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SL-1700MK2 Tone Arm End of Record Sensor Repair

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SL-1700MK2 Tone Arm End of Record Sensor Repair

Postby Sleepwalker65 » 03 May 2018 23:31

It looks like the sensor that detects the end of records on my SL-1700MK2 was damaged by the prior owner. The service manual doesn’t give much detail on this sensor, but I believe it uses a metal “shutter” that moves with the tone arm through an optical sensor. It seems there is a series of parallel slots cut into a piece of metal attached to the “shutter”, and a matching piece on one side of the optical sensor (I guess the receiving side) to generate a series of pulses for the control circuit to calibrate itself to. Problem is the piece with the slots on the sensor has been attached on 2 sides with weak joints, one of which had been broken.

Any opinions on my assumptions of how the sensor is supposed to work, and / or advice on repair?

Thanks as always!
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Re: SL-1700MK2 Tone Arm End of Record Sensor Repair

Postby milketizmo » 04 May 2018 14:53

There's a little rubber covered opening on the backside of the tonearm base. It's there to calibrate the autostop function. Theres a little more about that in the manual. Sorry if this did'nt Help.
Best of luck.
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Re: SL-1700MK2 Tone Arm End of Record Sensor Repair

Postby analogaudio » 05 May 2018 01:55

Please can you provide pictures showing what you describe?
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Re: SL-1700MK2 Tone Arm End of Record Sensor Repair

Postby Sleepwalker65 » 12 Jun 2018 03:32

Well, I’m making progress. This past weekend, i re-assembled the tonearm base, after straightening the bent “shutters” on the optical arm position sensor. I was never more thankful that I had the presence of mind to take a bunch of photos when I disassembled the tonearm base. With a little patience, I got it all back together, except for the tonearm wire and muting switch (waiting on a special wire stripper for the KAB silicone Super-Flex tonearm wire). Much to my surprise, the arm’s auto-return and electrically operated cuing control work perfectly! Now I still have to solve the mystery of the innefective anti-skate spring (another thread), but I’m one big step closer to playing records on this 39 year old turntable. Thanks again for your continued Help and encouragement!
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