[Hammarlund] SP-600 dial slippage

Sat, 15 Jun 2002 18:52:31 EDT

In a message dated 6/15/02 5:38:03 PM, [email protected] writes:

<< 1.Carefully clean the edge of the dial,the friction wheel(the small one) 
and

the flywheel..You will be suprised the junk that is on the surfaces..I used

isoprophyl alchohol some cotton and a tooth pick.

If slippage persists more drastic measures are necessary.Next remove the

front panel a bit of of a job.Put the radio on its back.The side panels rear

extensions will clear the fuse cover etc on the back apron.Next remove the

brass trapezoidal section that holds the bandswitching mechanism shaft.Next

remove the vertical metal section that has the band dial attached..You now

have access to the dial drive mechanism..You will see that the small

friction wheel is seated in a three point bearing that "floats" under

tension of the hairspring..Make sure the spring is intact and properly

seated in the small holes Carefully move the flywheel a bit..You will need

to hold the flywheel since it is not supported without the previously

removed sections..Don't move the dial too much..The anti-lbackash gear on

top of the gear train is now unsupported and moving it too much can damage

the main dial gear train...At this stage you can further disassemble the

gear train to clean and lubricate the bearings but DON"T LUBRICATE the gears

themselves...This is not a job for the fainthearted but well worth it..I

have some pictures for those who are interested...Lou ND6W

 >>

Lou,

This is "EXACTLY" what should be done. I have cautioned against lubricating 
the gear train for years. But that is usually the cause of 90% of the 
slippage problems. The oild from the gears ends up on the friction drive 
pulley and the dial edge.

One item, freon as used in cleaning tape heads on tape recorders works much 
better than alcohol. removes oils completely.

I've had 19 of these fine receivers and have never failed to fix this problem 
with your advice.

Les Locklear
SP-600 Historian
http://www.hammarlund.info/
Gulfport, Ms.