Ristaucrat Rebuild

 




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How to rebuild the Ristaucrat record changer

Ristaucrat record changers are the same mechanism in the Ristaucrat 45, the Ristaucrat Dial-O-Matic and most of the same sub-assemblies as in the Ristaucrat S45 Selective.

Ristaucrat Record ChangerIn August 1949, brothers Arnold E. and Alfred G.  Ristau of Ristaucrat Inc. located in Kaukauna,  Wisconsin secured a "record changer" patent for the then new RCA Victor 45 format. The most important feature is the invention of a mechanism for raising a group of played records up the spindle to the support shelf/knives so that stack of records can be continuously played and restacked.



Spindle Cap

 

1. Remove two screws from spindle cap, be careful the cap is spring-loaded.




Spindle Cap Off

2. Lift the spindle cap and notice the two springs that sit on the flat half-dollar-size washer that has four holes, two of which align the two springs with the two spindle cap screws.



Oscillating knives and record shelves

3.Gently lift the two retractable knives and two supporting fingers that hold the stack of records from inside the spindle; notice the compression spring that pushes both fingers outward.



Oscillating pinions

4. This assembly is only three pieces. Check the gears on the two oscillating pinions for any broken teeth. The spring should be fine.



Oscillating shaft

5.  This oscillating shaft has a gear that has been swaged or later ball-peened to secure it to the shaft. Check that this gear is perpendicular to the shaft. If not or if itís loose, gently ball peen it.



12 tooth segmental gear



6.  Loosen the two screws that hold the 12 tooth segmental gear. Note: earlier generation machines have only one screw.



12 tooth segmental gear

7.  A common problem is this unusual gear will have loosened and fallen off the oscillating shaft. Look under any packing material for loose parts. As I didnít know of any source for this gear, I had a couple of replacement gears made at a local machine shop.



pot metal friction clamp8. Loosen the screw that compresses the clamp which is secured to the underside of the mounting plate. This clamp holds the rotatable fixed tube into which the oscillating shaft is placed.

You might have to gently pry open the pot metal clamp that holds the fixed tube "centering post". Ristaucratís pot metal is better quality than used in earlier generation phonographs.  Pry as little as possible and very gently so the clamp doesn't permanently loosen or crack.



pot metal friction clamp drawing9. Good friend RepairTech on the Antique Radio Forum gave me permission to use his nice graphic image of a common troublesome pot metal clamp. Loosen the screw, only gently pry it open if you can't pull the shaft out of this clamp.

If the pot metal clamp wonít tighten and the centering post shaft still rotatesĻ after you tighten the screw, you may have to file the end edge of inside of the clampís grip. Ļ Unlike the RCA RP168 and RP190, the spindle and stack of records on Ristaucrat changers do not spin with the turntable.  So if a stack of records jams, owners will often attempt to release the jam by rotating the spindle counter-clockwise (correct for the RCA RP), wrong for Ristaucrats, doing so will cause this common problem. 



spindle pole and half gear

10. Remove the spindle pole and 12 tooth half-gear. Check for broken teeth.



Underside of turntable

11. Gently but firmly lift the turntable; notice the two washers and thrust ball bearing.

In this photo the other washer is stuck to the bottom of the bed plate as seen in photo 14.

 
turntable centering guid

12.  Firmly pull and if necessary twist (as if unscrewing) the turntable centering and guiding column out of the spindle. If itís frozen in place, gently tap the base of the column to loosen it.



Idler wheel on bed plate

13.  You can now see the idler wheel. Itís easy to remove by simply loosening the screw in the center.

For best long-life, quiet and good gripping performance, (to pull like a truck) I recommend replacing or grinding the idler if you're not sure of its age or if any evidence of slipping and not gripping. More likely the rubber will have hardened or lost its shape over the years after having been pulled against the inside rim of the turntable, and/or motor's axel; see photo in step 15.


If you grind the edge of the idler such that the radius and thus circumference of the larger tire is now smaller, you need to replace or enlarge the smaller tire to achieve 45 rpm.



idler wheel, screw, two washers, nut




14. Be sure to hold the nut and washer underneath the bed plate while you lift the idler wheel out.



idler pivot arm

15. Thoroughly clean and lightly oil the spring-tensioned pivot arm that holds the idler wheel. This pivot arm should spring back and forward easily to pull and back-off the idler against the inside rim of the turntable.


More to follow....

 



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