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Old September 12th 06, 05:21 AM posted to rec.radio.cb
Peter Peter is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 26
Default Problems with Cobra 148GTL CB radio

wrote...
Ok--I solved the problem with the radio!

Yes, it had been modified. Someone grounded pin 10 of the PPL chip and
fiddled with the VCO for above-band operation. I removed the jumper on
pin 10 and then used a frequency counter to realign the VCO.


Realign the VCO using a DMM, rather than a frequency counter.
Use the frequency counter when aligning the crystal oscillators.

As it had clearly been got at, I would take the time to check the frequency of each crystal
oscillator and the carrier balance. Depending on which version of Cobra 148GTL you have, there
could be a few crystals.
Even more important, check the output and drive bias settings. If these are not set correctly,
the transistors may not last long.


Regards,

Peter.
http://www.citizensband.radiouk.com/