07-20-2012, 11:40 AM
I am working on a model 600 and removed the pot/switch to fix the switch part which was on all the time. I successfully de-greased, cleaned and lubed the switch part which works fine now but discovered that the pot section has a bad carbon section near the 7 o'clock position.
The resistance reads 35K from end to end (should be 15K) and as the wiper is moved from CW to CCW and reading from CW to wiper the resistance goes down monotonically until I reach the 9 o'clock position from where it increases again. Upon close inspection it appears that the carbon is cratered and worn from the 9 to 7 o'clock position probably since the control was operated in that area most of its life.
I know pencil led can be used as a resistive element and I would like to perhaps make a paste from some type of glue or paint and pencil lead which I can fill the pitted areas with and establish continuity. Does anyone have any ideas or experience doing something like this.
BTW this control is connected at the antenna input which is why the value is so low.
Thanks,
Steve D
The resistance reads 35K from end to end (should be 15K) and as the wiper is moved from CW to CCW and reading from CW to wiper the resistance goes down monotonically until I reach the 9 o'clock position from where it increases again. Upon close inspection it appears that the carbon is cratered and worn from the 9 to 7 o'clock position probably since the control was operated in that area most of its life.
I know pencil led can be used as a resistive element and I would like to perhaps make a paste from some type of glue or paint and pencil lead which I can fill the pitted areas with and establish continuity. Does anyone have any ideas or experience doing something like this.
BTW this control is connected at the antenna input which is why the value is so low.
Thanks,
Steve D
