Technics SL-1200 MK2 with erractic speed (and blinking lights)

Hello,
Everything worked perfectly until one day when I turned on my pop-up light. Suddenly, the player began to run irregularly and both the stroboscope (on/off-button) and the pop-up-light began to flash. I have examined the lamp, there are no short circuits.

It flashes only when it plays (the disc spins). Whan just on, it has a steady light. There is also a clicking sound when it spins. Only off the engine. Not when I roll it manually.

Luckily I have another SL-1200 MK2 so I have tried to connect that player's three contacts to my player with errors. Pitch control, lamp and (off / on, 33/45 / start / stop) parts are in other words ok.

I have also replaced the IC101 (motor circuit). Yes, I now have one for sale if anyone wants to buy 🙂 I have also changed diode 103 (now 4.7V 500 mW) and resistor 307 (now 10 kohm 0.25 W) which many suggest in various forums.

I have also soldered the contacts in the tone arm.

What do you think is wrong? What should I change / do?
 

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Replace the platter on the spindle and see if the behavior repeats.

The motor should absolutely, positively NOT be run without the platter in place. Hopefully you have not damaged anything, but do not be surprised if you have.
 
Hi 6L6,
Thank's for taking part in my problem. I'm sure there is a solution för my problem. If I understand you, you want me to test it without my platter. It's the same issue. Take a look at my attached video.

At first I thought it was the powersupply but when testing it through my other playes on/off button (I just changed the connector 201). The error was still there.

Or did I just tested the buttons when changing the connector 201??
 
Hi,
I See. In the service manual Technics wants me to take a look at the values both with the motor on and off and that is impossible with the platter on.

The case is closed, thanks for all your answears.

By the way, the engine still works ;-)