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harmon Kadon receiver HK930 twin power receiver heated up

lwong2's picture

can some one kindly advise me what likely has gone wrong and how shall i trouble shoot. Bearing in mind i m a novice in electronics.

The left channel of this receiver is getting very hot after i used it for about 30 mins. The left channel heat sink and the left channel transformer are also getting v hot. The right channel is normal. I measure the DC voltage at the left channel. It rises as the temp gets hotter.
This problem was caused by after i replaced 4 pcs (2pc each side 220 uf 16V) of elna similic II ecaps and the power cables (8 guage).

Appreciate if some one can help me to trouble shoot this problem

Thank you and best regards,


Re: harmon Kadon receiver HK930 twin power receiver heated up

Sounds like your audio bias adjustment is way off or there is a problem in the audio power amp. Bias adjust is R601 for the left channel, but you need to set it according to instructions (listed under 930 in the library here). It is possible there are still bad parts in the amplifier, like the bias diodes (D601, 2) or any part in that circuit. You have to assume it was once set properly, so parts may still be bad. Are you certain you got the capacitors installed with proper polarity? You may want to let a tech deal with this problem, as a mistake may take out your output transistors.