Technics 1210 mk2 pitch fader fix (and instructions on its removal)

[dantheman91]

Hi


is the pitch fader an easy fix. i have been offered one of these for £60 is it worth it.

Dan

[Dingdong]

Do you really need it? You could always wire it out. There is a pot inside I believe to set the speed right.

[dantheman91]

Hi

no i wouldnt need it. but the owner says it now running a constently at a fast speed. would it be easy to wire it out?

dan

[Dingdong]

I think so. Somebody with some experience of the innards should be able to instruct you.

[Beobloke]

Easy to wire it out, even easier to replace it. £60 is a no-brainer - go for it!

[Bwaze]

I have removed it since I will not use it, and it was in a bad shape anyway.

I read the instructions somewhere in a long forum topic, can't find it now, but it's very easy. You disconnect "pitch connector" from the main board:



And then you connect the two middle connections on the main board pitch connector. That has the same effect as pitch control in the middle position (which bypasses pitch slider). You can use the "jumper" from a PC motherboard if you don't want to solder around main board.

I don't know if any of the wires from the main board to the pitch board connects the grounding, or is the ground carried through the chassis? Best to ground the main board from a proper position:



This shows the back side of main board, if viewed from above the ground is under bottom left screw.

[Dingdong]

Is it running a little bit fast, or a lot fast?
Does the fader thingy make any difference to the speed?
I have just had a look at the service manual and it should be able to adjust the pitch with VR301 on the pcb.
Hopefully someone with experience of doing that will pop along soon.

[Marco]

Hi Blaz,

Excuse my hard of thinking, but could you explain what you mean by:

And then you connect the two middle connections on the main board pitch connector.

Where are the two "middle connections" you're referring to? And also, if you could show exactly how one "grounds the main board from a proper position", should this be necessary.

Some nice arrows on pictures pointing to exactly what you're talking about, in the form of a step-by-step guide, would be great - cheers!

Marco.

[Bwaze]

Sorry for my unclear English, not my native tongue. Also I'm not an electrician, I'm just following the propositions made by others. I'll try to be more clear this time, and try to find the sources for the claims. And sorry, no step by step picture book, I'm not dismantling my 1200 now, still waiting for a few parts before I install the new "Mains Cables 'R' Us" PSU and KAB fluid damper.


Technics SL1200 MkII main board, with pitch control bypass and proper earth point described:



I followed the "thedelihaus's" advice from Audiokarma forum about removing pitch control:

Regarding the pitch control- you can remove and bypass it- unplug the connection of the pitch control wires/plugs and join the 2 center pins of the socket together.

- Connecting the pins 6 and 7 has the same effect as placing pitch control in the centre detent, which is a switch that bypasses the potentiometer.

Here's the diagram of the pitch control PCB from Technics SL1200 MkII Technical Service manual, Supplement, page 21 :



As far as I can see earth cable that connects to the pitch control PCB screw only connects to the main board earth through a conductive chassis, and that is not optimal - coating and oxidation can even prevent the connection. So I think it would be better to connect it to the proper earth wire tag on the bottom left of the main board - extend the earth cable and solder it to the underneath of PCB. Link to the explanation why this is the proper point to earth the Technics: The final Words and Music on the earth point.

Not as clear as I hoped it would be, but it will have to do for now.

[Marco]

Hi Blaz,

That's spot on, mate. I understand exactly now, and many thanks for taking the time and effort to explain things properly! It'll act as an excellent reference point for others wishing to do the same

What did you find was the best (neatest) way of joining the two centre pins, and did you notice any sonic improvement after you did the mod?

Marco.