[Hallicrafters] SX-88 Gear Train Rebuild

[WA1KBQ at aol.com]

In a message dated 9/18/2007 3:40:52 P.M.  Atlantic Standard Time, 
roy.morgan at nist.gov writes:
Has anyone dis-assembled  an SX-88 gear train?

I have one to do and wonder what tricks there are to  put the anti backlash 
into the split gears and keep it there during  re-assembly.
I have done a couple. It's the only way to clean and properly  lubricate the 
bearings but they are a little tricky to get back together. When  you have it 
apart be sure to look at all the bearing balls with a magnifying  glass to see 
if any are flat spotted. The last one I did had this condition and  needed 
them replaced. I was able to locate the correct size replacement bearing  balls 
at McMaster Carr Industrial supply in Atlanta available in a box of 100.  The 
main consideration for the SX-88 geartrain is the reduction gears have to be  
timed so the end stop cams engage the followers at the precise time. This will 
 involve some trial and error (meaning disassembly and reassembly) as you try 
 different gear tooth engagement positions to get them timed properly on both 
MT  and BS. It was easier for me to leave the springs out for this step and 
put them  in after I had it right. Find a suitable pick to push them in place 
but be  careful to have a means of containing them as they will quickly get 
away, fly  across the room and ruin your day trying to find the little wayward 
spring  again. These springs are not like any used in other common receivers so  
replacements would need to come from another SX-88. Also, be careful of the  
preload on the shaft end bearings, just enough to adjust to zero end play. 
When  the SX-88 reduction geartrain is clean and adjusted properly and sparingly  
lubricated in the right places there are none finer when you give that silky  
smooth flywheel weighted knob a spin down the band.

73, Greg  




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