Fixing a Cracked Tonearm

[lloprete]

Hello!

I'm new to the hobby and have a quick question regarding restorations. I was recently given a Silvertone portable phonograph. I don't know the name of the model, but it is identical to this one:
http://www.ebay.com/itm/ANTIQUE-PORTABL ... 2625311833

Anyway, I've repaired the speed governor and relubricated everything, which fixed a few problem, but the record still slows to a halt once the reproducer is placed on it, even if the speed is set to much faster than 78rpm. After taking apart the support for the tonearm, I noticed that the metal of the tonearm itself was cracked near the base (which I probably should have expected given that it is made of pot metal). Well, now I have a non-working phonograph which really hasn't cost me anything but time, and I would love to get it to operate again. Buying a new tonearm might be an option, although I would prefer not to unless it is the same part (the color and shape is pretty unique/cool) and is relatively cheap.

Do any of you know of a good way to rebalance the tonearm to put less weight on the record so it doesn't slow to a halt when played?

Thanks!

-Larry

PS: I can provide pictures if it would help give you a better understanding of the situation.

[Jerry B.]

Any tone arm should have very little friction when it is moved right to left as well as up and down. A pot metal tone arm that has limited movement can introduce friction and create problems with playing a record. If you have good tone arm movement I would look towards a problem with old springs in the motor.

Something like JB Weld could be used to fix cosmetic cracks in pot metal items.

Jerry B.

[52089]

Also be sure you are using a new needle (use each needle only once!) and a record that's not worn out or made of vinyl. Any deviation from the above will increase drag on your motor.

[lloprete]

Jerry-

Thanks for your reply! I think there is significant friction when the tonearm moves left to right (unless I gently lift the tonearm while doing so). I am pretty confident the motor is fine, since the records spin just fine without the tonearm on them.

As for the cracked pot metal, the portion that is chipped off is the bottom piece of the tonearm, where it meets the base. I have attached a few pictures. The lip of the inner tube is chipped. My guess is that its original (pre-chipped) state provided more support for the tonearm and reduced friction. Do you have any advice/suggestions for how to go about fixing the improperly supported/balanced tonearm?

Thanks!

-Larry

[lloprete]

And yes - I am testing with a new needle for each try, and the record has played well on another phonograph, so I don't think it's the record. (Still, good advice to keep in mind for the future!)

Also, if I support the tone arm while it plays the records, it usually can make it through the whole record. Otherwise, it repeats (skips) and within a few seconds, slows down completely. I have been winding the motor to its max each time, so it's probably not the motor.

Please let me know what you think (hopefully, the pictures in my previous post help!)

Thanks!

-Larry

[Curt A]

Sanding the inside of the tonearm mount and the bottom of the tonearm itself (where it inserts into the mount) may help... Usually, the potmetal swells over time causing excess friction in the joints, so any place that moves could benefit from that treatment along with some lubrication. The tonearm should swing up and down and side to side without any restrictions. Don't over sand the joints to make them sloppy, but until they move freely and smoothly... Hope that helps.

[Curt A]

Also, it looks like there might be a groove at the base of the tonearm that might have had a circular spring or something to hold the arm in the base - a previous owner may have tried to remove it and therefore chipped the bottom... Not sure, as I am unfamiliar with this machine, but normally something keeps the tonearm attached to the base so it won't just pop off...

[lloprete]

I could try sanding it, although I gave a little dry lubricant a try with no success. It rotates freely enough when supported, but once the tonearm is let go, it doesn't swing side to side as easily.

Also, it looks like there might be a groove at the base of the tonearm that might have had a circular spring or something to hold the arm in the base - a previous owner may have tried to remove it and therefore chipped the bottom... Not sure, as I am unfamiliar with this machine, but normally something keeps the tonearm attached to the base so it won't just pop off...

Good observation - I think you're probably right. That might be related to the friction issue. Do you have any recommendations for how to restore the tonearm to its original form (I don't have the pieces that chipped off since that was done by a previous owner)?

Thanks!

-Larry