How to fix overheating?

  • Thread starter d0ntblamecanada
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d0ntblamecanada

Guest
Hi - I have a Harmon Kardon AVR 254 and the audio recently crapped out. I have a feeling it might be from overheating since it was very hot when I touched it and the area I keep it in probably doesn't vent as well as it should. Will this fix itself if I let it cool or have I done permanent damage. The video still comes through fine, just the audio doesn't work. Thanks for any advice.
 

dante01

Distinguished Member
Hi - I have a Harmon Kardon AVR 254 and the audio recently crapped out. I have a feeling it might be from overheating since it was very hot when I touched it and the area I keep it in probably doesn't vent as well as it should. Will this fix itself if I let it cool or have I done permanent damage. The video still comes through fine, just the audio doesn't work. Thanks for any advice.

It may come back to life after leaving it to cool or you may have blown an internal fuse?

What speaker are you using, do they have a low impedance? This may have been the initial cause of the overheating?
 
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d0ntblamecanada

Guest
They are some old panasonics, not sure what impedance even is. I'll let it cool for a couple hours and see if it sorts itself i guess. Is there a way to confirm if it was overheating or a blown fuse?
 
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d0ntblamecanada

Guest
Is there a way for me to tell what kind of damage was done easily or should i just take it to a repair shop if it doesn't fix itself in a few hours after cooling? Thanks for your responses
 

dante01

Distinguished Member
Is there a way for me to tell what kind of damage was done easily or should i just take it to a repair shop if it doesn't fix itself in a few hours after cooling? Thanks for your responses

If you've no experience of electrical circuits etc, then it would be better to have a qualified engineer take a look at the unit. You may see some scorching within the unit if you remove the cover, but this will not give you enough info to diagnose the problem or repair the unit yourself, not unless you know exactly what you are looking at and how to repair it.
 

dante01

Distinguished Member
They are some old panasonics, not sure what impedance even is.

Impedance is expressed in Ohms. Ohms are usually associated with the Ω symbol.

The Ohm is a unit of electrical resistance, expressing the resistance in a circuit transmitting a current of one ampere when subjected to a potential difference of one volt.

The figures on the rear of a speaker in relation to Ohms give you the amount of electrical resistance the speaker imposes on the amplifier.
 
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dante01

Distinguished Member
I'd also recommend you disconnect all the speakers and check all the speaker wires for stray strands that may have been shorting out the amp.
 

Jamie

Distinguished Member
They are some old panasonics.

Are they speakers that originally came with an all in one system. Because they are quite likely to be a weird/low impedance if thats the case.
 

Ian Dudley

Active Member
Hi - I have a Harmon Kardon AVR 254 and the audio recently crapped out. I have a feeling it might be from overheating since it was very hot when I touched it and the area I keep it in probably doesn't vent as well as it should. Will this fix itself if I let it cool or have I done permanent damage. The video still comes through fine, just the audio doesn't work. Thanks for any advice.

Don't know if it's still dead, but before you do anything drastic with the amp try another pair of speakers. If you were running the amp quite hard and it started clipping, it could have trashed the speakers, esp if they were fairly cheap and cheerful 'all in one' type things.

This happened to me a few years back when my then GF twisted my arm into using my DB925 and mission speakers as a PA system to an indoors pool party in the summer (in reflection this was a stageringly bad idea).

It was very hot and humid in there and the volume was cranked a bit too high. Afterwards the whole system was silent and I assumed the amp was blown. But on the offchance I tried another speaker (one of the rears) and found out the amp was fine but the fronts were melted dead.
 

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