[Boatanchors] TX4C problem

[Joe W2KJ]

I agree with Garey on the 6EJ7 tubes being flakey.

A couple of years ago I bought several NOS Phillips 6EJ7 from a reputable tube dealer on the Internet.

Either they weren't good out of the box or only lasted less than 6 months in my T4XC.

I buy only Sylvania now...RCA, GE are also good...I stay away from anything else.

			73, Joe W2KJ

On Mar 1, 2015, at 1:11 PM, Garey Barrell wrote:

> 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
> 
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