VSX-1020-K receiver repeatedly shuts down as if overheated, but is not hot at all, very free ventilation, occurs even when not on for a long time; clearly a false signal re: overheat/shutdown

Confirm that the unit has adequate ventilation.

PIONEER VSX 821 VSX 921 VSX 521 AUDIO VIDEO MULTI CHANNEL RECEIVER SERVICE...

The link provides a procedure to read the error log after a shut down

Hope this helps?

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on; or it may turn on but produce no audio to the speakers.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'nekkid'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as another possible root cause forintermittent shutdown.

Generally speaking, an amp protects itself from heat, shorts and overloads.

Overloads can be from excessive periods of high output and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced hands-on tech.

I wouldn't hold my breath waiting for free detailed circuitry.

A precise make and model might yield more-specific answer.

Generally speaking, an amp protects itself from heat, shorts and overloads.

Overloads can be from excessive periods of high output and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced hands-on tech.

Make sure the speaker wires are tight.

http://www.retrevo.com/support/Pioneer-VSX-820-K-Receivers-manual/id/23653ag912/t/2/

Generally speaking, an amp protects itself from heat, shorts and overloads.

Overloads can be from excessive periods of high output and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced hands-on tech.

If your reciever is in a tight enclosed space, than it will overheat and shut down to protect itself. Try to get some ventilation to it by either opening the cabinet door, adding a fan, or pulling it completely out of the enclosed space.

try turning up with out hooking up speakers. if it does not shut off you have a bad speaker somewhere. Receiver will be okay

You speakers are out of phase. Check to see if the polarity is correct on the receiver and the speaker. Positive (red) with positive, negative with negative (black). Also check the impedance of the speaker, it should be located on the back of the speaker measured in ohms. Make sure that your receiver matches the impedance of your speaker. You can find this in the settings of the receiver.

Aside from any intrinsic problem with your receiver, the usual suspects are;
1) Poor receiver ventilation. 2) Very high levels of bass. 3) Shorts in the speaker wiring. 4) A rubbing loudspeaker voice coil.