On Tue, 13 Oct 1998 17:47:56 +0000 N9YXA-Cedrick Johnson
<n9yxa@amsat.org> writes:
>
>Hello-
>When I came home and tried to tune up my amp, the rig's SWR meter
>pegged,
>and the plate current read 400 ma, and the grid was right in the
>middle
>with NO POWER applied, except for the keydown. The external meter read
>0
>watts also. Can someone tell me what has gone wrong?
Sounds like a tube might have blown or a grid circuit component. Check
the 33 Ohm resistors and 200pf capacitors at each socket.
While ur at it check the resistor values in the parasitic suppressors.
Cetron tubes are usually very stable in that amp as well as many Chinese
brands. Svetlana can get wild at times.
Trying one tube at a time may help to localize also.
If you have a voltmeter you can check the bias voltage; it should be
about -125VDC in standby and around -5VDC when keyed. If not there may be
a bad electrolytic in the bias PS.
GL Carl KM1H
>
>I also noticed that if I switch it to the 80M position, the SWR drops,
>but
>it keeps rising and falling.
>
>This is on all bands.
>
>-Cedrick
>===============================================
>Cedrick Johnson, N9YXA, Z2/N9YXA
>Aurora, Illinois
>Computer Software Specialist
>10-10: 67368, SMC, ARRL, FRRL, ISTHC, EARS
>Visit the N9YXA Contest Station online at:
>http://www.qsl.net/n9yxa
>
>"Resistance is futile!" -Dilbert/Dogbert
>
>--
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>
>
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