Gents,

I have acquired a Drake TR4 with power supply that track accurately on 80,
40, 20, 15 meters. The dial on the three 10 meter bands indicates about
30khz higher than actual. I have tried to adjust the touchy L2 accurately,
looked at T1 for problems and swapped V1 tube. There are no cracked ferrite
cores. Other hams on the air have told me this is typical of this TR-4 gear
on 10 meters.

Is there a component or gimmick that would bring the 10m tracking back on?
Does having the 6JB8 PAs screen and plate B+ disconnected affect the 10m
band in this way (I would think not)?

What am I overlooking?

Thanks,
Paul.

"Paul P" wrote in
message news
Gents,

I have acquired a Drake TR4 with power supply that track accurately on 80,
40, 20, 15 meters. The dial on the three 10 meter bands indicates about
30khz higher than actual. I have tried to adjust the touchy L2
accurately, looked at T1 for problems and swapped V1 tube. There are no
cracked ferrite cores. Other hams on the air have told me this is typical
of this TR-4 gear on 10 meters.

Is there a component or gimmick that would bring the 10m tracking back on?
Does having the 6JB8 PAs screen and plate B+ disconnected affect the 10m
band in this way (I would think not)?

What am I overlooking?

Thanks,
Paul.
Paul -

A frequency counter could quickly diagnose this issue. Have you checked the
crystals? The LMO may be working correctly.

gb

gb wrote:


A frequency counter could quickly diagnose this issue. Have you checked the
crystals? The LMO may be working correctly.

gb


I'm firing off a reply before I get the schematic D/l from Bama but this
reminds me of a problem I had with my old HX-50A.

I wouldn't be quick to blame all 3 band xtals to just go bad in the same
way...and it would seem that the LMO is ok. But my old Hammarlund had a
common coil in the osc ckt that when mal-adjusted pulled the 10m xtal
freqs WAY out of whack.

Food for thought. Its hard to find a TR-3/4 anymore that hasn't been
subjected to attempts to put it on 11 meters and the 10 meter alignment
has been goofed up.

-Bill

It sounds to me lile your oscillator might be misadjusted such that it
is oscilalting on the fundament rather than the 3rd overtone. If you
are lucky just tweaking the oscillator coil will snap it back to where
it belongs. As the other guy pointed out, though, the oscillator
might have been monkeyed with if some CB'er tried to modify it.

Also there is a better source for the TR4 manual, with better
schematics. Look for TR-4C_Manual.pdf on Google.

Rick K2XT

Bill wrote:
gb wrote:


A frequency counter could quickly diagnose this issue. Have you
checked the crystals? The LMO may be working correctly.

gb


I'm firing off a reply before I get the schematic D/l from Bama but this
reminds me of a problem I had with my old HX-50A.

I wouldn't be quick to blame all 3 band xtals to just go bad in the same
way...and it would seem that the LMO is ok. But my old Hammarlund had a
common coil in the osc ckt that when mal-adjusted pulled the 10m xtal
freqs WAY out of whack.

Food for thought. Its hard to find a TR-3/4 anymore that hasn't been
subjected to attempts to put it on 11 meters and the 10 meter alignment
has been goofed up.

-Bill
Could also be a capacitor that changed in value.