[AMPS] SB-200 very strange behavior

[Phil Clements]

Check the safety RF choke at the output of the amp to see if it
is open. Put an RF choke from the antenna post to chassis ground
on the Murch and see what happens. Report back.
GL!
Phil, K5PC
Subject: [AMPS] SB-200 very strange behavior


>
> Just bought an SB-200 and here's the set-up:
>
> TS530S to SB-200 (with all Harbach mods and new matched Cetron tubes) to
> SWR-power meter (checked for accuracy) to Murch UT-2000B antenna tuner to
> end fed wire antenna.
>
> Problem:
>
> With antenna connected and no drive (mike gain set to zero) and SWR at 1:1,
> on 10 Meters the power meter shows 5 watts output.  On 15 Meters 1 watt
> output.  No indication of output on SB-200 relative output meter at maximum
> sensativity.
>
> With dummy load connected, no indication of output on either band.
>
> Have ruled out parasitics as there is no amp grid current and amp plate
> current remains at nominal resting level while output is indicated on power
> meter and cannot detect any RF with sensative field strength meter.
>
> Can anyone explain this peculiar situation?
>
> Steve W2IMF
>
>
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>



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