BIC 940 Parts

[dianemo10]

I've had my BIC-940 turntable in a repair shop for several months. The repairman says I need a part & he hasn't been able to find it. It's a white rubber ring. I have a photo of it.

I originally took the turntable in because it wouldn't move, except by hand. The repairman said it was gummy. When he gave it back to me, the arm would not return after reaching the end of the record and would not start at the beginning of a 33 1/3 record. It would go directly to the 45 point. I gave him the directions I found on the web-- to clean off the oil in these areas. Now he says the white rubbber ring needs to be replaced.

Does anyone know where I can get the part?

[Doug G.]

Whether or not the white donut needs to be replaced depends on its present condition.

Is it falling apart or extremely hardened? Either of those two situations would, indeed require replacement. If it's just oily, it can be cleaned and will work again. It needs to be absolutely clean, however.

Some owners have found small regular O-rings to use as a substitute with success.

The mispositioning of the arm at the start of play is a separate issue and requires the cleaning and relubing of the two metal cam following levers that move into position to stop the arm at different locations.

Doug

[dianemo10]

Doug -- Thanks for the info!! I will pass it on to the repairman.

[Doug G.]

You are welcome and if your repair guy needs any more information, feel free to relay the questions to me. I have had a lot of experience repairing BICs.

Doug

[dianemo10]

Doug,
I gave the repairman the info you provided. We looked at the donut-- it is not falling apart nor hard. He says it moves/turns & he thinks it shouldn't, which is why he thought it needed replacing. He also said he cleaned it. Should it turn when it's in place?

He doesn't have a schematic for the turntable, only the user's manual that came with it. So, I think he's not comfortable with taking it apart, although he had already taken the donut out.

Any advice?

Thanks, Diane

[Doug G.]

The way that mechanism works is thus:

There is an extension on what's called the arm lever underneath the base plate. This is attached to the lower end of the tonearm and swings with it.

This extension, when the arm gets near the center of the record, pushes on a trip lever attached to the big red cycle cam.

The trip lever moves the trip pawl via the little white donut. The donut is mounted on the pawl in a kind of groove and rests against the trip lever. Thus, there is friction between the two parts and the pawl moves when the lever moves.

As long as the arm progression is slow, like when in the recorded groove section of the record, the pawl gets pushed back out of the way by the stud on the platter spindle. This is also why the white donut is there so the two parts can move separately. The trip lever needs to stay in the same place while the pawl is pushed back by the stud.

This is called a velocity trip mechanism, by the way.

When the stylus/arm moves quickly as in the lead out grooves, the pawl moves into the way of the stud on the platter spindle and gets pushed to turn the big red cam until the gear teeth engage and the cycle starts.

The donut should fit tight enough in the groove on the pawl so it doesn't easily turn. If it seems to turn too easily, I suppose a very small amount of superglue could be used to attach it to the pawl. It doesn't need to move in the groove. Just against the lever surface.

I hope this is clear.

Doug