"Ray L. Volts" wrote in message
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"Ray L. Volts" wrote in message
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"Davy H" wrote in message
ups.com...
I have a SONY a home Cinema system (STR KSL5) which after about 2 mins
shuts down with the word PROTECT in the display screen. I have checked
all the speaker outputs and they are fine, no shorts. I have removed
all the speakers and the same problem occurs. The fan works so doesn't
seem to be an overheating problem. This PROTECT fault occurs even when
the volume is turned right down therefore not driving the amp. Anyone
have any ideas what might cause this fault? and how to rectify it?

Thanks

Davy H


Sounds like an overheating (i.e., thermal intermittent) prob to me if
it's shutting down after 2 mins. That the fan is functioning doesn't
preclude a thermal defect in one or more components.

Get a can of component chiller (Freeze-It, et al) and spray each
component in the amp chain, beginning with the higher-current devices at
the final output stages. Allow the chilled part to warm up before
proceeding to the next one.


This is what I get for usenetting when I'm barely awake. Obviously, if
the protection circuit has shut down the final stages, they won't warm up
again until the thermal fault is corrected, as power is likely not being
applied to them. You may have to give blanket coverage to several
components at once to bring the unit out of shutdown. Once you've
determined the general area at fault, you can hone in on the specific
part(s) that is/are causing the problem.


Bad joints on the output IC pins are very common on Sony A/V amps, and cause
the unit to go into protect like this

Arfa