Kenwood/Trio KA-550 Amplifier

S

Steve

Guest
Hi All,

I have a Kenwood Trio KA-550 audio amp here - which powers up (LEDs light)
but has no audio output at all (not even hiss).

The transformer (and fuse!) check out ok. The rectification is also OK.

I suspect the protection circuit has gone faulty, as after turn-on the relay
fails to click. However - I'm unsure if this circuit is faulty, or if a
fault elsewhere is preventing this from 'switching on' the audio side.

I've found the service manual available online for $130 - but, even in its
working state it's only worth Ł25 ($15?).

Does anyone have any experience with this amp? Would anyone be kind enough
to forward me the service manual? I'd be very greatful for any help ... !

I hate chucking things out ... I'd rather fix it and pass it on to someone
else :)


Regards,


Steve
Bristol, UK
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NEW! Amateur Radio UK Forums:-
http://www.electro-clash.com/amateur/index.php
 
Probably a fault in one amp channel or the other, or a power supply issue,
or maybe a problem in the protection circuit itself.

Measure for a DC offset from one channel or the other, and check all your
smaller capacitors in the regulated power supply area, and in the protection
circuit.

If there's an offset from BOTH channels, it's likely a power supply issue.


Mark Z.

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Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Steve" <steve@moonfoundation.com> wrote in message
news:40a646ed$0$25317$cc9e4d1f@news-text.dial.pipex.com...
Hi All,

I have a Kenwood Trio KA-550 audio amp here - which powers up (LEDs light)
but has no audio output at all (not even hiss).

The transformer (and fuse!) check out ok. The rectification is also OK.

I suspect the protection circuit has gone faulty, as after turn-on the
relay
fails to click. However - I'm unsure if this circuit is faulty, or if a
fault elsewhere is preventing this from 'switching on' the audio side.

I've found the service manual available online for $130 - but, even in its
working state it's only worth Ł25 ($15?).

Does anyone have any experience with this amp? Would anyone be kind
enough
to forward me the service manual? I'd be very greatful for any help ...
!

I hate chucking things out ... I'd rather fix it and pass it on to someone
else :)


Regards,


Steve
Bristol, UK
--
NEW! Amateur Radio UK Forums:-
http://www.electro-clash.com/amateur/index.php
Click to expand...
 
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