Exhibition needlebar adjustment problems

[B.B.B]

Question:

I have an Exhibition that I try rebuilding.

Everything goes fine, until its time to adjust the needlebar.
If I set the needlebar so that it just touches the mica, nor pushing or pulling, then the needle-holder part points slightly outwards.

See my poor, sad, MS Paint made illustration:

Exhibition_not_right.JPG (7.13 KiB) Viewed 2256 times

However, it sounds great.
But, it leaves a tiny amount of black dust on the needle after playing my Black Pattis on the VV-IV.
Not great at all.

So, to have the needle going straight down, I have to adjust it so it really pulls on the diaphragm. Not that great either.

I am not sure here & I really need some advice.
Does the angel of the needle matter, or is it only the needlebar-mica contact that is important.

I did of course have a good look at the soundbox & it doesn't look damaged at all, no signs of bent needlebar or such.

Anyone have any input or thought about this problem of mine?

All help appriciated.

[Brad]

Triple-B,

I have rebuilt many an Exhibition and have never seen this. I just took at look at one and the needle lies pretty much parallel to the plane that the needle bar from the pivot point to the center of the diaphragm lays. If these are not parallel, then it would suggest that the needle bar is bent.

If that is not the case then I would ask if you used the correct size rubber tubing and/or did you place tubing on both sides of the diaphragm?

If things lined up before the rebuild, compare the parts you replaced to see if there are noticable differences.

Finally, Check the pocket that holds the needle to make sure nothing is obstructing.

I would not play records until you resolve.

Brad

[B.B.B]

Well,
The tubing comes from a respectable dealer, standard white material.
Nothing in the needle "holder"

Maybe then the needle bar is bent after all.
It was in a sad state when I got it.
Dirty, broken diaphragm, no rubber flange, so I never had a closer look at it
before i tore it apart.
It doesn't however show any signs of being abused or dropped or something.

[Steve]

Don't panic if the needle is not 90 degrees, few are spot on anyway. I have one or two which are a little out and it won't chew up your records! Now, 60 degrees would be a different story OR use fibres!

[B.B.B]

I did a Thorens like this a few weeks ago, and the needle bar was slightly bent at the 90% angle up near the mica. I was bit worried about it snapping when I bent it back, but it didn't. I guess it would have been safer to heat it first though.

If everything else is okey, then the needlebar must be bent.
The small springs that adjust & holds the needlebar in place looks fine too, otherwise they could be causing the problem maybe?

I'm a bit queasy about bending the needlebar, but if one applies some heat w/ a soldering-iron & then try to bend it a little, very gentle, it should be okey.

Don't panic if the needle is not 90 degrees, few are spot on anyway. I have one or two which are a little out and it won't chew up your records! Now, 60 degrees would be a different story OR use fibres!

Good to hear, but this is not only "cosmethic" It chews up my records, or so I've learned anyway, that when there is black dust on the needle after playing, then something is wrong

I like fiber, thats why I eat oatmeal every morning.
Fiber on records is another story..They are just not loud enough for me

[Phonolair]

I'm a bit queasy about bending the needlebar, but if one applies some heat w/ a soldering-iron & then try to bend it a little, very gentle, it should be okey.

Be very careful with your soldering iron because on the Exhibition the small flat part that the mica diaphragm screw attaches to is soldered to the tip of the needle bar. Too much heat and your needle bar will separate from the screw mount and mica diaphragm.
Regards, Larry

[wjw]

Be very careful with your soldering iron because on the Exhibition the small flat part that the mica diaphragm screw attaches to is soldered to the tip of the needle bar. Too much heat and your needle bar will separate from the screw mount and mica diaphragm.
Regards, Larry

Oh, that's funny. Some time ago I repaired this part of the needle bar by soldering. I thought that it had rusted in two! Still works just fine.

[B.B.B]

The way I checked it, and it became obvious, was to remove the needle bar & screw the mica onto it. It was then easy to see that the mica wasn't sitting parallel to the needle chuck (& in the case of this Thorens, the back side of the needle bar). With the diaphragm still attached, I got the long nose pliers to the top & kinked it in the appropriate direction.
It won't hurt to heat the bar with the mica attached obviously, but just don't overdo it. The amount I had to bend mine would have been invisible to the naked eye without the mica as a guide

Great information to have, thanks!

Be very careful with your soldering iron because on the Exhibition the small flat part that the mica diaphragm screw attaches to is soldered to the tip of the needle bar. Too much heat and your needle bar will separate from the screw mount and mica diaphragm.
Regards, Larry

I didn't know that. Still, every guide to rebuilding a Exhibition, states that in order to melt the beeswax, you should heat the needlebar w/ a soldering iron.
And that works just fine. But on the other hand, then you don't apply the soldering-iron directly at the top, but more on the middle of the bar.
So when doing my bending, I'll take care not to overdo it, nor heat it up too much close to the delicate part.

[Steve]

Still, every guide to rebuilding a Exhibition, states that in order to melt the beeswax, you should heat the needlebar w/ a soldering iron

Do they? I've never seen that comment made before. I think it's nonsensical to heat the stylus bar unnecessarily. I've never done that with any of the rebuilds I've carried out and I've done quite a few now.

All I ever do, is roll up a tiny piece of beeswax from a stick between my thumb and forefinger until it is into a nice neat ball shape. I then place it carefully over the end of the screw (or head if you're doing the reverse side too) and place the tip of a heated screwdriver onto it. The wax melts instantly and runs (hopefully) into a nice circle around the end of the bar where it meets the diaphragm and should achieve a good seal. A bit of trial and error may be necessary to perfect it but I have never heated the stylus bar and can't understand why you would need to?

[B.B.B]

Still, every guide to rebuilding a Exhibition, states that in order to melt the beeswax, you should heat the needlebar w/ a soldering iron

Do they? I've never seen that comment made before. I think it's nonsensical to heat the stylus bar unnecessarily. I've never done that with any of the rebuilds I've carried out and I've done quite a few now.

All I ever do, is roll up a tiny piece of beeswax from a stick between my thumb and forefinger until it is into a nice neat ball shape. I then place it carefully over the end of the screw (or head if you're doing the reverse side too) and place the tip of a heated screwdriver onto it. The wax melts instantly and runs (hopefully) into a nice circle around the end of the bar where it meets the diaphragm and should achieve a good seal. A bit of trial and error may be necessary to perfect it but I have never heated the stylus bar and can't understand why you would need to?

http://www.nipperhead.com/old/rep_exhib.htm <-One that states it
Another source is the sheet Walt Sommers provide when you buy soundbox parts from him.
3rd source is from several posts on a Board that no longer exists...

But, thats not really important, your way, with the screwdriver almosts seem easier.

Shane, real classy to use old cylinder wax, talk about NOS