Diamond Disc 250 horn alignment question

[fran604g]

I must say that in the photo showing the reproducer positioned in the first rotation of the groove, the neck of the horn looks too far to the left. I suspect that the top piece of the horn (the mostly horizontal section where the reproducer attaches) was separated from the lower section and replaced at an improper angle.

The top piece should be rotated clockwise on the lower section until the neck of the horn sits directly behind the reproducer when it's at the start of the record.

George P.

That could be, George.

For comparison, here's a photo of the horn throat and reproducer tube on my C250 with a straight edge alongside, note the uniform parallel gap, that follows the taper perfectly.

Also, upon further inspection of the horn compartment, I noticed that it is not possible for the horn to come in contact with the inside of the grille piece, as the upper part of the horn tube contacts a stop on the turntable trim piece before that can happen. My horn edge is 9/16" from the inside edge of the cabinet horn opening. See pictures below.

I hope this helps understand exactly where the problem is.

Best,
Fran

[Edisone]

Could the 10-12 'key' be hitting the cabinet? Maybe try removing that, to see what happens ...

[phonogfp]

Let me illustrate my earlier point with photos.

PHOTO 1:
The photo below shows an Army/Navy Disc Phonograph currently under restoration, but the concept is identical. The top section of the horn has come loose from the lower section.

PHOTO 2:
Below, the top section of the horn has been replaced at the proper angle. Note that the neck of the horn is directly behind where the reproducer mounts.

PHOTO 3:
Below, the top section of the horn has been replaced at an IMPROPER angle. Note that reproducer will be too far to the right of the turntable.

PHOTO 4:
Finally, the IMPROPER angle of the top section results in the neck of the horn being too far to the left when the reproducer is in position to play the beginning of the record. By the end of the record, the horn will be hitting the cabinet.

I hope these photos make my point clearer than my inadequate word-smithing did.
George P.

[fran604g]

George, great images that illustrate your earlier point, thank you for them! Combined with the rest of the information here, we might be able to determine a quick way to definitively check the geometry of a DD horn. i.e. With the horn placed against the far left "stop", check the position of the reproducer stylus on a record?

I wonder if it would be helpful to assemble all the information in this post as a guide, and post it in the "Tips, tricks and tutorials" section, or do you think this type of problem is far too obscure? I remember reading a post in which an Edisonic (I believe) had a horn come apart at the knurled reproducer locking ring. I'll see if I can find the post, and if someone came up with a solution for re-attaching it.

Best,
Fran

[fran604g]

Hiya folks,

I took a couple of more photos showing the proper alignment as it is on my C250. Combined with the previous images provided by the OP, George, and myself, this should be helpful to diagnose overtravel and under travel issues of the Diamond Disc Type B mechanism related to the (topside) safety stop, horn construction and positioning of the reproducer. It should be noted that in addition to these alignments, the bottom of the reproducer cup should be held precisely parallel to the record surface.

If I've missed anything directly related to this issue, please comment.

Best,
Fran

The first image showing the 7" mark on my tape measure was taken exactly straight on from setting the camera atop the center of the lid lock mechanism. The measurement is taken from the right inside edge of the turntable compartment. The stylus is in the first groove of this record.

The second image is used to illustrate the stop position of the reproducer. The horn is against the turntable trim piece "stop", and this positions the stylus ⅛" away from contacting the record label (in the "dead wax" of the record, placing the stylus a significant distance from the final groove of the record).

[mikejk]

Thank you everyone for the replies on this topic.
Edisone, the 10-12 button horn stop is clearing, but thanks I never thought to check that.

Fran, thank you for all your help, but George has picked up precisely on what I have been trying to convey, and that is that the top elbow is simply in the wrong position. When I first started using this machine, I always thought that I had to move the horn over a long way to start a record in comparison to the other DD floor models here. After we use these machines so often, I think we can tell quickly when something isn't right.
However, I must say that I do not feel that the machine has been tampered with, and that this is the way it came from the factory. ?? To suggest this, I have taken the same two photos that Fran has posted of the measurement and stylus position, and they appear to be the same.
In my earlier photos, it can be seen that the horn throat is not directly behind the reproducer with the stylus in the starting groove.
George, your post and the pictures show it all clearly to me, and I feel that rotating the top elbow slightly to the left would solve the problem and align the reproducer more correctly like on the rest of my floor models. Therefore, I do intend to move it. Is the joint between the top elbow and the black horn throat a soldered joint ? If moving this elbow is not a good idea please say so.
Thanks,
Mike

[phonogfp]

Is the joint between the top elbow and the black horn throat a soldered joint ? If moving this elbow is not a good idea please say so.
Thanks,
Mike

If it were mine, I'd try moving it. I believe these joints were originally soldered, but if yours was "fixed" later on, who knows what was used? (I'll be using an adhesive on this Army/Navy horn.)

You probably already know that it would be a bad idea to torque that horn while it's installed in the cabinet. It's attached to the support tube in only two places, and those solder joints can and will fail if too much pressure is applied. However, it may not be necessary to remove the horn from the mechanism. By removing the entire mechanism/horn assembly from the cabinet and laying it on its side, the horn can be stabilized against the floor or workbench with one hand while you coax with the other.

If you need instructions on safe & easy removal of these Edison DD mechanisms, Fran has developed & posted good ones in the past. I'll bet he would re-post them if asked nicely!

Good luck!

George P.

[fran604g]

I would be happy to assist in any way I can!

Fran

[mikejk]

Fran and George,
I want to thank you guys for your support and help with this topic.
Who am I to think that I would know better than the Thomas A. Edison Phonograph Works!
I have had the mechanism out of this one already to fix that soldered joint at the top horn bracket, both the bracket and the pivot tube came apart, and I wouldn't want to mess that repair up.
When I have a clear mind and some time, I am going to try rotating the elbow.
Will heating the elbow discolor the gunmetal finish ?
Of course, I could just leave it alone, it plays great!
Thanks again, Mike

[fran604g]

Fran and George,
I want to thank you guys for your support and help with this topic.
Who am I to think that I would know better than the Thomas A. Edison Phonograph Works!
I have had the mechanism out of this one already to fix that soldered joint at the top horn bracket, both the bracket and the pivot tube came apart, and I wouldn't want to mess that repair up.
When I have a clear mind and some time, I am going to try rotating the elbow.
Will heating the elbow discolor the gunmetal finish ?
Of course, I could just leave it alone, it plays great!
Thanks again, Mike

Hiya Mike,

It just might. I don't really know what the process was used to "plate" these parts. You could always just look for a new horn assembly. They seem to be plentiful in gold, maybe you can find a gunmetal finished one from another model -- just make sure it's a "250" size horn.

Best,
Fran