CED VideoDisc and Player Discussion

[CarolinaTKE]

Hello! I've been a member of the forum a while, but this is my first post. I have a 250-series CED player that works when it's in a good mood and about 800 discs, but right now I have a Dimensia question. After a long search, I managed to get my hands on a MSA100 amplifier to go with my CD player and tuner. The amp was still in the box and is in great shape. My question is this: is it normal for the unit to be warm while idle and HOT while in use? I'm accustomed to a little heat coming off appliances, but the power supply area seems to be warm even after it's been off for hours and it's HOT while it's running. There's also a faint buzz and the display shows a few glowing lines when it's off. It works perfectly when it's hooked up and the sound is fantastic, but I'm worried that something is wrong with it. Is it being normal?

Thanks!
Andrew

[rsrendfeld]

If the amp is so hot you can not rest your hand against without discomfort it is too hot.
I don't know about the buzzing noise; mine has a very faint hum wen it is in use.

[Rixrex]

My son and I both have the same model Denon amps. His would heat up too much and eventually trigger the protective circuit that turns it off. Mine works fine. Replacing the transformer circuitry is way more than the amp's value, so several years ago we installed a small PC-style cooling fan on his, and now it works fine all the time, and I put another on mine. Keeping a transformer cool is important to extending it's life.

Maybe something like that will help yours in lieu of costly repairs, or trying to replace non-existent parts, for the time being. Buzz sounds like it might be 60 cycle hum, and that would be consistent with transformer symptoms.

[CarolinaTKE]

Thanks for the comments. I have a little desk fan that I've been keeping aimed at it and it's been plugged in for 48 hours now and is staying only mildly warm--about as warm as a 12 volt power adaptor. It's still playing perfectly, so I'll just keeping using it as it is unless something changes, then I might try that computer fan idea.

[Reinhart]

Heat is actually a normal condition for certain amplifiers unless they interfere with normal operation (I.E. Protection circuit kicking in).

But, one thing to check, particularly with older amps, in regards to overheating, particularly with overheating of the primary transformer are bad mains electrolytic capacitors. These are the BIG barrel capacitors responsible for storing energy reserves for amplifier demands.

When these dry up, which can be typical of older amplifiers, their capacities will diminish. If they completely go out to the point where they go open circuit, the amp may no longer function (as was the case of an old Sansui receiver I saw once before). But, when there is still some reserves left but not enough for the amplifier, guess what part of the power supply gets strained for the amplifier's power demands?

In addition to checking the mains capacitors, I would also check out any other caps that could dry up, particularly those that get exposed to heat, such as any capacitors in the secondary (or standby) power supply if so equipped.

As for the people with the Denon amps overheating, I would do some checking of the speaker connections for any shorts and/or oxidation of the speaker leads. For oxidized speaker leads involving bare wire, I would cut off the oxidized wire, then expose new bare wire followed by solder tinning as a preventative.

I would also check the speakers and their impedance compared to what the amplifier is designed or configured to serve. If the speakers have a lower impedance beyond what the amp is designed or configured to serve and if the speakers are not as efficient requiring higher wattage for the volume, you can have overheating problems.

Something is causing the overheating so try to find out why rather than applying a patch to address the symptoms.

[Rixrex]

Thanks for that pertinent info. All of those things had been checked on the Denon amp that tended to get hot and nothing was initially found to be problematic. It's an oddball situation, for you'd think that it would be exactly the way you stated, that there would be a specific problem that could be resolved once it was discovered, rather than treat the symptoms, and I usually agree with that approach. But in this case, that problem was not easily discovered and would have created an expense that far outweighs the value of the unit.

That's often a consideration when deciding to go ahead with an expensive diagnosis and repair. Is it worth spending the money if that means spending more than the item's value? That's something the original poster must consider as well. For those who aren't technically adept or knowledgable, the cost of a professional diagnosis and repair can just be too much. I often find this to be the case with older vintage electronics that I use, such as laserdisc players and VCRs, Beta or VHS.

I'm not going to spend $200-$300 to fix some sort of circuitry or laser problem on my LD player when I can buy a good, operable player of the same model or even better model for less than half that price. The same is true for the VCR, I would have to spend way more to repair a good name brand VCR than to go find a well-kept one at an estate sale or such place, especially with VHS models.

Fortunately, thanks to Tom and CEDmagic and folks here like yourself, maintaining the CED players is an easier task to do by one's self.