Orthophonic Sound box - removing needle-bar from Cover ?

[De Soto Frank]

Ok, new question.

I have read Wyatt Markus' ( Mica Monster ) thorough tutorial on rebuilding the Victor Orthophonic Sound Box.

I have gotten brave, and started working on the one from my Great-Grandmother's VE 8-12X, and it is apparently one of the most pristine OSB in existence. No trace of Pot-metal disease.

I am the first person to work on it since it left Camden in 1927.

I have the spanner ring out, back plate out, bearings and race-sleeves out. All is going really well.

At this point, I want to avoid doing something stupid.

How is the needle-bar installed on the cover: was it somehow snuck-in in one piece, or was the needle-bar slipped-in through the bottom, and the tapered pivot-bar then pressed-in through the bearing holes ?

I would LIKE to remove the diaphragm and needle-bar, but not if this involves unsoldering the bar from the spider, etc.


Help a pilgrim avoid doing something he will regret for the rest of his life...

(decaf)

[Mr Grumpy]

I'm pretty sure the pivot bar is pressed in through the bearing holes.
When I rebuild an Ortho, I try to avoid trying to separate the pivot bar and needle bar
rather than try to avoid un-soldering the diaphragm. I use a thin tipped soldering iron
that can reach in through the holes on the face of the reproducer and touch the needle bar/spider.
It usually takes a second to release.

When I reassemble, I put some flux on the tip of the needle bar and the hole in the spider.
Line them up, melt some solder to the tip of the iron, then touch it against the flux.
It will quickly flow into the hole and you have a connection.

The alternative is to use something like a really small socket or tube to place around one side of the
pivot bar while you tap on the other side with a hammer and punch. This is done through the bearing holes and
always seems more daunting then soldering.

Good luck Frank, it really isn't that hard and when you're done you'll wonder
why you didn't do it earlier!

[De Soto Frank]

Vince,

Thanks for the suggestions and the encouragement.

What do you use for flux - rosin or paste-flux ?


I think I would sooner un-solder the bar from the diaphragm than risk damaging that pivot-bar.


( I'll find a junker to experiment on... )


Frank

[Mr Grumpy]

I'm not sure of it's technical name, but I use a liquidish (jelly) type of flux I bought at the electronics store
for re-capping my radios. I also have a paste type that I use for soldering copper plumbing pipes
but find this didn't work too well when re-capping so I didn't bother trying it when rebuilding the
reproducer.

[De Soto Frank]

Well, if you got it from an electronics supply, then it would be along the lines of rosin.

The acid-flux used in plumbing is generally regarded as too aggressive for electronics / fine work.

[JerryVan]

Well, if you got it from an electronics supply, then it would be along the lines of rosin.

The acid-flux used in plumbing is generally regarded as too aggressive for electronics / fine work.

Just buy some "rosin core" solder. The flux is built in. Really though, you need so little solder that the flux is almost unimportant. Most times I've found that the remaining solder from the original assembly just remelts and the joint is good to go. Think of it, unless a gob of the original solder falls off, you've never actually removed any. Still, having some new solder on hand, and using it sparingly, is not a bad plan.

[JerryVan]

I have the spanner ring out, back plate out, bearings and race-sleeves out. All is going really well.

Frank,

Did the bearing race sleeves slide out with some ease? They should be press fit but, even with excellent pot metal housings, there is still a tiny bit of growth that allows the sleeves to get loose. When I reinstall the sleeves, I usually put some Loc-Tite on them to assure that they are firmly held in place. Otherwise, they will vibrate in their mounts and cause a "buzz" or rattle when playing a record.

Reinstalling the bearings can also be a nightmare. I temporarily place a small rubber o-ring in the end opposite the side I'm working on. This helps to stabilize the needle bar somewhat. In the side I'm putting bearings in, I fill the bearing pocket with some light grease. Not that grease is needed but, it holds the bearings in place as one-by-one, you carefully install them. With all the bearings installed, on both sides, I push them down, one-by-one, with a toothpick until they are snug between the sleeve and the taper of the pivot pin. If the pin is not sitting in the middle of the sleeve it means the bearings on one side of the pin are seated deeper than the other and some adjustment and repositioning is needed. I suppose at this point you could flush the grease out but I never bother with that.

[welshfield]

I dunno guys. All these details reinforce my resolve to send the thing out to a pro to rebuild. Why risk any possible damage????
John

[De Soto Frank]

Update...

Had a day off, and decided to spend some time on this.



Jerry - the bearing sleeves didn't quite "fall-out"... one came=out with the remains of the rubber bushing when I dug at it with a screw-driver. The other one popped a bit "proud" while I was manipulating the needle-bar, and I was able to grab it with tweezers and extract it.

I am cleaning things-up one side at a time, I cleaned and polished the bearing sleeve, separator washer, and tear-drop cover ( dug-out the fossilized rubber from the grooves ).

One thing I noticed that struck me as a little odd: the center-hole in the separator washer seemed to be off-center. At first I thought this was just a manufacturing goof, but then I checked the washer from the other side, and its center-hole is off-center too.

Has anyone else found this in an OSB ?

At around this point, my wife decided I could be doing "something more productive", so I had to put this aside for the day.

I do have a new set of bearing balls and some small rubber tubing I purchased from APSCO in 2001, so I will probably put these to good use now.

[De Soto Frank]

I dunno guys. All these details reinforce my resolve to send the thing out to a pro to rebuild. Why risk any possible damage????
John

John, after taking apart four out of the six OSB I have on-hand, I think the greatest challenge / night-mare is bad pot-metal.

The pot-metal in the OSB from my Great Grandmother's machine is darned-near perfect, and it is the only one of the six in that condition.

The rest range from two that are definitely rebuildable ( pot-metal is starting to deteriorate, but still usable), to another one that is borderline, a fifth that is probably parts-donor, and the sixth is definitely a junker/ parts-donor - the pot metal is that cracked / crumbly.

The main issue I found is that when the back-plate starts to crack and swell, it likes to cause the retaining-ring to jam, and often to crack across its section, and will probably come-out in pieces. One of the six went this way, last night. ++

Aside from that, if you have a reasonably steady hand, good tools, quiet work-space, and the desire, I think these can be rebuilt at home...

But then again, I found-out years ago that HO trains are too small and delicate for my ham-hands, so I guess we have to recognize when we're getting beyond our comfort-zone...

I hope I get the OSB from Great-Grandma's machine together again and working better than when I started... fingers-crossed.

Frank