Connex 3300HP & Cobra CB issues?

[SIX-SHOOTER]

I have a Connex 3300HP that I got from a friend in a package deal & it has a strange issue.On the channels it will transmit on it shows that it is transmitting on 24mhz but not a stable frequency at any time.On the low bands it will not transmit at all so I'm guessing it won't oscillate that low in frequency? Some bands it tries to key but won't stay keyed.The higher in the bands I go it starts keying.I have a Cobra 148 GTL (side microphone) & a Cobra 29 LTD that stays on the same frequency no matter what channel I put them on & it's also way out of the 11 meter band? Anyone else seen this happen or know what is going on with them? I don't usually mess with Export CB's so the Connex is something I have no dealings with.Thanks for any assistance & God bless.

SIX-SHOOTER

 

[nomadradio]

The one thing all three radios share in common seems to be trouble with each radio's PLL circuit. This is what determines your channel frequency from the channel selector setting.

But this sounds like three cars that won't start. Same symptom, but it would be a very long shot to find that all three have the exact, same cause.

Do you have a 'scope available? I have been repairing PLL circuits for more decades than I care to think about.

Just never learned to do it without a 'scope. It's my Swiss-army knife for troubleshooting this sort of fault.

Frequently we find that this kind of trouble starts with a golden screwdriver. Someone starts twisting every adjustment while laser-focused on the wattmeter.

But usually, that's among the first troubleshooting steps. Seeing that none of the routine adjustments in that section have been twisted out of reason.

73

 

[jon666]

out of lock

 

[Chevboy0167]

May need to check the crystals. Factory uses corrosive glue to keep them from flexing on the main board. They can look and feel tight, but take some measurements and or de-solder from board for a visual. Many leads fail by rot from the glue used. I have also seen this happen to the 455 filter and some other IC's.

 

[nomadradio]

I would suggest splitting this issue into three threads, one for each radio.

No way the same fix will work for all three.

73