LMO Wabble & Lubricant

[John Q. Doe]

In 1978 my SB-303 (built in 1972) developed the infamous wabble problem. The Heath rep relayed the following to me after I whined about the prohibitive cost of the replacment LMO.

The LMO was designed and built by TRW. Their design used a variable cap which was lubricated with a conductive grease. The conductivity characteristic of the grease was obtained with "SILVER FILINGS" added to the lubricant. He gave some detail as to accessing the varaible cap but had no source for the lubricant.

He also told me that the rear bearing of the cap was usually where the lubricant was needed. I failed to ask why the rear of the cap was the significant point vs the front. It may have been that both ends had dried out, but that just lubing one end was adequate to stop the wabble.

It was made clear that the LMO was a dog to service but if one could access the cap then it could be cleaned at the end bearings and relubed.

I did tear mine open and did find it a relatively tough item to service. I used white lithium grease on the end bearings and mixed it with the older grease. The old grease was very stiff but since I did not have any "SILVER IMPREGNATED" lubricant I opted to try to blend the old with the new. That served me well until about 3 years ago when the LMO started the wabble again.

He was very adamant about the lube having silver and not some other conductive element.

Hope this helps

Chuck WD4HXG

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