Birch 600 Newbie Owner Questions

[JerryVan]

As Orthofan suggests, oil the joint at the base of the tone arm and repeatedly swing it back & forth. The hope is that doing so will loosen things up a bit. Removing the tone arm will require you to practically ruin the horn. These things were really not made to be serviced.

[doctor_of_jazz]

Got it - thanks all! I'll leave the barrier in place and work the oil through the tone arm base and see if that gets things moving.

[Inigo]

I never tried this, but it occurs to me that the product used for cleaning the vitroceramic or induction cooks, which are basically a thick black glass plate with the guts below, is a mixture of cream soap and a soft abrasive, usually limestone powder. If you could get a bit of this product through the jammed juncture and work it back and forth, it would help softening the juncture due to its soft abrasive... The problem would be how to clean the product after the treatment... The product is like the GoJo with abrasive, but this is not silica, but much softer, like limestone powder or similar soft mineral powder,
Also polishing compound might be used

[Lah Ca]

There has been good advice already offered. I offer my apologies if I duplicate some it it below.

I would guess that your machine is from the mid to late 1940s. The grease and lubricants in the motor are probably still in somewhat serviceable condition. If the machine works without issue (winds up without clunking noises, plays without clunking noises, plays without much mechanical noise once the needle is down on a record, plays a full side of a 12” 78 without slowing down or stopping, plays at a consistent speed without obvious wow and flutter, and can be set to 78 RPM with the speed control), I would just leave the motor alone for the moment.

If the machine has any of the issues above, people here can help you dig down into more technical things that might help.

I have a Canadian-made RCA Victor portable probably from 1941. It uses many Birch parts. Its tone arm and reproducer (the round thing on the end of the arm that the needle goes into) look identical to yours.

So the tone arm.

1) It is made of pot metal. Pot metal often naturally crystallizes with age making it very prone to metal fatigue and breakage. Be very gentle with the tone arm.

2) I am quite certain that the base of the tone arm is fixed to the motor board (the wooden top plate) with bifurcated rivets rather than screws. The machine was made quickly and cheaply. To take the tone arm off for servicing will be very difficult. As others have said, you will have to remove the paper horn. Then you will have to drill out the rivets. And then I believe that once the arm is off there is no easy way to separate it from the base anyway. It was not made to be serviced. The best thing to do is to leave it alone. Lubricate the area between the base and the tone arm lightly with a good quality machine oil (I use a modern synthetic), work the arm back and forth gently, repeat oiling if necessary, and keep working at it until it moves more freely. Mine moves freely now but it is still a little rough, and it may have been so when it was new.

3) Moving out along the arm towards the reproducer you will come to another joint where the arm’s forearm is attached. As helpful people here pointed out when I was struggling with my machine, this joint is very important.

3a) The joint allows vertical movement of the forearm and reproducer, allowing the tone arm to accommodate vertical undulations in a record and to accommodate records of different thicknesses. So the forearm must move quite freely in the lowermost part of of its range of movement. If it does not, some records may stall the machine.

3b) The movement of the forearm should be quite stiff, however, in the uppermost part of its range of movement. The movement of arm at this joint also allows the reproducer to be raised up to ease the changing of needles. The stiffness of movement here locks the reproducer up and prevents it from crashing down, possibly damaging a record.

3c) Pot metal swells with age sometimes, and this joint can be seriously seized up. It was on my machine, causing lots of problems. There is a set screw which holds the arm in place. It can be removed (gently), and the forearm can be removed (gently) from the arm. This may require oiling and gentle pressure, persistence and patience. Once the forearm is removed, it and its socket can be cleaned, sanded (steel wool), polished, lubricated, refitted, and retested (repeat as necessary until the movement is free at the bottom while remaining stiff at the top).

4) At the end of the arm is the reproducer. It is held on with a set screw.

4a) If yours is like mine, it is not one of the truly great reproducers, but it is surprisingly a very good one, sound-wise anyway. It performs well, accommodating most electrically recorded shellac records. It has an aluminum diaphragm. On some reproducers, the diaphragms are riveted into place. If yours is riveted, there isn’t a lot you can easily do to service the reproducer other than putting a tiny drop of oil on the pivot points of the needle bar (the assembly that holds the needle and connects to the diaphragm). If your reproducer comes apart with screws, it might be possible to replace gaskets in it, but with a 1940s machine this might not be necessary (yet).

4b) The joint between the forearm and the reproducer. There is a strip of red rubber-like material rolled up to form a throat gasket here. It should seal the joint completely, not allowing air/sound from the reproducer to escape at this joint. Sometimes this gasket material has shrunk and become brittle and crumbly, and things are not well sealed. You can go to a plumbing or hardware store and buy similar gasket material (same colour even) and make a new gasket. The only tricky thing here is cutting it to the right length so that the ends meet tightly without any overlap.

4c) The set screw on the reproducer also allows the angle that the needle engages the record at to be set. Common advice suggests that the 55 to 65 degree range is normative. A steeper angle may increase surface noise and increase drag (friction between the record and the needle which can slow or stop play). A lower angle can reduce drag and possibly surface noise at a cost of other sound quality perhaps. You can adjust things here to your taste in relation to how it sounds. Within a limited range the set screw might also allow you to set needle overhang/tracking error (the path of needle across the record is an arc—the movement of the cutting lathes during recording an manufacturing was linear—the arc of the needle path will intersect the linear path of the lathe at two points—the overage and underage of the arc in relation to the linear path should be minimized/optimized). Some people advise that the tip of the needle should be able to touch the spindle at the center of the platter. On an inexpensive machine, it may not be possible to adjust things so that you have a good needle angle for play and a good angle for overhang. Focus first on the good angle for play.

[doctor_of_jazz]

Thank you for that detail Lah Ca! I've decided to oil the base only, which made quite a bit of difference. I bought 100 Soft Tone needles and wound this baby up. Although it is skipping and I am not sure where I am going wrong. The elbow of the tone arm is slightly loose.

I've captured a video of the playback showing skips, and the looseness of the tone arm elbow. Also grabbed a picture of the needle. Does anything look obviously wrong? If you listen carefully, you can hear my wife yelling at me in the background.

Same files may easier to view here on my Google Photos: https://photos.app.goo.gl/VRgyqyaMbhqQ58vm8

[JerryVan]

It would appear that your tone arm is still binding too much.

[Lah Ca]

Does it skip with all records?

Does it skip only at the beginning of a record? What happens if you start play from the middle of a record?

It is hard to tell from the picture, but the needle you are using looks rather blunt. Is it a new needle? If you are experimenting with old needles while you wait for new ones to arrive, the needle may be part of the problem.

Is the machine set so that the platter and motor board are relatively level?

Or it may be as JerryVan says, and you need to keep working on freeing up the arm.

[Lah Ca]

It also seems that with your reproducer things are not quite in alignment. It is hard to tell though from your video clip. Many web/phone cams have a slight fisheye effect to increase field of view.

Yours (screenshot from your video):

reproducer.jpg (23.33 KiB) Viewed 1157 times

Mine:

Make sure the reproducer is set on the end of the arm properly with the arm fully inserted. Set the needle angle. Put the needle down on a record without starting the motor. Take a picture similar to mine and post it here.

[Lah Ca]

I looked at things in your Google account. It also looks like there is way too much slop/play in the elbow joint of the arm (quite the opposite problem to mine).

https://photos.google.com/share/AF1QipN ... N1ajF2TFBB

Can you slowly and carefully tighten the set screw to see if this tightens things up a bit. [Edit: On closer inspection, the set screw looks as if it is fully tightened and the lock washer under it is squashed flat.]

[doctor_of_jazz]

That wiggle would make sense. I pulled the elbow off and put it back on, it's a little better, but not as tight as I would like. Does not seem to be a way to adjust on the table itself. Wondering if I'll need to add something in there (small strip of paper) to fill the gap if needed.

It is a new needle and I only sampled a few spots, but will have to check further along the record. I readjusted it's placement which seems only impacted by that small thumbscrew which holds it in place.