{Collins} Re: Need Help: 75A-3 PTO Coupling



Jim,
The brass disks with the mating slots/tongues compensate for any offset 
between the axis of the PTO shaft and the axis of the tuning knob 
shaft.  The small spring that you found is probably the one that hooks 
between two roll pins that stick out from the rims of the outer two 
slotted disks, one on the PTO shaft and one on the tuning knob shaft, so 
that the spring spans about 90 degrees around the circumference of the 
three disk sandwich.  This is for the purpose of taking up the backlash 
in the slot/tongue disk assembly.

Bob
WB4TGG

Jim DiMauro wrote:

>Hi All:
>
>I'd appreciate some help with reassembling a 75A-3 PTO dial coupling that
>came apart in shipping.  The radio must have had one heck of a ride, because
>when I unpacked it and opened the lid I noticed that the PTO was completely
>unattached from the chassis and resting on the bottom of the cabinet.  The
>dial mechanism and the PTO both seem to be undamaged, and they turn freely
>and smoothly.  On the surface, it looks like all I have to do is to reattach
>the PTO mounting screws and coupling, make sure the PTO is calibrated with
>the dial, and I should be good to go.
>
>The coupling that connects the dial mechanism to the PTO is apart, and I
>found a heavy brass disc with milled slots that appears to mate with discs
>that are mounted to the dial and PTO shafts.  I also found a small spring
>about 3/4 in. long (including loops at each end) that I don't have a clue as
>to where it belongs.  There doesn't appear to be anything that holds the
>brass disc in place other than pressure from being sandwiched between the
>dial and PTO discs.  Is that right?  I have never seen an assembled 75A-3
>coupling before, so I don't know how it's supposed to look.  Also, how would
>I go about reassembling the thing?  Does the front panel have to come off?
>I need help from square one.  BTW, I have a copy of the user manual on the
>way.  If PTO removal and replacement procedures are covered in the manual,
>then let me know and I'll wait for the book to arrive.
>
>Thanx & 73,
>
>Jim
>WA2MER
>
>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
>
>
>  
>

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






This archive was generated by a fusion of Pipermail (Mailman edition) and MHonArc.