Repair guide for a Berkshire

[Timothy Murphy]

    A friend has asked for my help to adjust the clutch on the Collins auto-tune on his Berkshire. The motor and gear train want to turn, but the clutch slips before they can start.

    Does anyone know of something like a Chilton's guide for this servicing? This involves heavily layered mechanical assemblies, the radio equivalent of an automatic transmission, so pictures and how-to short cuts would really be the way to go. Thanks,

Tim Murphy

[Norman S Braithwaite]

Tim:

I have the RCA service data for the Collins Autotune.  It includes an exploded parts diagram and other information.  If interested I can scan and e-mail the service information for the Autotune but I will not be able to get to it until next week.  If you are planning to attend the CHRS August quarterly swap at Foothill College on August 4th, let me know and I will bring photocopies.

Norman

[Timothy Murphy]

Norman:

  Thank you. I knew that you would have these materials! But I will not unfortunately be in the area on August 4th. I also have the data that I think you mean.

  As you know, the exploded view of the Autotuner folds out across several pages. That is what brought to mind the reference to an automatic transmission. Comparison of the physical unit to the diagram, is very difficult. Isn't there some kind of a picture book to help not-so-smart guys fiddle their way through these units?

  Plus, you have to extensively dismantle the radio to get to it - I mean, dozens of parts and subassemblies. There must be shortcuts.

Tim Murphy

[Norman S Braithwaite]

Tim:

Other than the RCA service data I am unaware of any repair guides for the Autotune.  I am sure that there are some military manuals that address the Autotune but I expect that there are some differences between the military units and those that RCA used.  Without need and without success, I have expended some effort to figure out how the Autotune works.  I even have a machined demonstrator unit with glass sides which provides little help in understanding how it works.

Norman

[Timothy Murphy]

Norman:

  Wow! Very cool. I've determined that it's magic. Has something to do with those little locking tabs.

  But seriously, some aircraft mechanics someplace knew how to dial these things in. And the post-war military aircraft manuals are enormous and detailed. There must be somebody who can identify a "how to" picture book on it. Maybe I should contact Planes of Fame at Chino?

Tim Murphy

[Angelo]

Do a search on Collins R-391  manual  it has autotune on it ..Try searching for   TM11-863 thats the instruction book for R-391/URR ..It will have everything on its autotune.Sprman

[Timothy Murphy]

Angelo:

   Genius. I'm on it. Looks like the 300 page hardcopy goes for about $30. Thank you so much. This will just fit the nightstand.

Tim Murphy

[Angelo]

Timothy i have a R391  ,lol true heavy wieght radio ..I got my manual free off web PDF download search that.Its very clear and shows everything they are  very hard to adjust ect.I have never done it myself.Good luck with it.They do tell how to clean everything ect.Angelo

[Timothy Murphy]

Angelo:

  Wasn't it Hannibal who said, "It can't be that hard"? Watch this space. (It may be awhile.)

Tim Murphy

[Angelo]

There is a Collins Collectors web site.Collins Autotunes they each may be diffrent.They used them on both ground based and airborne Equipment...Good Luck.Angelo