Connex 3300HP-ZX

[dbreed]

Let me start by saying I have owned this radio for nearly 7 years and have never switched if from the AM CB Channels to the 10 meter side.

It has been tweaked, by an older radio guy that put an led lamp where there had been either a jumper or a diode or resistor. I can't remember what was there it has been so long ago.

Anyway, I use an RK56 with it and have always gotten compliments on how clean it sounds.
I used to mix live audio on the Strip in Vegas from 1976 to 1998 and I never use the echo on a vocal mic unless the talent is singing.

I don't sing, so I don't need no stinking echo.

Now, this past week I have noticed I am having a problem with the unit.

Whether I am sitting still or driving, at times the radio signal just disappears. You know, that faint "sizzle" noise you hear when it is on?
Just stops.
At the same time this occurs, if I key up, I get no swing on the meter and the Tx light does not go from green to red.
I do hear a faint click in the ext. spkr.
But no transmit.

Now, if I wait it will come back to "normal" and I can key up.
Or, I THINK, if I tap the radio lightly on the case, it will come back to "normal".
However, that could be a coincidence, because it does not always come back just because I tapped it. I might tap it 2-10 times and then it comes back.

So, I disassembled it yesterday and thoroughly inspected every connection, plug, traces on the circuit boards and solder joints.

I could find absolutely nothing that seemed out of place.

I reassembled it and it is still doing this cutting out whenever it wants to.

Suspects;

A weak capacitor or one that has broken down or is breaking down

A diode that gets too warm, while NOT transmitting and goes "open"

Some other component reacting to heat that goes open and then cools and closes.

I don't know.

I graduated from AC/DC Fundamentals and Electronics in 1971 but have never been a ham or an electronics engineer.

I know a little about radios but not enough to chase a signal without a Sams' Photofacts schematic, a signal generator and and O-scope, none of which do I own nor have I touched any of those in over 30 years.

You Kcorey, seem to have a great deal of knowledge and experience and I would appreciate your help if you have some ideas.

Or, you may blow me off because I own an illegal radio.

Then, I won't go a way mad, I'll just go away.

Thanks in advance.

CB KAEC0503 since 1975

[kd5drx]

SOunds like your on the right track with something heating up and going open or closed my suggestion is a hair dryer and a can of canned air turn it on on the bench and take the hair dryer and start heating up small parts of the board 1 at a time till it cuts off then cool it down with air and see if it comes back on. this should reveal the weak part. it may also be a cold solder joint that only now showed up after years of flawles service but certain conditions have now been met that will make it show up. THese kind of troubles on any radio are hard to find and some times are time consumeing to find and treat so allot of your cb butchers will not take the time to find. You can get the sams for the radio pretty easy. or you can send it to a place in Michigan that i know will fix it. it may take some time for them to get to it but they have been in buisnes for years and have allways been good to deal with. if you want there name and address drop me a note to [LINK POSTED BY MEMBER] Only Members Can View This Truck Forum Link. and i will be glad to give it to you.and yes i am a ham and yes the radio is ilegal but fixing one of those old radios is worth it in my opinion as long as you stay under 28.000 meg and above 26.000 meg you will be ok the FCC will one day start policeing the (freeband) as we called it in the old days. Good luck.