RK 56 squeals on any radio

ponyboy6039 · #377931

Hello all this is my first post for my work location I'm the microphone guy and one of my co-workers gave me a Telex Road King is an original and no matter what radio you put it on its squeals and I'm not quite sure what the problem is I checked all the connections and everything is clean and tite, the guy that put a new cord on it seem to do kind of shoddy work any ideas I would appreciate it thank you much

1206FL · #377934

Could be wired wrong. Check that the wiring is actually correct as far as pin out on both ends. What type connector does it have? A 4 pin cobra style mic plug? It may be wired for a specific radio. Just my guesses.

#377936

Hello ponyboy6039,
Welcome to the forum. It would help to know what radio you are trying to wire too. An old Telex Road King is a 4 wire microphone and will not work on some radios requiring a separate switching ground, that is causing the squeal.
As a new member could you post a intro in the "Welcome to the Forum" topic, [Please login or register to view this link] , so others can say "Hi", thanks.

3's

Greg

ponyboy6039 · #377973

Wired to a cobra Uniden 4 pin the microphone worked fine for some time and then gradually started to squeal I'm thinking it might be the capacitor or the little Transformer beyond that I'm kind of at a loss but it is the mic that squeals not the radio

#377977

How long does the radio need to be on before you detect the squeal? If it works fine and as the radio warms up starts to squeal, it's more the radio than the mic. Inside the mic there is a cap but disc caps rarely go bad. Last question, does the radio have talkback?

3's

Greg

ponyboy6039 · #377992

I ruled out the customers radio because the microphone does the same thing on my radio

1206FL · #377993

Well at least it's not the radio! Try looking at both ends of the mic. Both at the plug and at the mic itself. Possibly a pinched wire somewhere shorting out. If you or the customer had the case apart, it's possible a wire was pinched or is shorting out. Recheck all solder joints at the mic and plug as well as ohm each wire of the mic out to make sure there isn't a short in one of the wires. Hope you get it resolved.
Have you tried to re-wire the mic with a new mic cord? Might not be the issue, but I've had a magnum power mic that a wire got pinched and shorted the radios mic plug at the radio. Need to send it out to get fixed as a matter of fact. Just have so many other radios that it's no hurry.
But at any rate, hope you get it resolved. The new RK56 mic isn't like the old ones!! That is for sure. Again, good luck with getting it fixed. Have a great day.

#377995

It might be worth looking inside the mic, it is old, probably 40 yrs. I don't remember what exactly they had in them, usually they have a .01 disc cap across the mic leads as a filter and to clear up some distortion, and probably like 1206FL said, could be the cord.

3's

Greg

sonoma · #378000

a bare wire in the mic plug can cause this also if it is touching the metal part of the plug. do as every one as said and check the connections inside the mic and plug. there is not a quick cure of some one just telling you to check this wire or check the cap/. if done right you have 6 wires at the plug and 6 wires at the mic end that could be causing you this proble. there is so many guy's on this forum willing to help you so just look for what they all have told you.

1206FL · #378003

Couldn't agree more Sonoma.

#378005

I think the old Telex (Turner) Road King was a 4 wire microphone.

3's

Greg

sonoma · #378006

he said some one put a new cord on it so no telling what is on it now. may not even have the mic wire inside the braid used to feed the radio and that can cause a lot of feedback if not done right. could cause a nice squeal also if the audio wire is not inside the braid.

#378007

Yep, I missed that post. That is the best possible answer there, I'd rewire the mic ands make sure the correct wiring is used.

3's

Greg

sonoma · #378008

a couple years ago I had one acting like this one and the shield was used as the TX wire. some one just soldered wires in place until it was acting like it would work. they brought it to me to look at and after I spent a little time looking it over found the mic had been rewired. asked the guy about that and he said he had tried to replace a broken cord and it was not working right after he put the new cord on it. the one he used had a yellow inside the shield and he was not aware of the audio wire had to go inside the shield so he just played with different wires until it started to work. then he had to turn the mic gain down to stop the squeal but it still had some squeal.

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