Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Mike -
OK. Well it sounds like your VCO's are within range. It sure sounds
like the "out of lock" signal is the problem. You can measure the OOL
signal on Pin 8 of the ACC connector, or on Pin 4 of the RV-7 connector
on the rear panel. It should read about 5.5VDC in transmit and 0 in
receive. If either of these pins is shorted to ground, you'll get the
symptoms you are describing. Do you have an RV-7 connected? Pushing in
the SPOT button on the RV-7 grounds Pin 4 of the RV-7 connector. If you
DO have an RV-7, disconnect it and see if the problem occurs.
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://hr99.home.mindspring.com/R-4C_Servicez/>
[EMAIL PROTECTED] wrote:
In a message dated 5/28/2005 10:06:56 AM Central Standard Time,
[EMAIL PROTECTED] writes:
Mike -
Sounds like a VCO problem. The primary difference between the two
"groups" of bands is that they rely on two different VCOs. If the
sythesizer isn't "locked" the transmitter will not operate. What
does
the frequency readout show when the transmitter won't transmit?
You can do a rough check by pushing in the "Fixed Rcv"
pushbutton. The
frequency display should count up in frequency and then sort of
"dither"
around 17 MHz for bandswitch settings of 14 and down, and 32 MHz
for 21
and up.
It sounds like the VCO's may be running around the "edge" of their
capture limit.
There are other possibilities as well, but this is a start!
73, Garey - K4OAH
Atlanta
Hello Garey,
I think you are probable right with the VCO board. The others did
not address the 14 / 21 mhz difference. The problem did happen again
today. When it happens the frequency says the same in receive and
transmit. Say I am on 14.250 receive and try to transmit and it does
not the frequency would be the same (say 14.250). I did try the fixed
receive button. On 14 mhz it went to 17.206 dithered and slowly came
back down. On 21 mhz it went up to 32.458 dithered and then slowly
came back down. Are these frequencies close enough to what they should
be? Is it right that it will dither and then go back DOWN again? If
this is ok, are they other ways I can check the VCO board? I will try
cleaning the contacts like the others have suggested as soon as I get
the De-oxit. Many thanks for the help trying to fix the TR-7. I just
moved down to Palm Beach FL from Tulsa OK.
TNX 73 Mike WD5GLW
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