Welll...no it was not unlocked. I know what that looks like. and it
was /is 33MHz and 17MHz when fixed Rx is depressed.
This was stable, normally operating in all other senses but wrong frequency.
It must have been getting bad selection information out of the band
select switch because once I applied a small amount of deosit to the
bandswitch, it is now fine.
Curt
KU8L
Garey Barrell wrote:
Curt -
This just means that the 'low band' VCO is unlocked. The 'low band'
VCO covers 14 MHz and down. You should read about 17 MHz rather than
12, which is probably why it's losing lock. If you switch to any of
the 'high' bands (21 and up) and depress the FIXED - RCV button you
should see ~32 MHz, and any of the 'low' bands (14 and down) should be
~17 MHz. Of course both are 'wandering' frequencies as this is the
VCO's running 'unlocked'.
One common problem that can cause this is a loose or missing core top
half on the DC-DC converter transformer on the power supply board just
behind the GAIN and DELAY adjustments. The transformer core consists
of two halves, each 'E' shaped, super-glued together, 'facing' each
other. If the top half becomes loose or even falls off, the +25V
supply drops considerably. So if you look at the transformer on the
board, you should see a solid bar across the top. If you see three
square legs sticking up, check the bottom cover for the transformer
core top! If you see the 'bar', make sure it's tight to the other
half. You may touch it and have it fall off. A few drops of super
glue will fix it.
If this is NOT the problem, check the +25 VDC bus. If it's good, then
something has changed the VCO 'unlocked' frequency and you'll need the
service manual information to find out if it's an adjustment problem,
or some other failure.
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>
Curt Nixon wrote:
GM All:
Hope you all are keeping warm. 10F here and all antennas iced up.
Have a problem that just started over the weekend with the TR7 here.
All works fine except when I try to select 14MHz. the display goes
to 12xxxx MHz.
If I start at 21 and step down with the 500K dwn button, it goes to
14500 and then the next step goes to 12000 stepping back up 14 comes
back on.
I havent checked yet to see if it is actually running on 14 but
displaying 12 but it is stable there...not flickering or anything.
Common problem?
Boards have not been re-seated in a while but rig has not been stored.
Use this rig nearly every day. and it has been running great.
Curt
KU8L
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