Helmut, et. al.,
I don't have the schematic in front of me right now and am working from
memory...
I would suspect that the bias zener diode is shorted. This 7.5 V zener bias
diode is stud-mounted to a heatsink next to the filament transformer. This
might explain why your ZSAC (500 mA) is so much higher than normal (180 mA).
I have to echo the previous comment that if you still got QRO out, that the
tubes are not shorted...
I am not sure why the tube is showing plate current in standby. This could
be due to a problem with the bias switching relay. This relay is located in
the aft portion of the amp, between the rf-in and rf-out.
Not sure without looking at the schematic, but I believe the stock TL-922
uses 100V switched via the bias relay to cutoff the tubes. You might also
check this...
After repairing your amp, I would suggest that you modify it per the
information available from Rich's (AG6K) web page - I highly recommend ALL
of them. The qsk mod makes the amp much more pleasant to operate because
you won't be able to hear it switch from standby to transmit...
73, Hals u. Beinbruch!
de ki6sz
-----Original Message-----
From: Helmut (DF7ZS) [mailto:df7zs@gmx.net]
Sent: Thursday, February 24, 2000 6:34 AM
To: AMPS@contesting.com
Subject: [AMPS] Blow TL922
Hi there.
I have a TL922 by Kenwood and the folowing happend to it:
On Standby-Mode (after some minutes operation) I heard
a loud "bang" . As I looked on the panel the IP-Meter was
showing 500mA. Remember the Amp is set to STANDBY
not to operate nor the PTT is hit.
My guess was maybe a missreading so I pushed the PTT
and sended out a short burst via mike. The Power meter
showed that the AMP is delivering about 1000 watts as
normal. Back to standby - the IP reading is still 500mA.
I turned the thing off.
Any Ideas what happend ?
Anyone had a simular problem in the past ?
I am also seeking for a Service Manual to
download or faxpoll.
Thanks for any help !!!
73sss
Helmut (DF7ZS)
____________________________________________
<A>bort, <R>etry or <I>nfluence with larger hammer !
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