Columbia Model 15 Grafonola, # 6 Repo - Advise Needed

[hiramk]

Hello all,

Issue 1: Reproducer Needs Rebuild

My reproducer is in need of a rebuild. New needles, few good records, etc. When it hits high or loud notes it makes a nasty vibration / distortion sound. I have been reading this forum for a few weeks and it sounds like dried gaskets and maybe the diaphragm is gone.

Issue 2: Head is Supposed to Rotate Backward

From what I understand, the head is supposed to rotate so it can rest without the needle eating into the wood. The head moves slightly back and forth. It is NOT seized, but it is definitely being stopped. Clearly I don’t know what I am doing.

Advice:

1. Does anyone have a diagram of the inside of the Columbia #6 Reproducer?
There is a pin at the bottom of the head, but it does not push in or pull out (see photos).

2. Is the head supposed to rotate clock wise or counter clockwise (facing the exposed diaphragm)?

3. The reproducer is pot metal. Should I attempt to rebuild the head without removing it from the shaft?

Sounds like a bad idea, but it really, really bugs me that the head will not rotate.

4. Who do you like for reproducer rebuilds?

I really like doing this myself. It is part of the bonding;) I am crazy about this machine and would rather have it professionally done than break it.

THANKS IN ADVANCE!

[De Soto Frank]

Hiram,

Another possible cause of raspy reproduction / blasting in loud passages can be loose needle-bar pivots. These are the tiny screws & nuts on either side of the needle-bar / chuck, that act as the pivot-point for the needle-bar. These screws have a pointed end, and should be set just tight enough to eliminate buzz / rasp, but not so tight that they inhibit the needle's "reading" of the grooves of the record.

I'm not what I'd consider an "expert" on Grafonolas, but they have been my main area of interest over the last couple of years, I have a several, have worked on quite a few, and have broken some parts along the way.

Columbia tone-arms came in two varieties: one that was made of formed brass, the later ones of die-cast "pot-metal".

I believe the one on your machine is brass; if there is a small blued/black steel screw on the back-side of the swivel elbow, this is a limit screw, which limits how high-up the tone-arm will swing, and its presence usually indicates a brass arm. Later pot-metal arms had no screw in the elbow, the limit being effected by internal stop-lugs inside the elbow.

If your arm has this limit screw, remove it, and swing the arm up so that it is vertical: this should release the tone-arm from the elbow. Then you can take the arm to the bench and work on things there.

The reproducer-head itself is die-cast, and sometimes the mounting-hub swells enough to jam inside the socket of the tone-arm.

If there's enough motion when you try to turn the reproducer to suggest that is not completely frozen, that is a good sign.

Looking at the diaphragm-side of the reproducer, the needle bar / chuck should be pointing down towards "7 o'clock" or so. This is the playing position. To remove the reproducer, it should twist clockwise with the needle-chuck stopping at "3 o'clock".

There is a detent-notch at each of these positions. At the "3 o'clock" position, there is a groove that allows the reproducer to be withdrawn from the tone-arm with some rocking / coaxing. Once removed, the retaining groove / operation becomes apparent.

I would not advise trying to rotate the reproducer between "7 o'clock" and "3 o'clock" going counter-clockwise ( passing through 6, 5, and 4 o'clocks ) - there is no retaining groove in this area of the hub, and things might really jam-up here.

That little pin on the bottom-side of the arm, at the reproducer socket, has a flat horseshoe spring inside, that pulls it tight into the reproducer hub. It is not designed to be manipulated by the operator or repair man. Ideally, it just floats in & out under spring pressure.

If the reproducer does not want turn, don't force... flow some penetrating oil ( Kroil or PB Blaster ) in around the detent pin, let it soak, and try again. If it still won't budge, put it in the freezer overnight, and try again the next day - sometimes a night in the deep-freeze will cause the things to shrink enough to un-jam.

If it still won't budge, it is possible to rebuild the reproducer w/o removing it from the arm.


See where all of this gets you...

Good luck...

Frank

[hiramk]

OMG. De Soto Frank you are a genius (or at least really, really experienced ).

First, the arm is brass. A friend loaned me a micro-camera. You can only stick it in your ear so many times before you start looking for something else. So I ran it into the internal horn. Interesting to see the stopper pin in the tone-arm at work and it clearly shows the brass that is not completely coated. Plus you were spot on with the black screw on the back. The tone-arm came off with zero problems. (see https://youtu.be/yC2Q9ue9iho )

Next, I loosened, cleaned, oiled and tightened the screws and nuts on the needle-bar. The buzz is 99% gone!!!! I cannot believe the difference. There is a tiny bit of vibration on really bad records, but good sound with a new needle and a clean record!

Now the bad news. I broke the nut off. Arg. There is enough of the original screw I can probably get it out, but I am going to enjoy it for a while.

Now that I can see the top of the gasket, it shows cracking. Something for a future project... I think it might be fine.

As for getting the head to turn, I think I have broken enough stuff for one night I will give it a good oiling this weekend and freeze it if necessary.

I will add the screw trick to the top 10 things you need to know. I cannot believe how big a difference it made.

I am adding you to my xmas card list!

- Hiram

[De Soto Frank]

Sorry about your broken pivot-screw... Ron Sitko is an excellent resource for such stuff, including gaskets, diaphragms, etc.

If you feel like trying to make your own pivot screw, ACE Hardware stores usually have an excellent selection of screws / etc.

I purchased some black, allen-head set-screws in the same size as the pivot screws ( #2-56 ? ), and used those. If you get them longer than needed, you can carefully dress the point to match the original profile, and if you're really motivated, cut-off the Allen- socket end, and carefully slot the end. I just put the Allen-screw on the lower-side, where it isn't seen during normal playing, and re-used the original lock-nut. The modern 2-56 nuts are significantly larger than the originals.


Regarding the gasket - try pressing your thumbnail into the exposed part of the gasket - if you can make an indentation, the gasket might be okay for a bit... if the rubber seems fairly resilient ( indentation "heals" after a while ), then even better.

If it is rock-hard, then it definitely should be changed. ( Inside one too... save any thin paper shims.)