Batboard

Ok so I sprayed some contact cleaner in the squelch pot of an MSF station I have that is running with a zetron controller. As you know when you connect a zetron to these the squelch function on the pot controls the zetron's carrier light, and recently I felt the pot was sticky because the zetron would transmit squlech noise through from the open squelch condition. After waiting 20 minutes for it to dry I turned on the repeater and although the repeater came up and the zetron showed it had power nothing would happen. No transmit no receive, nada!

I am wondering if the station control board is screwed up now or maybe the squelch pot has shorted out? I Have yet to bypass the zetron and use the MSF's built in controller as I would have to lug the 386 to the site and reprogram the repeater. I can manually force the repeater to transmit by holding the TX button of course but no COR activity shows up on the zetron, etc.

I haven't attached the meter panel to it yet to see if the receiver is dead for some reason now...


Any ideas guys?

P.S.- I knew I should have used the "No Flash" spray instead of regular contact cleaner spray!

Cleaning the pot with contact cleaner shouldn't have caused it to stop working.

I've seen plenty of squelch and volume pots that were extremely noisy and also terribly loose. If something pushes against the front of the station, it hits those knobs first and they push the pot enough so the metal body begins to separate from the phenolic resistive element. You then end up with an intermittent pot and at worst, it doesn't work at all.

The easiest thing to do is pull the control board, unsolder the pots, squeeze the back and front together, and re-crimp the four tabs that hold the back cover of the pot to the front so everything is mechanically tight. While it's out, you can squirt some contact cleaner directly into it, twirl the shaft a few times, and then check that it's working properly using an ohm-meter. Reinstallation is simple.

After the pots get destroyed due to pressure against the front of the station, the toggle switches are usually the next casualty. Motorola used to use long handles on them that stuck out over half an inch. Those were the most susceptible to damage. They eventually went to 1/4 inch handles that are harder to use but harder to damage.

Bob M.