Band Switch Cleaning

[N8CMQ]

Hi All!

I have read several comments about band switch cleaning where the contact cleaner
has caused problems with the switch wafers absorbing the cleaner and becoming
intermittent.

I have has success cleaning the wafers with 99% isopropyl alcohol to dry out the cleaner.
Use a small spray bottle with a pump top to apply the alcohol and let it drip onto a rag to
absorb the excess alcohol.

If the switch is still intermittent after cleaning, then the contacts may be worn and need
adjusting. I like to use dental tools to adjust the contacts. By watching the wiper enter the
contact, you can see if the contact spreads when the wiper enters the contact. If it doesn't,
then it needs adjustment.

If the plating is worn off the wiper, chances are, the contacts are worn too. They will still
work, but they will need tweaking of the contacts to get good wiping action to help keep
them clean with use. A good lube should also be applied to keep wear to a minimum.
There are several greases sold for this use, I use a silicone based grease for this use.

After all this work, if the switch is still intermittent, and you have soldered the rivets and
all the other little tricks, check the wiper position when you go through the positions. If
the wiper does not stay centered, check the wafer opening for the actuator shaft for wear.
You may need to shim and glue the opening to tighten it back up.

Good luck and keep up the restorations!

[WA2SQQ]

When I rebuilt my Hammarlund HQ-180 I used Deoxit on the wafer switches. What I noticed was that the phoenelic material absorbed the Deoxit and actually swelled up a bit. The switch operated much tighter for quite a while. When those contacts do wear, and loose tension, I'm wondering how you can retension them? Can't really bend them as there isn't any space to bend them down.

[N8CMQ]

I have used dental probes to bend and retention the contacts of wafer switches.

The swelling of the switch decks can be reduced by using the isopropyl alcohol.

[wa4nlw]

Can you recommend a few specific lubes for the switch?   My swan manual tuner needs some attention badly


Tks 73 WA4NLW Matt

[Jim, W5JO]

De-Ox-Id