REPAIRING SWITCH WAFERS.

A simple repair that is good and cheap

AnThis is a problem that many of us "ham-handed" hams face sometime in our Amateur Radio careers. I had a really nice Drake MN-2700 antenna tuner. It was fine for its purpose and worked flawlessly although it was perhaps forty years old. It looked good and worked good.
And then I did a dumb thing. I was in a fast operating situation and I "hot switched" one of the band switches and out poured the smoke. When I opened it, I found that the wafer on the switch I had abused was on an right-angle drive and three of the contacts were fried.
What to do? First I had a major job of disassembling the thing to get to the wafer but that was accomplished. I held the damaged wafer in my hand and debated what to do to repair this fine tuner. The first thought was to find a replacement wafer. Good luck with that option. The tuner had not been manufactured for many years. The only hope was to find a similar tuner that had been "parted out" and purchase the wafer.


I visited all the auction sites and was disappointed to find that nobody had the part I needed. Without that switch the antenna tuner was worthless. But.....hams never give up! I finally found a wafer in England that was a direct replacement for my fried one. Unfortunately, the ham who had it for sale wanted $90 for it. I don't question his price, anything is worth exactly what someone will pay for it. I was not prepared to pay ninety bucks for it

Back to the drawing board.
As I sat staring at the wafer it occurred to me that I had plenty of switch wafers in the junk box. As I checked them I found that I didn't have one with the appropriate number of contacts in the correct places. However, as I looked at my distressed wafer I saw the contacts were secured by brads. If I could drill them out, I had plenty of contacts on old wafers in my possession so if I could find a way to replace the burned contacts I would be in business. I drilled out the damaged contacts. Then drilled out some from an old wafer. All I need then was a way to secure them. I couldn't brad in the new contacts without the possibility of breaking the ceramic wafer. Not expecting much success I went to an old ACE Hardware store with my wafer. With little conversation the clerk went to an old bin and produced extremely small bolts that were the exact size I needed! I bolted on the new contacts, reassembled the MN-2700 and it worked perfectly. I have since passed it on to another ham and he has it in daily use and my repair job that literally cost me pennies is still going strong.

Repaird Switch

REPAIRING SWITCH WAFERS THE CHEAP WAY

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