Viva-tonal reproducer screws - how tight?

[Stan]

I've been working on the reproducer for my portable Columbia Viva-tonal and was wondering if anyone can tell me how tight the two screws (pivots?) should be that point in to the needle bar (through the ball bearings). These are the 'needle bar screws' in the picture. Also, is there a recommendation for the two balance screws that press against the needle bar? (Only one is visible in the picture.)

The phonograph makes a buzzing sound during certain passages. I've noticed that loosening the needle bar screws increases the volume/fullness which is nice, but also seems to increase the buzzing/rattling. Maybe the sounds are caused by something else. (As you can see the diaphragm is a bit dinged up.) I've made sure everything is nice and tight.

Thanks!
Stan

[mikejk]

Stan,
Not sure if you have had a reply on this. The needle bar screws should be only just tight enough to hold the needle bar without any movement back and forth on the pivot points. Tighten them while trying to move the needle bar on the pivot points and stop tightening when any movement stops. When tightening the locking nuts, make sure the screws don't tighten more along with the nuts. The needle bar stop screws should not touch the needle bar while the bar is at rest, back them off if they are. This reproducer is very loud when used with Viva Tonal records and some that I have are down right deafening although the ceiling in my phono room is quite low and I think this amplifies things a bit.

Hope this helps, Mike

[Stan]

Thanks, Mike. I didn't know about the stop screws, and adjusted them as you suggested. Do you think a slightly dented diaphragm could be the culprit? It may be the machine itself - I noticed that when the sound board (the record storage compartment) is down/open, the buzzing is greatly reduced. This reduces the volume as well, but as you point out the machine is plenty loud.

Everything seems pretty snug (I made sure all the screws were tight) but it sorta sounded like what I was hearing was the machine itself rattling, more so on the low/bass notes.

Thanks again,

Stan

[mikejk]

Stan,
The dents in your diaphragm don't look too serious in your picture. The thing you want is, there to be free plunging movement of the diaphragm in and out, and no tears or holes in the diaphragm.

Often, buzzing comes from needle bar pivot points that are even just slightly too loose. Any metal parts that contact each other on the machine could be the culprit, this reproducer will vibrate the entire machine.

The needle bar stop screw is meant to stop the needle bar from traveling too far on loud passages so it won't damage the diaphragm, if it is in contact with the bar while at rest it will buzz.

I hope this makes sense, I am not always clear when trying to explain.

Which Columbia Portable are we talking about ? Mine is the very small, but very loud #109.
Mike