R209 MkII/B wafer switch S2C S2D advice - UK Vintage Radio Repair and Restoration Discussion Forum

G4_Pete · 5th Jul 2019, 7:33 pm

Hi, Ref photo it looks like the contact on S2 C/D fouled one of the contacts and bent it out of shape, the rotating contact is also badly warped so that it misses the other contacts instead sliding between the contact pairs.

I am not sure how to tackle this as the wafer is embedded in the RF enclosure. I have not attempted anything yet but was wondering if the shaft could be withdrawn to allow the wafer to be withdrawn but even then wires on the bottom look inaccessible to a soldering iron.

Any Ideas.

Pete

Ed_Dinning · 5th Jul 2019, 7:43 pm

Hi Pete, looks like a case for some micro surgery.
If all else fails I may be able to find you a suitable wafer, but the replacement job is equally horrendous.

Ed

G4_Pete · 6th Jul 2019, 9:50 pm

Hi Ed,
I managed to recover the switch using a combination of small de-soldering hooked tools and prods and some wooden ice lolly sticks and a magnifying glass. The thing that made the whole job possible was disconnecting the indexing cog so the wafers could be rotated gently back and forth to check for correct operation and no catching. Before I removed the indexing cog I crunched up the switch again due to the force required to change bands completely masking the mechanical fouling.
This was my key learning from this repair.

Pete

5th Jul 2019, 7:33 pm	#1
G4_Pete Hexode Join Date: Feb 2014 Location: Southampton, Hampshire, UK. Posts: 419	R209 MkII/B wafer switch S2C S2D advice Hi, Ref photo it looks like the contact on S2 C/D fouled one of the contacts and bent it out of shape, the rotating contact is also badly warped so that it misses the other contacts instead sliding between the contact pairs. I am not sure how to tackle this as the wafer is embedded in the RF enclosure. I have not attempted anything yet but was wondering if the shaft could be withdrawn to allow the wafer to be withdrawn but even then wires on the bottom look inaccessible to a soldering iron. Any Ideas. Pete Attached Thumbnails

5th Jul 2019, 7:43 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: R209 MkII/B wafer switch S2C S2D advice Hi Pete, looks like a case for some micro surgery. If all else fails I may be able to find you a suitable wafer, but the replacement job is equally horrendous. Ed

6th Jul 2019, 9:50 pm	#3
G4_Pete Hexode Join Date: Feb 2014 Location: Southampton, Hampshire, UK. Posts: 419	Re: R209 MkII/B wafer switch S2C S2D advice Hi Ed, I managed to recover the switch using a combination of small de-soldering hooked tools and prods and some wooden ice lolly sticks and a magnifying glass. The thing that made the whole job possible was disconnecting the indexing cog so the wafers could be rotated gently back and forth to check for correct operation and no catching. Before I removed the indexing cog I crunched up the switch again due to the force required to change bands completely masking the mechanical fouling. This was my key learning from this repair. Pete