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Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 12:03 am
by pianolist
After replacing a broken main spring and servicing the motor, my Actuelle model H plays well. I examined the arm and needle suspension and don't see anything that would wear or fail that would require rebuilding as one would with a standard reproducer. Am I missing something or is there nothing one must do to the arm and stylus assembly?

Thanks!

Ron

Re: Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 8:07 am
by CarlosV
I never touched the tone arm of my machine. It connects needle to cone via a long bar inside the arm tube, and as everything looked well tightened and the sound was good, I left it alone. As far as I can tell there are no gaskets or other wear-prone components. There may be a gasket fixing the paper cone to its metal frame (I never disassembled it), but if there is one it is probably cardboard or felt with no need for replacements.

Re: Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 10:13 am
by VictrolaGuy - Walt
Referring to the five (5) pictures below, there are three (3) compression springs that you will want to pay attention to. Whether they need to be adjusted is something you will have to empirically determine. The first two are the balance springs (picture 1 and picture 5) and are visible without disassembly (picture 1). The third spring is not visible without disassembly (see pictures 2 and 3), but it controls the tension necessary to allow proper orientation of the stylus/chuck. (Yes, the chuck can be rotated. In fact, you cannot remove the balance springs unless you rotate it.)

An example of the most common problem I see with the Actuelle H is shown in the detailed view of picture #5. I include the picture because I often see this. Note that one of the compression springs is broken. Note also in picture 1 that this is not immediately obvious, but it will cause distortion during reproduction due to resonation. These springs are just a few turns and are fairly rigid. My opinion is that the springs were not properly heat treated and ultimately wound up being too brittle. Under tension brittle springs crack.

The rotation of the stylus (chuck) is very important so that the shaft of the ball sapphire is properly oriented. I have never seen a problem with the tension spring associated with the needle chuck. (NOTE: The final adjustment/rotation of the stylus chuck should be completed before you tighten the nut at the cone (not shown)).

Assuming that the diaphragm itself is good you might want to verify that the hollow brass tube extending from the stylus chuck to the center of the cone is not damaged or touching the inner wall of the support arm. Make sure the solder connections of the tube ends (i.e. at the crimp near the needle chuck and near the inner cone washer) are good. I have seen corrosion of the solder joints but nothing detrimental to proper operation. A little alcohol and a cotton swab will clean that up easily.

Check the stylus fulcrum points (picture 4) for rust/damage. They should both have a well defined knife edge, each being the same relative height as the other.

In my experience the balance springs are typically much too tight. You need only loosen them an 1/8th of a turn or so. Assuming they are balanced to begin with you will want to make sure that you adjust BOTH of them by the same amount. Pathé recordings are, in my opinion, worthy of your attention to the balance spring adjustment.

There are no gaskets or rubber isolators of any kind in this design. There are a few patents that cover the design but they tend to be a bit too conceptual and not literal enough to help with the actual (pun intended) service.

Re: Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 2:52 pm
by CarlosV
That's very clear and didactic, Walt, thanks for posting it! That encourages me to do at least an external visual inspection on the springs and fulcrum edges.

Re: Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 3:29 pm
by VictrolaGuy - Walt
CarlosV wrote:...That encourages me to do at least an external visual inspection on the springs and fulcrum edges.
A very fine diamond file or even a fine fingernail file/emory board will work wonders on those edges.

Re: Pathé Actuelle needle suspension rebuilding?

Posted: Sat Nov 11, 2017 10:45 pm
by pianolist
Thank you. I will check all those points.

Ron