[Boatanchors] TX4C problem

[Garey Barrell]

Bill -

Yes, the 6EJ7 is an 'iffy' tube, even NOS.

You should check your dummy load...  those are pretty excessive output powers for a T-4XC, and 
would translate into almost 500 mA of plate current.  Consider Drake specified a MAX of 350 mA 
on most bands.  Or, how much reflected power do you measure with the Bird?

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

Bill Abate wrote:
> Bill,
>
> My T-4XC needed a 6EJ7.  After an alignment I got 150 to 165 watts into a dummy load measured 
> with my Bird wattmeter on all bands. That 6EJ7 made a big difference.  Not sure why yours is 
> so low but the finals seem to be a good candidate.  Also I found a NOS tube did not help the 
> problem when it should have.  When all else fails don't rely on a single tube sub.  Check RF 
> voltage at the 6JB6's grid on each band.
>
> 73,
>
> Bill, K3PGB
>
> Bill and Liz wrote:
>> I have been playing with a drake TX4C and, after going through the
>> complete alignment process a couple of times, a strange problem
>> persists.  I believe the PA tubes to be weak-power output on 10M is
>> around 50W in CW mode.  But the radio makes 90W on 160M in spite of
>> the fact that there is not enough C in the loading cap and about the
>> same on 80M where the loading cap does peak nicely.
>>
>> However, on 40M there appears to be considerably more drive available
>> and power output runs 130W at about 375 ma which I read as being
>> normal.  It is less on 20 and 15-around 90W or so output.  I see only
>> a bit of power sag key down on 10M.
>>
>> Can anyone suggest why there is so much more drive on 40M?  Is this
>> condition characteristic of the TX4 series?
>>
>> Bill VE3NH