[TenTec] TT 238C will not tune

[Bob McGraw - K4TAX]

Basically anything in line between the output of the radio and the input to 
the tuner can be suspect.  And I mean anything.  Coax jumpers, SWR/Power 
meters, LP filters, various switches,  power amps just to name a few.

The new breed of connectors we get today look really good.  Looks is the 
best description of their quality.   Electrically they are fair to poor. 
Even for the best of them, I always practice snugging them with a pair of 4" 
Channel Lock pliers.  Finger tight is not good enough.

I seem to recall that you tried another tuner stating that it worked.  Were 
you using the exact same configuration, meaning jumpers and every thing 
else.  If not then the comparison was not accurate.

As to the 238 there is a specific or preferred method for the usage.

(a) Set the capacitor to a value of 2.
(b) Set the inductor to  a full scale (fully clockwise) position
(c) Apply a small amount of power, then switch the BYPASS switch to both 
sides and observe the position giving the lower SWR value.
(d) Alternately adjust the Capacitor and Inductor for lowest reading.
(e) If the capacitor shows the lowest value when near 0, then turn S1 to the 
other side
(f) If the capacitor shows the lowest value near 10, then turn S1 to the 
next higher value

Once you obtain the lowest SWR value make a note of the values for the 
frequency and proceed to the next frequency.

You could have certain conditions, based on antenna and feedline length, 
that can not be matched with the tuner.  In this case add a few feet of 
feedline and proceed with the matching procedure.

73
Bob, K4TAX




----- Original Message ----- 
From: "denton sprague" <denton at oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Friday, July 26, 2013 10:43 AM
Subject: Re: [TenTec] TT 238C will not tune


well an update…TT tested the 238C at full legal limit and it got a clean 
bill of health…so its something on my end. I will try it again when it gets 
back, with new cables and see what happens.
On Jul 8, 2013, at 6:27 AM, denton sprague <denton at oregontrail.net> wrote:

> called TT…off it goes to the hospital...
> On Jul 6, 2013, at 10:27 AM, denton sprague <denton at oregontrail.net> 
> wrote:
>
>> Hi all…
>> I recently purchased a used TT 238C tuner from TT and other than 
>> functioning correctly in the bandpass position, it will not tune my 
>> antenna system at all!
>> I pulled the cover and can find nothing amiss…
>> It acts like the roller inductor is not in the system and the padding 
>> caps on the high z/low z switch are all not correct value.
>> Visually it all looks pretty much like new on the inside.
>> Will call Stan at TT early monday am and see what he says…good thing they 
>> warrant their equipment.
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