Grunert Refigeration problem

[onehalfmoon]

Hi

I have an OLD Grunert refrig / freezer setup. Techcumseh CE compressor, dual solenoids for Frig / Freezer, 1/2 hp 12v Dc motor and running R12,

The unit has worked flawlessly for years, fulltime liveaboard.

Recently the system has developed a chattering noise. As a guess I would say that the noise is at 1-3 Hz. It will make the noise upon start-up and then gradually diminish. With the Refig. side off and the Freezer side operating it is particularly bad and will continue though the whole cycle.

Initially I though a rattling tube but have gone though it multiple times and no amount of pushing / pulling on the tubes changes the noise???

Any suggestions..

Thanks

[DeepFrz]

Perhaps the motor needs new brushes? Maybe you need a new fridge? Compressor?