[sdiy] technics 1200 - backwards

[Atom 'Smasher']

cross-posted

this has been asked on the circuit-benders list, but i think it's of
interest to the DH and DIY crowd as well.

this was tested on an SL-1200mkII, but should work the same on the
SL-1200mk3 and the 1210 (black) versions, too.

to make a 1200 spin backwards, remove the cover, underneath the
platter: find IC101 (AN6675) which has a heat-sink on top of it.

wire up pin #8, through a SPST switch, to ground. (a good ground happens
to be the jumper, next to pins 12-13 of IC101)

if the switch is open, the platter spins forward, as normal. if the switch
is closed (and pin #8 is grounded), the platter spins backwards.

where you put the switch is your problem.... it looks like there is a good
spot between the pitch-fader and the platter. i'm gonna use a panel-mount
push-button switch that mounts in a round hole. if you come up with
something better, let us know. make sure you remove the HARD plastic
bottom from the metal upper-housing, and locate a cavity BEFORE you drill
a hole in the upper-housing.

i was thinking that it'd be cool to use an LED lighted switch, to indicate
that the platter is in reverse mode, but the shorted-circuit (on the deck
i tested this on) only pulls 0.28 mA, not nearly enough to light up an LED
by itself. if someone is really motivated, they can use a DPST lighted
switch (and wire up an LED), so one of the poles controls an LED.


        ...atom

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