donskister wrote:
I went to my friend he ask for my help if i can repair his kenwood
model RX-39 audio system. I turn on the power then it seems the unit
have no problem but after 3 seconds the unit turn off and the message
appear on the display ( Protect )..I noticed after repeatedly turn on i
hear a clicking sound inside the unit before the unit turn off..I plan
to open it by next week so that i can first gather informations before
i try to repair it.

By the way... My friend told me that sometimes he can used the unit
for a couple of months when he will not used the unit for a weeks then
after the unit will fail again then he will not used the unit for a
weeks..... it seems that the unit is working if had taken a rest.



It could be a cracked solder joint, you have to be careful working on
audio amps, sometimes the protection circuit will save them, sometimes
they suffer a catastrophic failure and then you're looking at new output
transistors and a whole pile of parts they take out when they blow.