[Drake] T-4XB Reduced power output

[Dan W. Dooley]

My T-4XB is not putting out the power it used to.  This is a very recent
thing.  I made the conversion to 6146 tubes in the PA about a year ago and
until now I was able to get 100+ watts out on 80 - 15 and maybe 80 watts on
10 in Tune.  On CW I was able to get MUCH higher.  Now, In the Tune mode I
get about 90 watts at most 80 - 15 and about 60 on 10.  CW output is lower
as well.

I've checked the RF stage tuning on all bands for maximum peaking and also
the tuning of the previous stages per the manual instructions.  Yes, I've
also carefully checked PA neutralization.

I measured the DC voltages and find that in non-xmt mode, they're pretty
much with the book.  650 VDC on the high B+ for instance.  The thing I
notice interesting is that when I key the rig to full power, B+ drops to 600
volts.  Don't recall if I ever checked that before so I don't know if it's
different than before.  Also, the ripple component is 20 volts PP as
measured on the scope.

I did replace all of the electorlytics in the AC4 PS a year or so ago and
the rig has been powered on and used a lot since that time.

Ideas?


Dan W. Dooley  WB5TKA  Bedford, Texas
   e-mail to: dandooley@pipeline.com
   Web address: http://www.qsl.net/wb9tka
May Goddes love blest ye alle