Nakamichi BX-100 problem and solution for auto-stopping when playing, FF or Rewind. Optical sensor.

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Nakamichi BX-100 problem and solution for auto-stopping when playing, FF or Rewind. Optical sensor.

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Nothingherefolks

Күн бұрын

Пікірлер: 13

@paulredshaw6301 3 ай бұрын

Thank you for the tip, I sprayed the sensor with isoprop and Voila! all works well

@nothingherefolks6218 3 ай бұрын

Glad it helped!

@fongfuhyong4191 Жыл бұрын

Hi, my Nakamichi MR-1 has this similar auto-stopping problem in playback mode after the machine warms up. It would work fine again after power off for a considerable period of time, but this problem keeps coming back after playing for 10-15 minutes. In addition, the digital counter would stop advancing at the same time. So, I removed the shut-off PCB to check the photo sensor (NJM5141) and found that the sensor output voltage to the base of transistor 2SC2812 (triggers shut-off pulse) would get stuck at 0.7V (after warming up) even though there is no IR reflected back to the sensor. As a result, the shut-off pulse would go to 0V when 2SC2812 conducts. The IR LED half emits a dim pink light when viewed from camera, hence I assume it's ok. Any advice on where to get the replacement photo sensor NJM5141 ? Thanks in advance.

@nothingherefolks6218 Жыл бұрын

I was lucky enough to find the part I needed on eBay for my BX-100 but after a quick search I wasn't able to find the part for yours. Maybe one of the cassette deck forums online has a buy/sell/trade thread? Good luck with your repair! I know that's frustrating.

@fongfuhyong4191 Жыл бұрын

Thanks for your prompt reply. This particular sensor is listed as NJM5141 in the MR-1 parts list but BX-300, CR-2, RX-202, BX-125 models all using NJL5141. Not sure what's the difference between NJM and NJL. Are you able to find any markings on the old sensor body? Thanks again.

@nothingherefolks6218 Жыл бұрын

@@fongfuhyong4191 I don't know the difference between the two. I checked the part number that I took out of mine and the board has two things printed on it: MD-8 and E46669-010V

@nothingherefolks6218 Жыл бұрын

@@fongfuhyong4191My player uses a belt for the counter, so I'm thinking since your counter is digital, it probably relies on the ir sensor for counting.

@fongfuhyong4191 Жыл бұрын

@@nothingherefolks6218 My sensor board has MD-8 and KS N30 printed on it. After comparing the schematic diagrams of some models using Sankyo transport, R603 resistor has a different value (750 vs 680 ohms) and the sensor on my board is NJM5141 instead of NJL5141. My sensor body (NJM5141) is printed with 1A 99, which I believe is a date or manufacturer code. If you apply 12V power to your old board, do you see the pink colour light emitting from the IR LED of this sensor when viewed from handphone camera? And what is the output of the sensor when the IR is reflected by a shiny object? Sorry for asking too much. Thank you very much.

@Kevin-lp3pu 5 ай бұрын

I have the Nakamichi BX-300 and it has this same problem. I wonder if this could be it?

@nothingherefolks6218 5 ай бұрын

It's possible but from what I've read, different models can fail for different reasons. So I can't say for sure. I know that some Nakamichi's can do this because of the counter.