Beogram 4002 5523 45RPM LP challenge

[Mark-sf]

I’m not sure what behavior you are describing. The turntable only detects a 45 record by virtue of it “seeing” the smaller diameter by receiving optical pulses from the ribs until the edge of the 45 is reached. Just prior to that a black line on the clear plastic mounted to the arm transport causes the speed to switch to 45. If you put a 45 12” record on the turntable should behave as if it’s a 33  LP and simply set down on the edge. You have to manually switch to 45 speed. Please describe what happens if you simply put the 45 LP on as if its is a 33 and change the speed right when or shortly after it lowers. If it is not lowering but continuing on, is your LP a colored vinyl that is partially transparent. This can cause it to not drop but is normal. Simply stop the arm with the > control and use the cuing to manually lower.

[david wilson]

Ok, sorry if that wasn’t clear, I am dealing with a 12″ 45rpm black record. When I press start the TT is in 33rpm mode two possibilites:

1. If i do nothing the arm goes past the edge then switching to 45RPM say halfway through then continues to the end and returns to the resting position. The arm does not drop
2. I have tried hitting the 45rpm button immediately after start and it does the same thing.

I am able to stop the arm and move it in whatever direction I need but the arm will not drop as if it is not seeing the record

I made a small “boot” to put over the optical sensor and it works well but does drop the needle a smidge early so you have to nudge it slightly with the button. It will return to the resting position once the end of the recording is reached correctly.

[Mark-sf]

The arm does not “see” the record when it gets to the drop point. This is controled by a black line on clear plastic guide attached to the arm transport. This guide can be adjested left and right to correct the set-down point for 12″ records though you need to remove the top plates. As to why it works on 33s bot not that 45, have you seen this occur on any other records? How does its thickness compare to your 33s? There is something about it that is causing the  light bouncing from the record to pulse telling the arm that there is no record there.  It is possible that the sensor circuit is mis-adjusted and the service manual describes the procedure but you do need test equiopment. One final possiblity is that your power supply has bad electrolytic capacitors that is causing a ripple in the voltage feeding the lamp and so the lamp is pulsing. If the 45 record is of different thickness or reflectivity, this could explain why it only happens on that one.

[AdamS]

Sorry for the obvious question, but your 45rpm LP isn’t a version made of clear or see-through vinyl is it?

[david wilson]

Thank you all for the great insight and feedback. This is the first and only 45rpm record that I have in my collection so it may be something unique to it. For  reference, it is a Mofi copy of “Kind of Blue” 180gram black vinyl. It is quite a bit heavier gauge but I haven’t seen this issue any 33rpm 180gram records. for trouble shooting purposes I started a 33rpm 180gram record in 45rpm mode and it drops correctly

[Mark-sf]

I too have that set and do not experience any problem. If you do not switch the speed and treat is as a 33 record, does it set down correctly? If it does, then I believe it’s a power supply issue with the higher current or faster rotation causing the detection circuit to malfunction. You can confirm this by using your 185 gr 33 record and switching the speed in the same way you did with the 45.

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