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About the pitch calibration, I've written this text extensively already, so allow me to copy paste 
First a little explanation, it might be a problem, it might not, depends from deck to deck. Pure Logic. In fact there are two 0% points on the pitch slider... There is the quartz locked one, that is unmovable unless you tamper with the quartz system itself. That one will almost never cause a problem. But if you think logically, there is a second 0%. Let me explain. Your pitch slider goes from -8% to +8% (let's assume this is right). So if you think a little bit, there is bound to be 0% somewhere in the middle, no?
On a factory deck, and a well calibrated one, both 0% points will be superposed, you will only notice one 0%, at the point it should be.
But, on some occasions (and believe me this problem isn't so rare), there will be a slight difference on the location of both 0% points. That problem usually manifests around the quart lock (duh). I'm sure some of you guys already had the experience of you make a very fine adjustment around the click and it doesn't seem right. Like for example you are pitching up, and when looking to the strobe dots, they move backwards first. You pitch even more up, they come to a stop, and then only start moving forward (the other way around is true also). This problem gets worse if you tweak the pitch range, as you expand the scale, the problem will expand also.
How to calibrate? Well first things first, if you want the real 8% scale, like I said on most TT's it will still fluctuate. So what most repairers do (I had to repair/calibrate Techs when I worked in an electronics/dj shop), is use the +6% dots as reference. Those little dots should seem to stand dead still on +6%. Using those dots to calibrate will ensure you you'll have about the 8% pitch scale, close enough. So first let's try to set the pitch scale so it behaves right at +6%. For that you use that blue pot on the PCB under the platter with pitch written near it, called VR301. If you wanna set it to "factory default" you'll need a frequency counter. The default value is 262.08 kHz. Most of you don't have this, but you don't need it. You just want to adjust it until the +6% dots stand still on +6%. Be as acurate as possible. You may notice that the -3.3% dots and +3.3% dots don't really stand still at their respective speeds then, that's the fluctuations I talked about, nothing to worry about, it's normal on most decks.
Of course some people will already have this setting, but I must admit most new Techs I saw had a slight drift. The better for you if it's good already for you.
After you done that tweak check around the quartz lock. Go from a negative pitch value to a positive pitch value in a slow, smooth motion, while looking at the large strobe dots.
Ideally they should move backwards at first, smoothly go to a full stop, and then smoothly speed up. SMOOTHLY. If they stop two times (the second zero problem) or stop for a long time and then have a pretty jerky speed jump, you'll have to tweak another potentiometer, but this one is at the bottom side of the pitch PCB.
To reach that one, secure or remove all loose parts (tonearm, adaptor, needle). Place your TT upside down on a pillow. Remove all the 21 screws on the bottom (those placed in two concentric circles, so not those around the rca wiring) and the 4 feet. Then gently remove the rubber base.
Once you've done that, search for the underside of the pitch slider. On that circuit board you'll notice a little hole. Through that hole you can adjust that pot, VR302. This is the one that will adjust the center pitch, so basically that second 0%.The factory default is 2.7 kOhms (measure with a multimeter), but I've found a value of 3.25 is usually better. Every TT is different (resistors are rarely perfect), but I find the right settings are usually around that 3.25 .
Anyway, if you don't have a multimeter, it's trial and error time. Tweak, turn around and test (you don't have to put the bottom back each time), if it's not good, tweak again, test... Until you found the best setting.
If you tweaked it, it's always safe to check if the +6% setting you did before is still right, it might have changed when you adjusted the position of the 0%. If it changed, adjust until it's right again, and check back. Once you did this, your pitch is calibrated as good as it can.
While we are at it, you may have noticed that near the pitch scale potentiometer is another pot with BRAKE written next to it. I wonder what that one is for
Again optimally, the platter should stop dead in an angle between 90 and 120 degrees. I said dead stop. Not having a fast brake and then slowly running out, or having such brake it stops and starts turning back again. Dead stop. Try this with several records on the platter, with the needle on different spots, 33/45 RPM, different pitch settings. All those settings will have some minor effect on the brake. But you should aim at a setting where 7 times out of 10 (at least) it stops dead on any setting.
As for the quartz lock... Do you want to completely remove it or to make a m3D quartz lock defeat button mod? Different things.
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