The AM Forum

I have one that is 120V operated, and wanna clean the coax contacts. How do you access them?

Use your thumb nail and lift the silver cover on the end. Inside are the coax contacts. Good luck getting anything in there. In the past, I've used a piece of a $bill to clean contacts; grab  some tweeezers/hemostat/allie gator clip and have at it.  good luck cleaning the contacts.

klc

I used a Dowkey relay long long ago, and had similar problems, then I bought a Johnson T/R switch.   Sold the relay, kept the switch.   Haven't ever needed to clean the contacts either. ;D

I had a dow-key relay problem a while back in which the center pin of the receive side SO-239 socket did not make good/tight electrical contact with the center pin of a standard PL-259 plug.

I fixed the problem by using a 0.5 inch wide piece of aluminum foil... rolled up into a cylinder that was just wide enough to insert into the SO-239 socket’s center pin.

Then I pushed the PL-259 plug into the socket... crushing the aluminum foil insert.

Stu

I might have taken a dental probe (thin point) or a tiny jeweler's screwdriver and gently
urged the springy fingers of the socket toward the center...

                   _-_-

I was restoring a Collins autotune mechanism and the relay contacts were fairly corroded, that is open circuit corroded. I tried every trick there was short of filing/wire brushing the contacts which would be bad news. i finally arrived at a decent solution, 1500 grit wet dry sand paper soaked in DeOxit. Tear the sand paper into long thin strips and fold it over on itself so that you have double sided sand paper strips, soak in DeOxit. Now gently draw the sandpaper between the contacts and watch the contact resistance go back to where it was when new.

I like to use a strip of stiff paper cut to fit between the contacts.  I soak the paper in a bit of alcohol, put the paper strip between the contacts and push the contacts closed while pulling the paper out.  Doing this a few times will usually do the trick.

Well my dow key opened up on me this morning. It was buzzing a while last night and the entire frame was hot during a long transmission where I was just
energizing it with no RF on the coax lines, and there was no voltage on the external contacts. I removed the solenoid section, and on the backplate that pries off it said 115 VAC
so it appears I had the right voltage on it and when I got it there was a AC receptacle attached to the terminals.

Heres what it looks like with the plate off. Another ham said try and rewind it - it reads open. Some fine rust buildup in there on the plunger could have been
the cause perhaps.

Oh and thanks to the people who previously replied , was able to clean the contacts a bit thru that hole after popping off the cover.

I split this topic in two.
The current which you're on now and one that was generate4 back in 2013, http://amfone.net/Amforum/index.php?topic=35237

Topics that are that old (dated November 2013) generally should not be resurrected with current queries or issues but, as I have shown, you can easily provide a link that readers can access and review the old dialog as part of reference.