ZoKtorR
New Member
Hi,
My Technics SL-1411 that I bought second hand has a mysterious issue: when I turn it on, the table starts spinning by itself. Normally it shouldn't start before I hit the start/stop button. Even when cycling the return sequence, it still keeps spinning.
The weird thing is that the start/stop button acts as a brake: when I keep my finger on it, the platter slows down slowly to a full stop. Letting the button go gets it up to speed again.
I measured out the arm switch (S302), it's fine and it "clicks" at the right moment. I replaced or checked pretty much everything on the start/stop board, the IC was replaced twice. All the caps were replaced. The resistors were all good. The diodes are all good. The transistors were replaced. I checked continuity of the traces.
I'm just a novice/intermediate at these electronics parts, and the soldering, but I think I did a good job.
I wrote some pin voltages of some IC's and transistors down, if anyone would care to take a look: https://docs.google.com/spreadsheets/d/1pi5VauBiPf4Tsm4rqSHboEIkxbUMJxb7912fDlt4hOU/edit?usp=sharing
I don't know what I can do to make this thing work. Anyone have any ideas?
My Technics SL-1411 that I bought second hand has a mysterious issue: when I turn it on, the table starts spinning by itself. Normally it shouldn't start before I hit the start/stop button. Even when cycling the return sequence, it still keeps spinning.
The weird thing is that the start/stop button acts as a brake: when I keep my finger on it, the platter slows down slowly to a full stop. Letting the button go gets it up to speed again.
I measured out the arm switch (S302), it's fine and it "clicks" at the right moment. I replaced or checked pretty much everything on the start/stop board, the IC was replaced twice. All the caps were replaced. The resistors were all good. The diodes are all good. The transistors were replaced. I checked continuity of the traces.
I'm just a novice/intermediate at these electronics parts, and the soldering, but I think I did a good job.
I wrote some pin voltages of some IC's and transistors down, if anyone would care to take a look: https://docs.google.com/spreadsheets/d/1pi5VauBiPf4Tsm4rqSHboEIkxbUMJxb7912fDlt4hOU/edit?usp=sharing
I don't know what I can do to make this thing work. Anyone have any ideas?