Collins 51J/R-388 band change drum/pulley question:
 

Has anyone ever fooled around with the band change drum/pulleys with the
Collins 51J/R-388 series of receivers? It seems I've acquired a 51J-2 that the
band is way off. Unfortunately, I do have a manwell, but have been able to
figure out a few things by myself.

The way it's working now, I have applied spring tension on the band drum. It'll
go 180 degrees one way, then do an about face and go 180 degrees the other way.
It seems the way I received it, the pressure spring came loose and was riding
on the graticule!

Any information on how I can correctly align it will be greatly appreciated.

Regards,
Joe Cro N3IBX

I do have a manwell,

yes, meester fawlty? Que?

JOE wrote:

I do have a manwell,


yes, meester fawlty? Que?


"I do have a manwell, but have been able to
figure out a few things by myself."

MILAGRO!

Spling duznt count when it comes to knowing about how to best hack up
old radios.
"Yep, me glurst hap ya end with prefect reception but yap me blist fer
the smell".
Dope...we gotta control it.

-ex

The main thing with this scheme is the initial starting position of the dial
drum assembly. This gives you the reserve so you don't "run out of dial/drum
string" when actuating the band change mechanism. It's been several years
since I've done one of these receivers, but it shouldn't be too hard to
figure out, at least without a few tries. I don't know if the BAMA website
would have this information; the technical manual of this receiver is quite
a few pages.

Pete

"Yardleyite" wrote in message
...
Has anyone ever fooled around with the band change drum/pulleys with the
Collins 51J/R-388 series of receivers? It seems I've acquired a 51J-2 that
the
band is way off. Unfortunately, I do have a manwell, but have been able to
figure out a few things by myself.

The way it's working now, I have applied spring tension on the band drum.
It'll
go 180 degrees one way, then do an about face and go 180 degrees the other
way.
It seems the way I received it, the pressure spring came loose and was
riding
on the graticule!

Any information on how I can correctly align it will be greatly
appreciated.

Regards,
Joe Cro N3IBX

Try this method, paraphrased from page 84 of the R-388 tech manual TM
11-854:
- Detach the drum cable from the drum pulley, but keep tension on it so
it doesn't slip off the bandswitch pulley which is down behind the front
panel.
- Set the band switch to the highest band (29.5 to 30.5 Mc)
- Turn the drum (and hence the drum pulley) about half a turn and hold
it against the tension of the spring.
- Run the cable up to the drum pulley (its front edge, closest to the
front panel of the receiver) and work it around the pulley one and a
half turns or more as required, before attaching the end to the drum
pulley. Now the drum should have the correct tension.
- Loosen the setscrew in the hub at the opposite end of the drum. This
requires one of those small Bristol wrenches. Align the drum so the
29.5-30.5 Mc scale shows through the window. Tighten the setscrew.

It might be good to have a helper hold the drum tension while you wind
the cable around the drum pulley.

FYI, TM 11-854 can be downloaded free of charge from
http://www.kg7bz.com/Manuals.html (thanks to August Johnson, KG7BZ).

73 & GL,
Joe K9LY


In article ,
(Yardleyite) wrote:

Has anyone ever fooled around with the band change drum/pulleys with the
Collins 51J/R-388 series of receivers? It seems I've acquired a 51J-2 that
the band is way off.