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Hafler DH-500 in Protection

Solid State | Audiokarma Home Audio Stereo Discussion Forums - audiokarma.org
Not really familiar Hafler equipment and this one has me stumped. I've looked at several other threads about this same topic, but I'm not having much luck. This DH-500 came to me this way - powers on, switch light is solid, but does not come out of protection. I've replaced capacitors and transistors on both channels of power amp, and replaced caps, tranisistors, and diodes on protection board (PC-9A). Also replaced Protection Relay with NOS relay.

Transistors Used:

2N5550 --> ZTX694B

2N5401 --> ZTX795A

Diodes were straight ahead replacements (1N5240B, 1N4003, and 1N4148). Caps were also value for value.

I measured DC at one side of the relay and got ~20mV; I jumped the relay and have good output for prolonged listening without excessive heating, but I'd rather keep the relay in circuit.

Do you folks have any advice?

Thanks,

Dan

 
Date: Jan 12, 2018   


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