why does my receiver keep shutting off?

My formerly trusty Sherwood receiver, which I've had for over a decade, keeps randomly shutting itself off. Sometimes immediately, sometimes after a few minutes, sometimes it'll play fine for an hour or more and not shut off at all. It's a secondary system I don't use much so I'm wondering if it's worth getting repaired or if there's anything I can do (short of soldering something) to fix it myself?

 

Is it connected to the network? Does it automatically update firmware over the internet? If so, you may encountering the firmware update process, whereby the system goes into standby while the firmware downloads and installs on the receiver.

 

Thanks for the reply but no, no network involved. Just a receiver connected to two speakers, plus a CD player. I mostly just listen to the radio.

 

I'm not familiar with your receiver, but perhaps it's a built in over heating feature?
Make sure your receiver has adequate airflow.

 

This is what occurred to me. Most receivers of the Sherwood era had thermal protection that would shutdown the receiver when it exceeded a certain temperature. In my experience, the protection becomes much easier to trip after it has been tripped for the first time. Once it trips several times, it starts getting fairly random.

 

this was a serious reply?

 

Ditto RE: overheating protection.

The sensor could also be going bad. I had a Sony receiver that was faulted in this manner and would constantly go into protect mode. Very annoying and not an easy fix for the uninitiated (myself included).

 

Upon re-reading it and remembering my experience again, what I originally posted is not not completely accurate. Actually, if you interrupt a firmware update, it may attempt to download it over and over again every time you turn your receiver back on. Symptomatically, it will go into standby while it updates, although it will appear like randomly shutting down. I went through this with my Marantz.

The heat explanation sounds like a good possibility.

 

i didn't know receivers did firmware updates. i'm really out of the loop i guess. i take it the receiver is connected to a computer?

i know my cd "turntable" has firmware updates that must be downloaded, burned and then "played" in the player.

 

10 year old receivers do not do firmware updates. I have a Yamaha RX-V2300 that does this very same thing. I read about the issue, it was some sort of faulty overheating sensor or faulty impedance overload sensor shutdown problem. I just replaced the receiver. Whether the receiver is actually overheating or not probably doesn't matter, repairing something like that is not likely feasible.

 

Thanks for all the replies. I was suspecting heat, it does seem to occur more when the room is quite warm. Which it is whenever the sun has been shining all day. Time to buy a little fan, I guess and start saving up for a new receiver.

 

One good trick is to buy a small 12-volt mini fan, and then run it from a 6-volt power supply so that it turns at half-speed. It makes much, much less noise that way.

In the old satellite days, I had a Chaparral satellite receiver that ran very hot, and used a small fan this way just to avoid letting it get cooked. You couldn't even hear the fan if you were at least 5 feet away from it.

 

Actually, receivers and digital sources are becoming increasingly network capable appliances. They plug into computer routers or access points with standard CAT5 cable. This gives you the ability to be notified of firmware updates, and download and install firmware updates via your receiver/sources on screen programming. In addition, you can access a browser-based version of the setup and configuration settings, as well as some level of browser based remote controlling. Another cool way to realize the benefits of networking audio/video is by using iPhone or iPad apps to remote control your electronics. All this combined with music and video servers as sources and streaming which has already been developing for several years now.

The interfaces to all this stuff is often somewhat crude and slapped together looking, but the potential of all of this, as it becomes more refined, is pretty cool.

My apologies for straying from the OP topic, I'll stop right here.

 

Thanks for the tip. I have several desktop carcasses at my disposal, I was thinking of taking a fan out of one of them. I'm sure I must have an old variable voltage wall wart that I could use to step it down.

 

i was just confused because in the OP, he said he had a decade old sherwood.

 

Your symptom sounds very much like speaker wire +/- touching somewhere. Do a very careful check of both sets of wire to make sure there is no chance of the +/- leads touching near the speaker, near the receiver, or any damage to the jacket.

 

I would buy new speaker cables and re wire your set up then make sure your outlet is ok then check your plug,simple first then go from there.

 

I had that very issue with a Kenwood home theater receiver. Definitely check the speaker connections.

Jeff

 

This was exactly what I thought -- this happened to me once and resetting the speaker/receiver connections solved the problem.

 

If the fan doesn't work, it could be DC offset tripping the overload protection circuit

 

It might be something to do with the power switch.

Is it a model which came with a remote? If so the actual power switch will be servo controlled and the button on the front will be a momentary switch which sends a signal to the servo to turn the unit on. Even if it didn't come with a remote it might be setup like that.

I've had the trouble you're describing with a seldom used Sherwood receiver before. It was a basic stereo unit.

What fixed it was pressing the power switch a bunch of times while the power was off. I might have sprayed a bit of contact cleaner in there as well, but I don't recall.

 

If the desktop fan works, you might want to consider replacing it with a quiet case fan: http://www.endpcnoise.com/cgi-bin/e/std/category=Quiet_Case_Fans.html

Other causes of your problem could be from a part in the protection circuit going bad or as another poster suggested, DC offset. A part or parts going bad in the differential stage would cause random high DC offset.

 

Thanks for the suggestions, everyone. I will check the wiring tonight and look into the other things people have mentioned. Last night was unseasonably cool and it played for an hour without any problems.

 

Does your receiver have wireless remote control? If so, especially the early ones that used RF, outside frequency sources could be causing it.

Most receivers have a built-in circuit breaker. I had a similar problem with my 2-year old Sony receiver. It ended up being a shorted wire to my subwoofer. I sealed off and added a 120V fan to the cabinet that I have all my home theater components in before I discovered the real problem. The fan was an excellent idea anyway.

These fans can be purchased cheaply at Radio Shack or any electronics store. They usually come without a plug. I went over to Home Depot and bought an extension cord for the plug at a fraction of the price RS wanted.

 

Yep, and you could open her up, and spray some compressed air on some of the resistors in the amp and preamp sections to cool them off and see where the problem is, if it comes back on, your problem lies there.