[Amps] tuner anomalies

[Dan Sawyer]

The topic is a Murch Transmatch 2000. It is in 'better' condition with 
no signs of internal arcing, etc.

The background: I am tuning a long wire, about 100 feet long. I tune 
with either a 0 dbm generator, a directional coupler, and a scope or 
with a network analyzer. Those both work well and they both show the 
same tuning results, that is a min return on one will also be a min on 
the other.

The issue is: When a small about of power, a watt or less is applied 
things work well, the SWR is close to 1:1. However if more power is 
applied the 'tune' point jumps a couple of hundred kc and the SWR jumps 
accordingly. The tuner has 4 sliding contacts, one each on the two 
variable caps and two on the variable induction. Those have been 
cleaned. I am not sure where else to look.

This setup worked very well for several months. This behavior just 
started a few weeks back. I am at a loss as to how to analyze what is 
happening.

Thanks - Dan