[Heathkit] SB-630 Clock

[Drew P.]

Gary wrote:

> I know this is not a new subject but did anyone ever
> identify a replacement
> for the clock motor used in the SB-630?  I believe it
> has to be 1 RPM to
> keep the clock accurate.  I have tried the drilling
> holes on the top and
> adding oil routine, but that has not been successful.

I have encountered electric clocks with "Telechron" and similar synchronous motors which had become noisy and kept poor time due to wear in the motor's bushings.  I have sometimes been successful at restoring quiet, accurate operation to these by applying a drop of relatively heavy oil (SAE 30) to the motor bushing surfaces.  A synthetic oil would be best, not for any imagined superior lubrication qualities, but because synthetics take much longer to gum up than do conventional oils.  The clock in a Hammarlund HQ-series receiver responded well to this treatment. The speedometer in my automobile would on cold mornings squeal loudly and the needle would peg at slow speed, even though the speedometer cable was well lubricated. The entry bushing in the speedometer head had excessive play due to wear; heavy oil applied there corrected the problem.  Evidently the oil's viscosity damps out vibration otherwise induced by the rotating part rattling around in the
 worn bushing, be it in a clock, speedo head, or wagon wheel.

Drew