[Subscribe to Daily Digest] |
Members do not see ads below this line. - Help Keep This Site Online - Signup
A very old gent asked me to fix his very old record player. The turntable platter would not. The turntable patter bushing type bearing was siezed. It took a lot of very serious hammer blows to drive the shaft of the mechanism out of the turntable's sleeve bearing. The grease had hardened like epoxy. I got that cleaned up then turned my attention to a geared cam wheel that is part of the auto changer. It was the same. When it was turned, the shaft that is riveted into the mechanism base turned there, the sleeve bearing of the gear was again stuck with hardened grease, so much so that the rivet joint turned instead. The turntable platter was mostly plastic, but this was all metal. So was able to I the heat gun on it for a while and got it hot, then I was able to slide it off its axle. The hardened grease melted quite nicely
The same grease everywhere else in the mechnanism was as new after 35 years. Why just these two locations? In both cases, there was a ground hardend steel shaft and a zinc die cast tight tolerance bore. So the zinc alloy, or it in combination with the steel, caused the grease to turn to a very strong solid. So this is an example of what appears to be a metal catalyzation of grease/oil to a solid, but at room temperature. I have read where it was stated that wear metals act as a calalyst for oxidation of engine oil. So todays observations played into that quite nicely.
The turntable now has synthetic grease and Mobil Delvac 1 5W40 oil. I don't think anyone will be interested in how that fairs in 35 years.
So the whole exercise took hours. Ganged volume pot needed to be removed and taken to bits to be cleaned up, soldered back in. Grabbed a vinyl LP of Micheal Jackson's 'Thriller' for testing (his collection not mine).
Too much time on my hands.
posted by 66.142.222...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
