Joe -
OK. Did you try Paul's suggestions to check the RF/IF sections? The
Calibrator can vary 10 dB or more from one 100 kHz marker to the next,
so try a couple. C126 is also a potential problem, although it usually
presents as intermittent, sharp shifts in level. But if it's already
been through that ...! C126 is a large, 'film' style cap on the board
in the left rear corner, (under the power transformer,).
I finished the 13 tube version of the CD, and it will be available when
I return home after the holidays. I'm trying to decide how to market
the two versions of the 'A'. It's currently two complete CDs, one for
the 11 tube receiver and the T-4X, and another for the 13 tube version
with the T-4X. I'm thinking $25 for either, or perhaps a combined one
for $40. I don't know how much longer I'm going to be able to hold the
$25 price, I KNOW there's 'no inflation', but everything "I" buy has
gone up, including the postage cost tripling!
I sent you a 13 tube schematic from the CD, I think it's the one for
your unit. As usual, there are three schematic versions, PLUS
apparently some undocumented changes after the 'last' schematic
published. Bill Frost said that there were quite a few changes that
came out shortly after the 'last' schematic, and it was close enough to
the end of production that he didn't believe there had been another one
published. There is another copy of the last schematic on the CD that I
updated to reflect changes present in the 6.6k something receiver that
was the model for the CD, which is pretty near the end. The R-4B
started at 7000, so not much left.
By the way, that's a 6GX6. I also forgot to include the 12AV6, which
contains the AF Preamp triode, and is a likely candidate.
73, Garey - K4OAH
St Charles, IL
Drake Service Supplement CDs for
2-B, 2-C/NT, A, B and C-Line,
TR-4 and TR-4C
Joe Loverti wrote:
Thanks for all the input/suggestions... much appreciated!
Here's an update:
ESR of the 6EH5 cathode cap (10mf/25V) is: 97
When I jumper in a replacement: (10mf/16V) cap there is a slight
noticeable increase in volume.
Voltage at the cathode pin reads: 2.99 Volts
Both the 6EH5 and 6GS6 tubes check OK.
Direct substitution with a new 6EH5 makes no difference.
I don't have a new another 6GS6 to test in circuit.
Where can I find a 13 tube schematic? I'm having trouble locating the
other components mentioned to check.
Yes. I know I need to buy Garey's CDs !!
WW8X
Joe Loverti Sr.
Miamisburg, Ohio
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
