I have a Sony STR-DE945. The center channel usually cuts out after the unit has been on for about 10 mins, accompanied by the click of the center channel relay (RY601). I've seen a few posts about this issue, but it seems that most people see "Protector" come up on the display when this happens. I do NOT have this problem. Also, if I give the unit a slap, the center channel usually comes back (not always). I don't think I have any issues with the power amps or boosters (Q604-Q607) otherwise I assume I'd be seeing "Protector" on the display. I haven't been able to find any cold solder joints - that's not to say there aren't any really tiny ones that I've missed. I have the STR-945 service manual, but it doesn't include voltage levels for various components.
I was wondering if anyone knew what the voltage levels should be at the relay driver input and output (Q645) when the relay is engaged (center channel on) and disengaged (center channel off), and on the relay itself, so I can determine if the 945 is intentionally shutting down the center channel, or if I have a bad relay or relay driver. I opened up the box and probed around while playing a DVD with the center channel working, but unfortunately (or fortunately depending on how you look at it) I didn't see the same switching behavior (possibly due to better airflow since it wasn't in my entertainment center), though I did replace the case and covered the vents to try to let the unit heat up (for about an hour). In any case, the center channel never cut out. Either the unit hadn't heated up enough to cause the issue or I "fixed" a cold solder joint through probing and/or wiggling components.
Any info on those voltages would be helpful in case the issue crops up again.
I have had the same Issue. The center channel would give out after the receiver was well heated.
One method that seemed to help, is to make sure the whole thing cools, (inside).!!! Opening the Ent.. center door for about 15 min, or aim a fan inside, at it. Once the unit is cooled all the way down. Then I Turn the (A, off, A&B) speaker selector switch to the OFF position, Next, turn the receiver on, after about five seconds, Turn the selector Back to A&B. This does the trick for my system, Dont forget to use AFD mode for the suround.
I believe that after some of the relays or internal switches get so old, they become to heat sensetive and the AB switch resets them after being aloud to cool off so the triping stopps. Im going to take mine out of the center and see if that will prevent the over heating.
Good luck every one!!!!! I have had the same Issue. The center channel would give out after the receiver was well heated.
One method that seemed to help, is to make sure the whole thing cools, (inside).!!! Opening the Ent.. center door for about 15 min, or aim a fan inside, at it. Once the unit is cooled all the way down. Then I Turn the (A, off, A&B) speaker selector switch to the OFF position, Next, turn the receiver on, after about five seconds, Turn the selector Back to A&B. This does the trick for my system, Dont forget to use AFD mode for the suround.
I believe that after some of the relays or internal switches get so old, they become to heat sensetive and the AB switch resets them after being aloud to cool off so the triping stopps. Im going to take mine out of the center and see if that will prevent the over heating.
Good luck every one!!!!!
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Stereo Tech: Sounds like you definitly have a broken solder connection on the main PC board. A bad solder connection is tricky to find somtimes if one is not familiar with exactly what it looks like (kinda like mt st helens with a ring around the top) if you attempt this yourself DO NOT MAKE A SOLDER BRIDGE you will open pandoras box. Good luck
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Sometimes these units have the ability to switch the speaker off and on. Look up the speaker settings in the manual.
As each channel in the unit will be separately driven the power amp for the center channel could have failed, but I think it's unlikely unless you have had problems with the sound on it before, or connected it wrongly causing a fault.
Sony STR-K840P Sound center speaker - Questions - Fixya
www.fixya.com > ... > Sony > Sony STR-K840P
... sound from center channel during viewing, or during speaker level test- all other speakers emit tone, but center is dead. I have optical digital cable and hdmi ...
Sony STR-K840P Sound center channel - Questions - Fixya
www.fixya.com > ... > Sony > Sony STR-K840P
... sound from center channel during viewing, or during speaker level test- all other speakers emit tone, but center is dead. I have optical digital cable and hdmi ...
First of all check that it has not got switched off somehow. After that, what I would do is trace the wires back (inside the unit) from the center speaker connector. This will take you back to the output semi-conductors for that channel. I would suspect these first, you might even see damage! You should anyway be able to look the numbers up on the net. If they are cheap I would replace them anyway. If that doesn't work I suggest you hunt down the service manual, it might have suggestions in it.
Try connecting it to the left or right output from the amp to make sure the speaker actually works. It might be the receiver that's the problem. Also, you must be in one of the surround sound modes on the receiver and not the "phantom" mode as it does not give output to the center channel.
Hi,
Happened across this forum looking for some remote info. Had a similar problem with my 945...main speaker outputs started to click off & on, no rhyme or reason. Found that the solder joints on the speaker output relays were cold (poor soldering). Actually happend twice, two different relays. Took me a while to find it, reflowed the solder, that solved the problem, over two years ago now. Are you able to dig into the receiver? Do you have a (good) soldering iron and some solder? If not take it to elec. shop and tell them to look for cold joints on the relays.
I have had the same Issue. The center channel would give out after the receiver was well heated.
One method that seemed to help, is to make sure the whole thing cools, (inside).!!! Opening the Ent.. center door for about 15 min, or aim a fan inside, at it. Once the unit is cooled all the way down. Then I Turn the (A, off, A&B) speaker selector switch to the OFF position, Next, turn the receiver on, after about five seconds, Turn the selector Back to A&B. This does the trick for my system, Dont forget to use AFD mode for the suround.
I believe that after some of the relays or internal switches get so old, they become to heat sensetive and the AB switch resets them after being aloud to cool off so the triping stopps. Im going to take mine out of the center and see if that will prevent the over heating.
Good luck every one!!!!!
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