pins which is connected to GND (refer to picture 1 below). That explains why i hear those beeps. Could be normal after all.

And yes both regulators were removed. Everything highlighted and circled in picture 2 was removed. Thats every IC and diode connected to 3.3V, unless i missed something. The resistors and capacitors cannot possibly cause the low ohm reading...can it? I know that reading across inductors normally cause beeping sound.

So what else could possibly be the cause? Im stumped!!

So the low ohm reading does not beep if set on the low ohm scale. It only beeps on the diode setting scale. That would be the wrong setting. On the diode setting one can read diodes or transistors that are forward bias. If a chip has one of these components in them you could read that as a beep. Nothing may be wrong with the chip in this case. A low Ohm reading will only read ohms on the right setting. There will be no beeps no matter what. Yes a capacitor can short out.

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

So the low ohm reading does not beep if set on the low ohm scale. It only beeps on the diode setting scale. That would be the wrong setting. On the diode setting one can read diodes or transistors that are forward bias. If a chip has one of these components in them you could read that as a beep. Nothing may be wrong with the chip in this case. A low Ohm reading will only read ohms on the right setting. There will be no beeps no matter what. Yes a capacitor can short out.

I have tested it in diode mode to hear the beep. And tested it again in low ohm range to get the low ohm reading. Of course I know how to use a DMM. I have been repairing TV's for 3 years!!!

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

As mentioned in post #19...

I just tested the connection between 3.3V and GND in diode mode. Got a beep both ways. Measured the resistance, i got low ohm at around 4.6 ohms.

So you mean there's nothing wrong with that?

[madan1]

Re: Onkyo TX-SR308 Only picture No sound

apart from the beep, what was the resistance in ohms?

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

I cant tell if youre joking.

4.6 ohms

[keeney123]

Re: Onkyo TX-SR308 Only picture No sound

I cant tell if youre joking.

4.6 ohms

So yes there was some confusion as to how it was measured this is why questions get asked and not to give you a hard time. Yes, 4.6 Ohms is way to low. So do any of these ICs seem kind of hot to the touch when power is applied? Also if you have a very accurate meter like a Fluke you can set it to the lowest ohm setting and hold one lead stationary to one point and move the other around. You are looking for the lowest reading. Once you find that point then hold the probe there and move the other one around. This will get you with in three inches of the short.

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

All good mate, let's get back to the problem.

Just to recap, I have already removed nearly all the ICs and diodes connected to 3.3V, namely the ones highlighted and circled in the diagram below. Still reads 4.6 ohm between 3.3V and GND.

Havent turned it on to feel the temperature because the ICs and diodes are all still out of the circuit. I dont have a Fluke meter, just a mid-budget meter. Do u still think it will help? because 3 inches is quite a large distance, condsidering the components are tightly spaced on the HDMI board.

Also you said earlier that capacitors can short out. Is it possible the capacitors in the diagram (in blue) need to be replaced?

[madan1]

Re: Onkyo TX-SR308 Only picture No sound

I asked you about the readings, because for instance my low-budget multimeter has a very high diode/beep threshold, and lots of times it will beep without an actual shortage.

I do not see in your diagram the hdmi ports RN1401 removed.. have you checked them also?

[syaoran123]

Re: Onkyo TX-SR308 Only picture No sound

Or maybe you didn't read carefully when I said I got 4.6 ohm on post #19. OR in post #1 when I said I have 3 years TV repair experience and underestimated my knowledge. But I understand there's alot of info and it's quite easy to miss things...anyway so lets just move on from here.

I have good news and bad news.

Good news is I found the cause of the beeping. I decided to remove the DTS chip with my heat gun and beeping stopped. The DTS chip was faulty albeit no visible signs of damage.

The bad news is it's difficult to find a stockist for the chip, let alone another HDMI board. So im going to have to destroy the HDMI board, and possibly the whole AVR unit.

Im very grateful for your assistance guys, and I learned a thing or two about diagnosing AVRs.

[keeney123]

Re: Onkyo TX-SR308 Only picture No sound

Or maybe you didn't read carefully when I said I got 4.6 ohm on post #19. OR in post #1 when I said I have 3 years TV repair experience and underestimated my knowledge. But I understand there's alot of info and it's quite easy to miss things...anyway so lets just move on from here.

I have good news and bad news.

Good news is I found the cause of the beeping. I decided to remove the DTS chip with my heat gun and beeping stopped. The DTS chip was faulty albeit no visible signs of damage.

The bad news is it's difficult to find a stockist for the chip, let alone another HDMI board. So im going to have to destroy the HDMI board, and possibly the whole AVR unit.

Im very grateful for your assistance guys, and I learned a thing or two about diagnosing AVRs.

Good to hear you found the problem. So I do not have to go through all of the post can you give me the number on the chip so I can help you look?

[keeney123]

Re: Onkyo TX-SR308 Only picture No sound

I asked you about the readings, because for instance my low-budget multimeter has a very high diode/beep threshold, and lots of times it will beep without an actual shortage.

I do not see in your diagram the hdmi ports RN1401 removed.. have you checked them also?

So he was saying that on the ohm setting "not" the diode setting he was reading 4.6 ohms from 3.3 volt to ground.