Joe -
VERY good point!! I sometimes don't go far enough 'back'! :-)
ALL buttons on the front panel should be OUT to start!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Joe Pyles wrote:
Also make sure the Fixed buttons on the front of the radio are not
depressed, and check that the PTO is indeed putting out a signal as
the synthesizer won't lock without PTO input.
73
Joe KC9LAD
At 10:06 AM 12/18/2009, you wrote:
Adrian -
Changing the pots to multiturn will have NO effect upon the
synthesizer operation. Again, it doesn't hurt, but isn't
_necessary_ for proper operation.
You definitely have a synthesizer problem, either in the VCOs or the
reference frequencies.
Verify that you have the 500 kHz reference, and then check for the
500 kHz input from the divider chain.
Jim's suggestion to check the 24 VDC supply is a good one. A common
cause of failure is the top "half" of the DC-DC converter transformer
core falls off, or just becomes separated enough to cause the voltage
to drop. Looking at the "top" of the transformer on the Power Supply
board (one with the pots), you should see a solid bar. If you see
three "ends" of an "E" sticking up, look for the top half of the "E"
shaped core in the bottom of the case. If gone, replacements can be
had from Charlie, K3ICH.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com <http://www.k4oah.com/> >
Adrian Rees (MW1LCR) wrote:
Hello all
I have the Service Manual and have it printed out.
To confirm the symptoms, on 21 and 28MHz the counter settles around
33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can
"hear" my signal generator on thes frequencies (sweeping the generator
through the 33 and 17MHz frequencies). With an external source the
counter
works fine.
So the synthesizer doesn't appear to be locking. I have cleaned the
Molex
connectors. My next course of action is to replace the pots on the
voltage
control board for multiturn ones, and re-align the voltages etc, and
then
re-check the synthesizer board again.
Thanks all for the help, so far !
Adrian MW1LCR
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
