[Heathkit] [Heath] Lubing / Unsticking' the SB-401 LMO

[Glen Zook via Heathkit]

I haven't written up this fix like I did for the elimination of "warble" for the LMO.

What I used to clamp the "pinch" drive halves together was a pair of wooden spring type clothespins.  Then, I applied some soldering paste to the shaft where the solder was to be placed.  Next, put the "other end" of the shaft into a vise.  Finally, I used a 100/140-watt Weller soldering iron and "normal" 60-40 rosin core solder.

I don't have a high wattage soldering iron so I had to use a soldering gun.
 
Glen, K9STH


Website:  http://k9sth.com


On Monday, July 28, 2014 10:10 AM, Chris Kepus <ckepus at comcast.net> wrote:
 


Glen,
Any chance you saved some photos or narrative of your work in that area, especially “soldering the end of the shaft”.  If you don’t already have it written up, it sounds like all of would benefit from some pics and/or specifics, like, what did you use to successfully clamp the two halves of the “pinch” mechanism… and, which of your soldering weapons did you apply to the shaft?  
Thanks,
Chris
W7JPG
 
From:Heath [mailto:heath-bounces at puck.nether.net] On Behalf Of Glen Zook via Heath
Sent: Sunday, July 27, 2014 8:31 PM
To: RAY FRIESS; Robert Myers; heathkit at yahoogroups.com; heathkit at mailman.qth.net; heath at puck.nether.net
Subject: Re: [Heath] [Heathkit] Lubing / Unsticking' the SB-401 LMO
 
As for adjusting the "pinch" drive, after one has done several, it does get easier.  However, as for tightening the "pinch" mechanism itself, that is definitely harder to accomplish.
 
I have found that soldering the end of the shaft, while clamping the two halves of the "pinch" mechanism, usually gets it tightened up for a couple more decades.  Of course, one has to confine the solder to just the immediate area near the shaft.
 
Glen, K9STH
 
Website: http://k9sth.com
 
On Sunday, July 27, 2014 9:13 PM, RAY FRIESS <rayfrijr at msn.com> wrote:
 
My biggest gripe and grief with the SB line of dials is the dual copper disc pressure system Heath engineers
dreamed up.  You can almost always count on some day the discs either breaking from the shaft or loosening up
so the dial turning gets erratic or stops altogether.  The engineers had a great dial mechanism on the single band
units.  I don't know why they couldnt have designed the SB units using the same type of thing.
Disassembling and reassembling the drive units in the SB line has probably driven many a ham to drink, trying to
get the dial in between those two discs and getting the correct upward and downward pressure at the right location
and then tightening the nut without the shaft slipping out of place.  I have uttered many a scream, added new flavor
to many age old cuss words and probably even invented a few new ones while working on the SB drive mechanism.  HI HI


> From: rsmyers at rogers.com
> To: heathkit at yahoogroups.com; heathkit at mailman.qth.net; heath at puck.nether.net
> Date: Sun, 27 Jul 2014 19:12:58 -0400
> CC: rsmyers at rogers.com
> Subject: [Heathkit] Lubing / Unsticking' the SB-401 LMO
> 
> Thanks to everyone for advice on 'unsticking' the SB-401 LMO that locks at
> 4-1/4 revolutions (as shown on the turns counter dial).
> 
> A couple follow up questions:  
> 
> 1. What grease cutters or cleaners do people recommend for removing the
> dried, or thick, original lubricant. 
> 
> 2.  What do people recommend for lubricating the system after step 1 (and do
> you need to use conductive grease anywhere in there)?
> 
> Thanks,
> --- Rob Myers, VE3JQL
> 
> 
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