defender-IA
New Member
Hello everyone, I hope you are all well.
I'm having a few issues with a Sharp VZ2500 portable music centre (ghetto blaster) from the 1980's, and I'm looking for some advice as to where to start looking for the cure, if someone would be so kind as to advise.
This player has a couple of issues. The first is no tonearm tracking and the second is no auto detection of record size.
The tonearm drive belt has been replaced with a new genuine sharp belt. The forward/ reverse/ play is working correctly (apart from not auto finding 7 inch records and not tracking).
The tracking works on a photo sensor, that as the tonearm gets pulled off centre, the flag on the cartridge mounting allows the light to hit the detector, which then is supposed to energise the tonearm motor to turn, which, when the tonearm flag blocks the light, it stops until required again.
This has worked a couple of times by itself, but apart from this, I have to wheel the worm gear to make the tonearm move. The last time I wheeled it, the tonearm started to work properly afterwards.
I thought this may be because something physical was partially seized or something binding that was overpowering the motor. So I lubricated the worm gear and cog pins with some wd40. It stopped working again at the second play, so I slipped off the drive belt to disconnect the gearing from the motor. Played a record and checked to see if the motor was energising as the detector moved to where the carriage should have moved .. nothing.
It appears that no voltage is getting to the motor to move the tonearm. I would say the photosensor is at fault, but this issue is on both side 1 and side 2 of the player. The likelyhood of both being shot is unlikely ?
In regards the auto detection of record size, I have both LED's in the front of the player lit at all times. I understand that the photo transistors work by when one of the LED's gets the light blocked, then it knows what size of record is in there and cues accordingly. It won't start anywhere other than if there is a 12 inch record in it. The only way of playing a 7 inch record at the moment, is to use forward and let the needle cue to the right point manually. I have even put tape across the photo transistor for the 7 inch and absolutely no difference.
Could anyone please advise on this issue ? as after 3 weeks of measuring, trying different approaches etc, I'm at a loss as to where to go next.
Kind Regards
I'm having a few issues with a Sharp VZ2500 portable music centre (ghetto blaster) from the 1980's, and I'm looking for some advice as to where to start looking for the cure, if someone would be so kind as to advise.
This player has a couple of issues. The first is no tonearm tracking and the second is no auto detection of record size.
The tonearm drive belt has been replaced with a new genuine sharp belt. The forward/ reverse/ play is working correctly (apart from not auto finding 7 inch records and not tracking).
The tracking works on a photo sensor, that as the tonearm gets pulled off centre, the flag on the cartridge mounting allows the light to hit the detector, which then is supposed to energise the tonearm motor to turn, which, when the tonearm flag blocks the light, it stops until required again.
This has worked a couple of times by itself, but apart from this, I have to wheel the worm gear to make the tonearm move. The last time I wheeled it, the tonearm started to work properly afterwards.
I thought this may be because something physical was partially seized or something binding that was overpowering the motor. So I lubricated the worm gear and cog pins with some wd40. It stopped working again at the second play, so I slipped off the drive belt to disconnect the gearing from the motor. Played a record and checked to see if the motor was energising as the detector moved to where the carriage should have moved .. nothing.
It appears that no voltage is getting to the motor to move the tonearm. I would say the photosensor is at fault, but this issue is on both side 1 and side 2 of the player. The likelyhood of both being shot is unlikely ?
In regards the auto detection of record size, I have both LED's in the front of the player lit at all times. I understand that the photo transistors work by when one of the LED's gets the light blocked, then it knows what size of record is in there and cues accordingly. It won't start anywhere other than if there is a 12 inch record in it. The only way of playing a 7 inch record at the moment, is to use forward and let the needle cue to the right point manually. I have even put tape across the photo transistor for the 7 inch and absolutely no difference.
Could anyone please advise on this issue ? as after 3 weeks of measuring, trying different approaches etc, I'm at a loss as to where to go next.
Kind Regards
