Need some input - unusual receiver overheating issue

amplifiers, receivers and loudspeakers
Adamo0926
senior member
senior member
United States of America
Posts: 429
Joined: 26 Feb 2011 03:22
Location: Connecticut

Need some input - unusual receiver overheating issue

Post by Adamo0926 » 07 Jul 2019 03:14

Where to begin....I guess at the beginning. My best friend and I both have the same receiver, Yamaha CR-2020s. We both had them completely refurbished. Mine has been working flawlessly and sounding sweet since. His on the other hand had something just happen that must be pretty bizarre because I can't find anything about this situation anywhere online. So I thought I would turn to you guys.

Apparently his daughter was listening to his set up. But after and turning off the turntable she forgot to power down the receiver. He told me that it could have been on for a week. Which I didn't think should be an issue since I have read online that some people think it's best just to leave your gear powered up. Anyway, this morning his wife walks out of the bedroom and tells him she hears a noise coming from downstairs. Now mind you, the bedroom is on the top floor of the house and his system is in the finished basement, 2 floors down from the bedroom.

He goes downstairs and opens the door to the basement and hears what he described as a very very loud humming. It was so loud he thought there might be a problem with the central AC. But when he goes downstairs the sound is coming from the CR-2020. He also said the top of the receiver was literally scorching hot, so much so that you couldn't really touch it. He said it would almost be like putting your hand on top of a grill.

Obviously there is some kind of major issue going on here. He considers himself lucky that the thing didn't catch fire since it got so hot.

Now obviously I don't think a receiver should do something like this just by the power being left on. Absolutely nothing playing.

So does anyone have any idea what would cause something like this ? We both spent quite a sum of money to have these things completely reconditioned. And now, even though mine is working flawlessly at the moment, I'm starting to worry a bit about my CR-2020.

Any advice or theories are welcomed....thanks.

Tinkaroo
vinyl addict
vinyl addict
Canada
Posts: 7351
Joined: 04 Feb 2011 20:00
Location: Pixie Hollow by The Bay

Re: Need some input - unusual receiver overheating issue

Post by Tinkaroo » 07 Jul 2019 12:21

You don't say if the receiver is working OK or not afterwards?

A couple of thoughts:
- Sometimes a phono input can hum if left on with the turntable off.

- What percentage of volume was the receiver left on?
- Are the vent openings open and unobstructed?

-Depending on the bias settings of the receiver it is possible to run hotter than normal.If the components used in the rebuild are higher than factory and it's working OK now then nothing to worry about other than the daughter perhaps. #-o

vanakaru
senior member
senior member
Posts: 477
Joined: 24 Mar 2015 09:05

Re: Need some input - unusual receiver overheating issue

Post by vanakaru » 07 Jul 2019 12:39

It may be that some component died suddenly. I have heard awful hum if one of the power caps got disconnected and it caused the end transistors heat up pretty fast.
I would try to turn it on. Just make sure you have Phono active as Tinkaroo sais. If the hum comes back you need to take it to the repair again. If not you may be just fine.

circularvibes
long player
long player
Posts: 1234
Joined: 24 Sep 2010 02:09
Location: Ottawa, Ontario, Canada

Re: Need some input - unusual receiver overheating issue

Post by circularvibes » 07 Jul 2019 13:49

My Sansui and my JVC receivers had this issue and it was the filter capacitors each time. Get it fixed before using it again, I didn't and lost output transistors in a channel.

lenjack
long player
long player
Posts: 1615
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Need some input - unusual receiver overheating issue

Post by lenjack » 07 Jul 2019 14:53

A below par part might have been used in the refurbishing. Better look into yours as well, if you had the same servicing. You may be headed for the same failure.

Adamo0926
senior member
senior member
United States of America
Posts: 429
Joined: 26 Feb 2011 03:22
Location: Connecticut

Re: Need some input - unusual receiver overheating issue

Post by Adamo0926 » 07 Jul 2019 16:17

Thanks for all that input. I talked with a different tech who told me that leaving a piece of equipment on for that length of time is very bad. Before I even told him about the overheating he said that would cause the transformer to overheat because it would be on constantly with no load. (I'm paraphrasing here, so if this is not exactly technically accurate it's because I am interpreting what he said). Bottom line, when I told him it was left on, he immediately said that would cause very bad overheating before I had a chance to tell him the thing did overheat. So he must know what he's talking about because he was spot on about the severe overheating.

I read that people think it's better to leave equipment powered up all the time. But common sense tells me that can't be a good thing. For instance, my Marantz CD6006 deck always lets power run to it when it's plugged in. But it's in a state called stand by mode. Which means it must be letting the current in but not like it would be totally powered on and just sitting there. And the manual says that if you will be away for a length of time to unplug the unit so it won't sit there in stand by mode for a long length of time.

To answer some of the questions from above, the vent openings are completely unobstructed and the volume knob was at 1 or just above.

He told me he did test it again with the turntable and only one channel was working. He did not test with the CD player yet. But when I was there before any of this happened I thought there was a loose connection on the turntable that was intermittent and was causing one channel to drop out. So we won't know about the 2nd channel until he tests it with another output.

I'm guessing that if the thing got that hot there might be some transistors that got fried, and the tech told me that hopefully the transformer didn't get damaged because, well, that would be all she wrote...

Another day in the life of vintage audio obsession....

lenjack
long player
long player
Posts: 1615
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Need some input - unusual receiver overheating issue

Post by lenjack » 07 Jul 2019 16:24

I totally disagree that leaving it on for a long length of time would cause this. That tech is completely wrong. You mentioned earlier, that some folks leave their equipment on, 24/7, without problems. That is true. In the past, I, and some of my friends, have done so, for extended periods of time, with no ill effects. You need a different tech, who knows what he is talking about.

Tinkaroo
vinyl addict
vinyl addict
Canada
Posts: 7351
Joined: 04 Feb 2011 20:00
Location: Pixie Hollow by The Bay

Re: Need some input - unusual receiver overheating issue

Post by Tinkaroo » 07 Jul 2019 16:38

He should check it with another source such as FM or CD. It may be a bad connection on the turntable as you mention.

The receiver should be able to stay on indefinitely with no ill effects. It probably reaches an equilibrium temperature within a couple of hours and these things are tested to ensure there are no problems due to running continuously.

Adamo0926
senior member
senior member
United States of America
Posts: 429
Joined: 26 Feb 2011 03:22
Location: Connecticut

Re: Need some input - unusual receiver overheating issue

Post by Adamo0926 » 07 Jul 2019 17:34

lenjack wrote:
07 Jul 2019 16:24
I totally disagree that leaving it on for a long length of time would cause this. That tech is completely wrong. You mentioned earlier, that some folks leave their equipment on, 24/7, without problems. That is true. In the past, I, and some of my friends, have done so, for extended periods of time, with no ill effects. You need a different tech, who knows what he is talking about.
Here are my thoughts on this. I think a new piece of equipment under perfect conditions, I agree with you that leaving it on should not present any issues. However, we are talking about a piece of equipment that is over 40 years old. I can't imagine that leaving it powered on 24/7 could be a good thing. So as one previous poster said, perhaps as it was left on for all that time that a component died suddenly and caused the severe overheating.

No matter what the cause, obviously something is awry that it would super heat to that degree.

He has had his receiver with 2 different techs so far and the thing is still experiencing issues. So this tech will be number 3. It makes me begin to wonder if any of these people actually know what they are doing....

Tinkaroo
vinyl addict
vinyl addict
Canada
Posts: 7351
Joined: 04 Feb 2011 20:00
Location: Pixie Hollow by The Bay

Re: Need some input - unusual receiver overheating issue

Post by Tinkaroo » 07 Jul 2019 17:58

I've read a few comments that the CR-2020 tends to run hot:

One such example here:
https://audiokarma.org/forums/index.php ... 337/page-2

Adamo0926
senior member
senior member
United States of America
Posts: 429
Joined: 26 Feb 2011 03:22
Location: Connecticut

Re: Need some input - unusual receiver overheating issue

Post by Adamo0926 » 07 Jul 2019 18:26

Tinkaroo wrote:
07 Jul 2019 17:58
I've read a few comments that the CR-2020 tends to run hot:

One such example here:
https://audiokarma.org/forums/index.php ... 337/page-2
I remember reading things of that nature also, Tink. My receiver is far enough away from where I listen that I could get a nice quiet small fan for it.....which I might do after this incident with my friend's cr2020

vanakaru
senior member
senior member
Posts: 477
Joined: 24 Mar 2015 09:05

Re: Need some input - unusual receiver overheating issue

Post by vanakaru » 07 Jul 2019 19:14

You tried it and there was no hum - just one channel dead. Simple test would be to touch RCA plugs disconnected from the source. The amp should make some noise on both channels according to the L&R plugs you touch. If it does not pass this test then one channel is kaput.
Often refurbishing means that the caps get replaced. It means unsoldering these and if done with poor skills or poor equipment the amp may be in worse state than before. Also original caps are usually at very high audio quality and same Q range replacements are expensive. Thus temptation to use cheaper ones.

lenjack
long player
long player
Posts: 1615
Joined: 23 Jun 2017 02:11
Location: Liverpool,PA

Re: Need some input - unusual receiver overheating issue

Post by lenjack » 07 Jul 2019 19:42

I'm guessing that the refurbishing was poorly done, with low grade replacement parts. Off the shelf replacement parts, easily and readily available to a tech, are usually not of the same quality as the original oem parts. They tend to under perform, and have poor longevity. They can fail by causing the unit to completely shut down, or doing what your friend's unit did. Many people hold themselves out as techs, but very few are truly well qualified. A properly refurbished unit will have no problem with being left on continuously.

AsOriginallyRecorded
senior member
senior member
Canada
Posts: 780
Joined: 26 Jun 2018 06:05

Re: Need some input - unusual receiver overheating issue

Post by AsOriginallyRecorded » 07 Jul 2019 20:25

Some cautious testing of the unit after it cooled...as suggested, introducing different output devices to ascertain function would go a long way toward determining the actuality or extent of any damage. Tinkeroo's comment about the volume setting during this episode is critical as well...are you sure the unit was not being driven hard by the daughter, then left at a high level without any output devices connected? The transformer would still try to provide power, and power that doesn't produce sound driving a speaker produces heat. Thus far, too little information, and too many gloom and doom pronouncements, and possibly undue and undeserved bashing of the tech. I wouldn't get too paranoid about your unit just yet. I will assume that the tech used has a good reputation, and wasn't just picked at random. Too many unknowns.....some, all, or none of the guesses so far may actually apply to the problem. Very interested in what you discover upon opening up the unit (if necessary). In solidarity and support, from another vintage fan. #-o [-o<

Adamo0926
senior member
senior member
United States of America
Posts: 429
Joined: 26 Feb 2011 03:22
Location: Connecticut

Re: Need some input - unusual receiver overheating issue

Post by Adamo0926 » 08 Jul 2019 14:05

I was over at my friends last night and I brought with my a Yamaha CR-620 receiver. I think I figured out pretty much what happened. I'm heading out the door at the moment to drop his receiver off and also his speakers. Will explain later....I think there is good news but also bad news.

Post Reply