Sony Audio amplifier takes long to "warm up"

[[email protected]]

I have a background in electronics but not in audio amplifier.
I have a Sony Audio amplifier, a 25 years old model. I turn on the
power and it takes 20 to 40 minutes to hear the music. Just before I
hear the music, There is a ZZZZZZZZZZZZZ then a CLICK. Each selection
(Tuner, Aux or Tape) works or does not. Once the amp works, it works
until I turn it off.

On what stage, from the power supply to the audio output, I should look
at?
What type of component I should look for ( capacitor, relay,
transistor)?

Do you have a suggestion of a web site?

The purpose of this posting is to understand how an audio amplifier
works to repair it.

 

[Travis Jordan]

The purpose of this posting is to understand how an audio amplifier
works to repair it.

http://electronics.howstuffworks.com/amplifier.htm

 

[[email protected]]

I have a background in electronics but not in audio amplifier.
I have a Sony Audio amplifier, a 25 years old model. I turn on the
power and it takes 20 to 40 minutes to hear the music. Just before I
hear the music, There is a ZZZZZZZZZZZZZ then a CLICK. Each selection
(Tuner, Aux or Tape) works or does not. Once the amp works, it works
until I turn it off.
On what stage, from the power supply to the audio output, I should look
at?
What type of component I should look for ( capacitor, relay,
transistor)?

Electrolytic capacitors, probably. I'd guess in the power supply, the
audio output and the protection circuit.

 

[Leonard Caillouet]

Sounds like a weak cap on the relay drive circuit.

Leonard

 

[sofie]

a good possibility.... or just as likely: cold, cracked or otherwise faulty
solder connections on pcb near and around the high heat producing power
resistors, semiconductors, etc.

 

[Dave Plowman (News)]

I have a background in electronics but not in audio amplifier.
I have a Sony Audio amplifier, a 25 years old model. I turn on the
power and it takes 20 to 40 minutes to hear the music. Just before I
hear the music, There is a ZZZZZZZZZZZZZ then a CLICK. Each selection
(Tuner, Aux or Tape) works or does not. Once the amp works, it works
until I turn it off.

Sounds like the speakers are fed via a relay - commonly to prevent a thump
in the speakers at power up time. There will be a timing circuit
associated with it. May be even they trip out if there's a large DC offset
through the amp.