[TenTec] Replacing Centurion Amplifier Interlock Switch

[Michael Rutkaus]

It is easy to break the interlock switch by putting the cover back on from the back. Always spread the cover slightly and put it on straight down from the TOP.

 

After investing in two sets of high grade offset screwdrivers (and cutting down one Phillips bit), I was able to replace the 422 interlock switch without moving the transformer; I took off the 3 most accessible circuit board screws, loosened by ¼” the most distant one, loosened the transformer screw connections from the board, and lifted the board up in the area of the switch. There was room for detailed careful work

 

I epoxied 2 blind 2-56 nuts to the bottom of the board to mount the new switch, thus making it easily removable when everything is put together. 

 

Also I made 2 new, doubled up flexible  longer solder connection insulated wires to the switch from the board so that, once the switch is removed next time there is room to unsolder it and solder in a new one without the heat loosening the wire connection to the circuit board.

 

I used 2-56 hex-head cap screws to mount the new switch, and 4-40 hex head cap screws for 2 of the circuit board screws to make it easier to use Allen wrenches should they need to be removed.

 

I ended up using a slightly different OMRON switch than the original  as you can see in the picture, almost the same part number but with shorter and narrower terminals with holes in them to allow for the new leads. The original switch could be used by clipping the NC contact off and shortening the two other contacts. 

 

Mike

K4QET