{Collins} Re: Preselector slipping on 75S-1



Ken, WA2LBI wrote:
> Thanks to All for the numerous responses and good advice! 
> 
> Late last night, prior to receiving all of this great information, I took a 
> good look at the rear bearing. I have a set of Bristol spline keys so I 
> removed the locking nut and bearing adjuster.  I noticed the ball bearing 
> embedded in dried grease so I removed it with a magnet, cleaned everything, 
> relubed it with white lithium grease, and reassembled. I also added a dab to 
> the vertical slides. I was careful not to disturb those flimsy metal foil 
> bands. After adjustment the preselector now works smoothly and reliable 
> through its entire range. 
> 
> Thanks to those who warned about disassembling the tuning rack. I work on 
> Drake gear so I know better than to disassemble a tuning rack! I also know 
> not to use grease on plastic parts, especially the dials and gears. DeoxIT 
> has been used only on the switch contacts, not on the wafers (they soak up 
> the fluid and expand). A variac and light bulb fixture is used to power up 
> all rigs brought into my shop. I know about loosening/retightening chassis 
> screws to eliminate a number of problems. 
> 
> The PTO is next. It isn't as smooth as it should be. 
> 
> Thanks, 
> 
> Ken, WA2LBI 
> Sponsored by the Collins Collectors Association http://www.collinsradio.org
> Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
> Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
> 1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
> Sun AM Net: 29.050 Mc-1200 Central
-----------------------------------------------------------
Ken,

Glad to hear that you fixed that slug rack.  Yes, that single ball 
bearing at the rear of the slug rack is the friction adjustment, as you 
found out.  Some of those balls were metal and some were nylon.  In any 
case, tighten the friction just enough to let the Preselector work from 
end to end.  Sounds like your Drake experience has helped you here!

Don't forget that world renown Collins expert Dennis Brothers, WA0CBK, 
shows you, step by step, how to take the 70K-2 PTO apart (in the radio 
and out) in his "Collins KWM-2 Video".  He shows you exactly how to shim 
the shaft for dial drag and he also shows you how to remove the lead 
screw, clean the old grease out of it, relube with white lithium grease, 
and reassemble.  All the PTOs were the same in the S/Line and KWM-2s, so 
that procedure would be the same for your rig.

Good luck and have fun with your Collins radios!
-- 
73,
Floyd Soo, W8RO
President, HI-RES Communications, Inc.
President, Collins Collectors Association (member #2)
floyd@xxxxxxxxxxxxx


Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
Sun AM Net: 29.050 Mc-1200 Central





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