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24th Jul 2005, 10:45am

Adjusting pitch control for technics SL1200

[This is cribbed from a message board, I wanted to keep it for reference. It's about adjusting the 0 mark on the pitch control so there is not a second 0 point away from the central indent.]

You can fix this quite easily. i have done it on about 8 decks and am getting much quicker. takes about 30mins now. but to the beginner, expect it to take about an hour.

firstly you should know how to pull apart your technics.

NEVER EVER TURN THE TABLE ON UNLESS THE PLATTER IS PROPERLY INSERTED!!!!!! (it will destroy the motor)

ok. now we're passed that

there are 2 controls you'll need to play with.
1. is the pitch centring pot
2. is the pitch width pot.

FIXING THE two 0%'s:

the reason your table appears to have two 0%'s is because the pitch centre is not calibrated correctly. this is simple to fix, you'll need a multimeter (that can read kOhm) and a philips head screwdriver and a small adjusting screw driver.

firstly pull off the platter (if its really tight, grip the platter while a friend gently taps the centre pole thing that goes thru a record..)
pop it comes off...

remove the black cover that was under the platter. there's about 5-6 screws (can't remember). probably worth noting that there's going to be a lot of screws, so get 5-6 different containers. you'll figure out which screws are similar as we go along so just stick em together ;-)

okay on the right hand side of the board theres a plug with four cables hanging out of it, it leads to the underside of the table towards the pitch controller. disconnect this. (it just pulls out)

OKAY.

turn the table over and we'll pull the back apart. (the 0% calibration pot is on the rear of the table)

unscrew the legs off (just grip and turn). then all the screws on the black plate (about 21). there's 3 different sorts, easily identifiable, so keep em separate.

ok, the back's off the turntable.

you'll see the green circuit board that's attached to the pitch control. on it there's a little hole right beside the pitch slider, if u look through it you'll see a screw adjustment (that's the 0% calibration pot).

With the pitch control set at 0%. connect your multimeter as follows:
red probe on the brown wire (of circuit board)
black probe on the red wire (of circuit board)

note this figure down. (if you don't have a multimeter you can still do this just expect to take a few hours to get it right...)

ok. we've got the old value, so if things f*ck up we can fix it back to that at least.

now reconnect the 4 cable plug on the up-side of the table. put the platter on. power up the table and let it spin.

adjust the pitch control until it gets back to 0% (ie the second 0% which is not the one where it should be). basically move the pitch slider until the big dot on the platter sits still (when you look at it with the red light on the power switch).

ok. now the pitch is at 0. (the wrong one... i know... but wait..). turn off the table, remove platter, remove the 4 wire plug to the pitch control board. flip the table over and re attach the multimeter.

now write out the value the multimeter's giving you. (we'll call this the NEW READING)

okay , set the pitch slider back to 0%.

(you should see that the multimeter goes back to the old reading.) using a small screwdriver adjust the pot (beside the pitch slider) until it gets realllllly close to the "new reading".

viola you've your dual 0% problem.

(it's worth checking this before you spend 20mins screwing the base back on).

so plug in the 4wire connector, put the platter on and confirm that there's only 1 x 0% spot now.

if not, fiddle with the pot until it gets better.... you'll figure it out.

(if all thats working fine, reassemble the base... but don't do the top of the table.....)

ok. Now to fix the -3.3, 0 , 3.3 and 6 pitch settings.

(just incase you didn't know.....) the 4 aluminium rings of different sized dots on the side of the platter are used to calibrate the pitch of the table.

the bottom ring should sit still at -3.3%.
the big dot should sit still at 0%
the second-from top dot should sit still at 3.3%
and the very top dot should sit still at 6%

this is the same for 33 and 45 rpm.

locate the pot on the top of the board labelled PITCH.

with the platter back on and the pitch controll connected. (but the black plate under the platter removed).

you should note that you can adjust the PITCH pot whilst the platter is on the table.. (just happens to line up through the finger sized removing holes on the platter).

basically just adjust the PITCH pot (IN THE SMALLEST INCREMENTS) until you can get the -3.3, 0, 3.3 and 6% speed dots close.

this takes about 6-7 goes to get it right, but it's worth it.

[by dj esscue]

Extra tech note: x201 is 4.193 MHz