Amberola 1A question - feedscrew/half nut tension

[52089]

I recently swapped out the upper works of my Amberola 1A motor for one that's cosmetically far better than the one I already had. However, I now have a problem in that records skip in a couple of places due to temporary lack of movement of the mandrel carriage. The feedscrew itself looks to be undamaged, so I am assuming that the half nut tension needs a minor adjustment.

Could someone please tell me how best to adjust this? The mechanism is fairly complex and I don't want to mess anything up.

Thanks,
Kevin

[barnettrp21122]

I think this should work for you:
Move the motor stop (front left of bedplate) to the left to keep motor from running.
Put the play (engage) lever down into playing position.
Loosen the two screws holding the mandrel control cover and remove.
I believe the half-nut adjustment is inside, underneath the stop brake drum mechanism. You can see the adjustment screw using a flashlight.

I've tried to take a picture:

A long narrow standard screwdriver should work.
Hope this helps!
Bob

[52089]

Excellent picture Bob, and that's what I was thinking as well, but I'm not sure. I think that screw simply holds the halfnut in position on the bar under the screw. I say that because when I try to move that screw it doesn't want to budge. I was thinking that somewhere above that (i.e. behind the brake drum) is where the tension is adjusted. I could of course be wrong and welcome all suggestions.

[barnettrp21122]

Kevin:
Yes, better to wait for input from someone who's more experienced than I! Hope someone can help!
Bob

[barnettrp21122]

I went back and looked again, and I think I found it:

The arrow shows the tiny screw that appears to adjust the half-nut tension.
It's easy to access too!
Bob

[52089]

I checked my machine and that screw is related to feedscrew tension but doesn't directly control it. The screw you pointed to is actually a set screw for a really tiny screw that sits in the hole below the screw. You appear to be missing that tiny screw.

Theoretically, tightening the tiny screw would move the half nut marginally away from the feedscrew. On mine, there is an air gap between the tiny screw and the carriage, so there's nothing I can do there to tighten the pressure.

The halfnut is mounted on a bar with 2 screws, one of which is the larger screw to the right of the screw you pointed to. Tomorrow when I have more light, I'll try to see if I can remove that assembly and figure out what if anything I can do to adjust this. Worst case I may try to swap parts from the old motor.

Thanks for your efforts so far!

[barnettrp21122]

You're right about correctly identifying the tension and set screws. I went back AGAIN and took another picture. My tension screw is present, fortunately. I would suggest, after loosening the set screw, backing the tension screw OUT (counterclockwise) to bring the half-nut closer to the feedscrew.
I hope this will solve your problem! If not, comparing your other mechanism should provide some clues. Good luck!
Bob

[NEFaurora]

Make sure that you didn't change reproducers either!...and that you are still using the same reproducer as with the 1st motor.

I thought that I would just state the obvious!

)

Tony K.

Edison Collector/Restorer

[52089]

Make sure that you didn't change reproducers either!...and that you are still using the same reproducer as with the 1st motor.

I thought that I would just state the obvious!

)

Tony K.

Edison Collector/Restorer

OK, I'll bite - what difference would changing the reproducer make? It's on a stanchion that doesn't move...

[Jerry B.]

Kevin, Did the serial number of your first mechanism match the serial number on the ID tag? If so, you might want to consider keeping the correct mechanism with its cabinet or at least in reserve. Many big Amberola fans would rather have a lesser mechanism that matches over a better one that doesn't match. If I were looking at two Amberola 1A's and they were identical in every detail EXCEPT one is all matching and the other has a replacement mechanism, I would pay $500 or more for the matching one.
*
A good example are automobiles. Consider the selling price of a matching numbers 1967 big block 427 Corvette in comparison to a 1967 Corvette with a big block 427. The Corvette without the matching motor is worth tens of thousands of dollars less even if the condition is identical. An Amberola 1A is the Corvette of phonographs.
*
I'm interested to know what others think. Jerry B.