Any A/V experts in here?

[Ceezer]

I have a receiver in my garage that, when turned on, will play for 2-4 seconds but then cuts out (not off). If I turn the receiver off and back on, it does the same. If I just change the input selection from one to another (say, FM to CD) it doesn't do anything, I have to turn it completely off (but it doesn't matter which input I have selected, I still get 2-4 seconds of play before cutting out).
When it cuts out I can turn the volume up and hear power being delivered to the speakers, just no signal. I bought all this stuff new in '98, so I know the history of it and that it has been treated well, and it was working fine up until this just started happening.

Receiver is a Sony STR-DE325, powering a pair of DCM KX10 Series II floorstanding speakers, with RCA inputs from my TV and Phillips CDR 765, plus an auxiliary input cable that I hook into an iPod.

 

[nehog]

A few seconds of 'sound' may be normal, as the power in the power supply filter capacitors bleeds down to zero.

 

[Jawn]

A few seconds of 'sound' may be normal, as the power in the power supply filter capacitors bleeds down to zero.

Might be normal for turning it OFF, but not for turning it ON.

 

[Ceezer]

Could it be that, maybe, the speaker wires are making contact somewhere and are shorting out? Would that produce a similar result? I haven't moved the speakers or receiver in some time, but I suppose that doesn't completely rule out the possibility...

 

[Matt M PA]

I too would suggest checking the speaker wiring, and make none are crossed, touching, etc.

 

[SpeedCoach]

x3 on the speaker wiring. make sure the wiring isn't stripped so far down so that wires on either end (receiver or speakers) are making contact.

 

[PrecisionTools]

Like you said...if you turn the volume up you can hear the speakers work so I'd say they are OK. If there is a speaker issue usually you will hear a click as the amplifier's safety circuitry will isolate the amplifier via the speaker relays, and the unit will shut down or you will get some sort of error message show up on the display.

My guess is that the audio amplifier IC in the unit has either got dry joints on the pins or it has internally died. Pretty common for these to fail over a period of time. I'd say only an Audio repair tech can help you out here.

 

[slopecarver]

Sounds like you might have let some smoke out. Crack it open and look for anything amiss, look closely at all of the solder joints. People think that because there are no moving parts nothing can break with these but thermally the do expand and contract causing joints to fail. It almost sound like a resistor might have a bad connection and make contact for 2-4 seconds then as it heats up it flexes and loses contact.

 

[nehog]

Might be normal for turning it OFF, but not for turning it ON.

****, misread the original post...

This is a Sony unit, they have had MASSIVE problems with the conversion to ROHS that removed the lead from solder. I have two high-end Sony systems, and both have similar problems. (I've decided to never again buy a Sony system because these were so bad...)

Suggestion: try hitting as many solder connections on the boards as you can with a hot iron (perhaps adding solder as necessary). That may resolve it.

 

[PrecisionTools]

This is a Sony unit, they have had MASSIVE problems with the conversion to ROHS that removed the lead from solder.

Bought in '98...would this pre-date ROHS in the US?

 

[ket-tek]

The amp sounds like it is going into protect mode.

Before going straight to internals, always check the simplest things first. Obviously if the speaker wires touching each other or the chassis can cause an issue.

Second issue I've seen often is the impedance being wrong. Most home amps and speakers are 8 ohm, and so usually no issues.

Alot of receivers have a switch on the rear to select between 4 and 8 ohm (sometimes it's a menu option).

And some home/studio speakers are 4 or 6 ohm that I have seen.

So just make 100% your properly pairing the combo.

 

[Ceezer]

Thanks for the suggestions, folks.

- I checked the speaker wires and they're fine. I have them connected via very durable wire (for car audio competition) and see no fraying, nicks, etc and there is no exposed wire at either end to make contact. The receiver, stand it sits on, and speakers have been in their current position for more than a year, so there has been no movement that might have caused this disruption.

- I don't see a switch on the back to select between 4 or 8 ohm, nor could I find any such option when going through all of the button menus.

- I forgot to mention in my initial post, there are no error messages on the display.

- I haven't taken the cover off to look at the board, so it's quite possible a soldered connection could have just come loose, but I smell no frying

- Something else (slightly odd) I determined while messing around and trying to find the impedance options: If I have the source set to FM tuner and press the button to change from mono/stereo, the sound comes back for just a second...