[Amps] Strange Loading Issue

[Carl]

Id start the next step using a dummy load and investigate the bandswitch 
wiring. There is a fixed 170 pf C used on 40M but with 800pf variable I 
cant see that being the problem. More likely the load cap switch wafer 
has zapped or a crystalized solder joint.

Carl
KM1H

----- Original Message ----- 
From: "Lee Buller" <k0wa at swbell.net>
To: <amps at contesting.com>
Sent: Thursday, November 20, 2008 10:10 AM
Subject: [Amps] Strange Loading Issue




My friend has a AL80A...generic amplifier. In fact, I sold it to him. He 
was having some issues loading it so I went over to his house and took a 
look. This amp worked great for me for about 5 years or so.

We were going into a 40 meter antenna which gave an SWR reading of 1.1 
to 1. Very low. Seemed to me to be OK.....

The amp would go to 400 mills and 160-170 mills on the grid with about 
73 watts of drive. Around 600 watts. I could dip the plate and see the 
peak on the watt meter. Seems reasonable to me. But, the load control on 
the amp had no effect on the grid current or the plate current. I could 
almost put the load control anywhere and it would not affect the meters 
what so ever. Now, this had never happened to me before when I owned the 
amp. The load control was .... working normally to my thinking and I 
could adjust the load of the amp and bring down the grid current to 
around 120 mills. Kind of has be baffled as to why it is doing this. I 
do not think it is normal.

Does this "august" group have any words of wisdom?

Lee - K0WA


In our day and age it seems that Common Sense is in short supply.  If 
you don't have any Common Sense - get some Common Sense and use it.  If 
you can't find any Common Sense, ask for help from somebody who has some 
Common Sense.  Is Common Sense divine?
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