Re: Clean and Lubricate Pots in Tek 475


 

Jeff:
Don't be mislead slightly by the removal of the 465 vertical preamp board in the eevblog tear down. The 475 vertical board differs in that the attenuator switches and BNC front panel connectors do NOT come out with the vertical board. The vertical board is separated from the attenuators by unsoldering the connection between the attenuators and the vertical board. There is a difference in what components are involved here depending upon S/N. This makes the removal a little easier than in the 465. Follow the instructions in the manual section on Vertical Preamp Circuit Board Removal. Make sure you have the correct manual for your S/N. Both of mine are S/N 250000 and up. Also be careful when removing the Delay Line connection to the vertical board as there is a solder connection here. I guess I should have photographed and documented my removal of the vertical preamp board in the 475. My bad! Some day Real Soon Now.
I have always used the Caig Laboratories line of contact cleaners and contact restorers. Cramolin and then the Deoxid line of contact cleaners. I have used the WD40 Cleaner for some applications. The WD40 brand seems to have a line of different products now. I have seen one other reference to using the original WD40, used for loosening corroded bolts, for contact cleaning/restoring. This was in a GR 1432 instruction manual dated 1956. I was surprised to see this and didn't understand exactly why. But I guess GR had some reasons for doing this. I don't think that TEK intended for WD40 to be used on the pots, nor did they expect the pots to need cleaning. But 50 years does take it toll. I am not as good 50 years later either at the ripe old age of 80.
Bill

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