[Amps] LK-500ZB

[jeremy-ca]

At first glance it sounds like a parasitic. Unwind one end of both 
suppressor coils and measure the resistors. Replace if more than 15% out of 
tolerance. The ZB is over 20 years old so a little PM is necessary.

While you are at it look over the bandswitch carefully as they have a habit 
of arcing  on the right side of the wafer closest the panel.

Carl
KM1H




----- Original Message ----- 
From: <kg7hf at comcast.net>
To: <amps at contesting.com>; <amps at contesting.com>
Cc: <amps-request at contesting.com>
Sent: Saturday, December 08, 2007 12:24 AM
Subject: [Amps] LK-500ZB


>
> Hello all,
>
> I'm looking at an LK-500ZB that doesn't seem quite right anymore.  I've 
> had the amp for about a year now and it seems to have been working great. 
> Now, I'm having a problem getting 10 meters to tune.  All other bands 
> 160 - 15 are ok, full output and what I would call easy to tune.  When I 
> switch to 10 everything goes crazy.  By this I mean that using the Plate 
> tune causes the swr between the dummy load and the amp to go up and down 
> radically.  Using the load control can produce output, but no pronounced 
> dip on the plate current.  Both the plate current and grid current change 
> violently when trying to use the plate and load tune.  This only happens 
> on 10m.  Any ideas?
>
> Thanks,
> Paul - KG7HF
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