Sansui SR525, speed stable but fast

Huh, what is this fuzzy thing here? R018 1000038431.jpg. A quick check shows 1.1k across the R018 resistors.

Hmm. Seems like a false alarm, it's a speck of dust. Resistor and diode casing seems clean.
 
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Hi, the Switches are Just mechanicaly connected to the 3 way selector!

I Just finished the repairing of my 525. Main Problem was the yellow powerswitch. In closed State it hat a Résistance of 800 Ohms.
IMG_5758.jpeg
Resultate Output voltage 17 and -4,7 Volts.
I removed the switch and shorten the two white wires for testing.
Testing process:
The 3 way selector in off postion.
Then Plug in.
The motor should Starts Running as fast as it could, because of no Speed regulation is activ . Voltage is 18 V and - 4,9 V .
Voltage messurament was done After i also replaced the 3 Elcos on the Power Board.

If you Switch to 33 or 45 it should reduce the Speed. If you Just testing the Motor without the plate , the Motor stutters in 33 or 45 Mode. That’s normal , the smooth Rotation Just came up with the Weight of the plate.
I found an simular Switch in my „grabbelkiste“. It‘s from an old Radio Flipclock, but i think you could them as New or NOS Part.
Replacing the 3 Elcos from the Power section should be a Good idea.

Good luck
Regards Tim
 
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Unfortunately, I think I made things worse. Removed the switch completely and connected the wires together, and it's now running at 66 rpm! Something must have came loose.

It is still outputting 17.5V , didn't manage to the check the negative voltage yet. The zener diode reference is still 5V though. Sigh.
 
The higher Speed is ok, when the 3 way selector is in off postion and you connected the white wires together. It is the unregulated Max Speed of the Motor.
What happend if you then select 33 or 45? The Motor should run with different Speed.
Could you confirm this behavior?

The Pins with the blue and red cable are Good Points to messure the 18 V and -5 V against the Pin with the black cable ( ground).
 
Hi Tim,

33rpm selector is now 66rpm while 45rpm selector is close to 80rpm. I must have knocked something loose as previously 33rpm selector was 46rpm while 45rpm selector was 66 rpm. Thanks for the tips for the blue and red pins.

I can confirm 17.8V and -4.9V from the power board.
 
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So that’s nice. Keep the white cable connected together until you habe a New switch! If i remember correctly, you replaced the two adjustable resistors on the motor board. Therefore you Need to adjust them First. So set the two Speed controls next to the 3-way switch to the middle postition. Then adjust the Speed on the Motor Board . Start with the 45 First. If That fits roughly adjust the 33 regulator resistor. Then recheck the 45 Speed. If that fits you could finetune the Speed with the pitch potentiometers and the strobe Lamp of the Player . Keep Fingers Crossed
 
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