[Amps] HF-2000 amp problem?

[k7rdx]

Would not loading heavier cause the grid current to be even higher?Jim..
----- Original Message ----- 
From: <TexasRF at aol.com>
To: <Paul at PaulFerguson.us>; <amps at contesting.com>
Sent: Saturday, April 14, 2007 9:28 AM
Subject: Re: [Amps] HF-2000 amp problem?


>
> Sounds like you need to increase the drive to 50-75w like 20m and load
> heavier (less load C) for maximum output.
>
> If this scares you, load heavier first and then increase the drive  power.
>
> 73,
> Gerald K5GW
>
> In a message dated 4/14/2007 10:25:05 A.M. Central Daylight Time,
> Paul at PaulFerguson.us writes:
>
> I have a  10-year-old QRO HF-2000 amp. It has two Amperex 3-500Z
> tubes. You can see  info on it at: http://www.qrotec.com/
>
> It used to output 1,000 watts or  so on all bands. Now it outputs
> 1,000 watts up to 20 meters, but only  about 500 watts on 17 meters
> thru 10 meters.
>
> On 20 meters and  lower, grid current runs about 150 ma and plate
> current about 500 ma.  Plate voltage is about 2,800. Input power runs
> 50 - 75 watts.
>
> On  17 meters and higher, grid current is about 100 - 150 ma and plate
> current  is 250 - 300 ma. A small increase in input power gives a
> large increase in  grid current and little additional output power.
> Input power is 30 - 40  watts.
>
> The amps tuned inputs seem OK as the transceiver sees an SWR of  1.1 -
> 1.3.
>
> All measurements were taken using a 50 ohm dummy  load.
>
> Any ideas as to what might be the problem?
>
> 73,
> Paul -  K5ESW
> Raleigh, NC
>
>
>
>
>
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