BIC 940 auto-return not working

[bangsezmax]

I have a BIC 940 which works perfectly except for the auto-return at the end of the record.

I looked through AK and saw that there were issues about the trip pawl being gummed up, but I'm unsure if that's the issue here.

Under the main red gear, I see the small aluminum tab that's supposed to engage the process, but it never does, even when I manually make it move into end-of-record position. I can see that this tab engages the levers on top of the gear, and all seems to be loose and moving easily. But auto-return still never engages.

Any clues?

 

[eb2jim]

I came across an old BIC once where a previous owner had gone under there and disabled the auto-trip metal part. I am guessing they were buying into the voodoo that auto mechanisms are bad and make turntables sound bad. But either way - gummy or parts removed - you are going to have to go in there and take it apart, clean, lube, and reassemble. And you will probably need a service manual. You might even need to buy a part or two from Turntable Experts. But BICs are much more repairable than most old decks, so good luck!

 

[shimniok]

They are fun to work on, pretty simple mechanisms, overall. It was really rewarding to get mine fully functional again.

 

[sloober]

While on the BIC topic, where do you apply the silicone goo to slow down the cuing speed? I have some on order, but am not sure where to apply it, how much and how will this effect the adjustment screw for setting this speed?

I had to lube up my 960 pretty well as parts were stuck together under the table. It now starts and stops automatically and returns. John

 

[shimniok]

There's actually a thread on this with a service bulletin posted. Fairly easy to do:

http://audiokarma.org/forums/showthread.php?t=158521&page=2

Attachment is here: http://audiokarma.org/forums/attachment.php?attachmentid=86572&d=1207704067

You can get the goo from TurntableExperts.com (South Street Service): http://www.turntableexperts.com/html/bic.html -- at least that is where I got the stuff for mine. There is another place that sells equivalent 500,000wt goo.

 

[Doug G.]

As far as the end-of-record-trip, the arm lever on the underside and attached to the tonearm moves with the arm and the extension on it hits the little lever on the red cam as the arm moves toward the center of the record.

This little lever on the red cam, in turn, moves the little pawl via the little white donut-shaped washer.

As long as the movement is slow (i.e. the needle is still in the playing grooves) the boss on the platter hub will just push the pawl out of the way and there will be no trip.

However, with the rapid movement of the arm when the needle gets to the runout groove, the pawl moves quickly enough so it catches the boss and the red cam is pushed so the gear teeth engage the teeth on the platter hub and the change cycle begins.

The critical thing here is that there is friction between the little white donut and the other parts so the pawl does actually get moved. If there is lubricant or other slippery substance here, the lever on the red cam will move but the pawl will not.

Clean all of these parts well with a degreaser and do not lubricate them when reassembling.

Also, make sure the arm lever is actually hitting the little lever on the red cam as the arm moves. You can see this with the TT upright by looking through the clear bottom cover on the right side of the TT.

Doug

 

[bangsezmax]

As far as the end-of-record-trip, the arm lever on the underside and attached to the tonearm moves with the arm and the extension on it hits the little lever on the red cam as the arm moves toward the center of the record.

This little lever on the red cam, in turn, moves the little pawl via the little white donut-shaped washer.

As long as the movement is slow (i.e. the needle is still in the playing grooves) the boss on the platter hub will just push the pawl out of the way and there will be no trip.

However, with the rapid movement of the arm when the needle gets to the runout groove, the pawl moves quickly enough so it catches the boss and the red cam is pushed so the gear teeth engage the teeth on the platter hub and the change cycle begins.

The critical thing here is that there is friction between the little white donut and the other parts so the pawl does actually get moved. If there is lubricant or other slippery substance here, the lever on the red cam will move but the pawl will not.

Clean all of these parts well with a degreaser and do not lubricate them when reassembling.

That was it. :yes:

Thanks so much! What a cool place AK is.

I'm not much for working on auto-mechanisms, but these BICs seem like a nice and easy one to start learning on.