[SECC] Adjusting tuners

[Tom W8JI]

> on the 756PRO. I need to buy a new headset with the Icom 'IC' element in 
> it.
> About 20 mins in I notice a burning smell. My MFJ 901B tuner is arching 
> over
> on the switch that is used to switch in the different inductances. I 
> opened
> it up and it was totally fried. (running just 100 watts.. what junk !!)

Here are some very simple useful tips for anyone using a conventional T 
network tuner:

There are a nearly infinite combination of settings that can produce a 
match.
When you adjust any T network tuner, try to always start with maximum 
capacitance. Always use the maximum possible capacitance, and minimum 
possible inductance, that allows a match.

If the user somehow manages to use very low capacitance, voltage inside any 
tuner can become very high even at very low power. A tuner that can handle 
600 watts when properly tuned can fail at 60 watts when mistuned.

Learning how to adjust a tuner will greatly extend the life of any tuner. We 
need to remember is one thing....use maximum possible capacitance and 
minimum inductance that allows a match.

> figured I would just stop and go ahead and make the repairs to my Dentron
> Super Tuner that I bought parts for in Huntsville.

When repaired, adjust the Dentron as suggested above and it may never need 
repair again! Always remember one simple rule.... minimum inductance and 
maximum capacitance that allows a match.

73 Tom