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-   -   Technics 1200 MKII 3D - Quartz Mod help (http://www.wavemusic.com/community/showthread.php?t=13904)

herbalpudding 09-18-2013 12:08 PM

Technics 1200 MKII 3D - Quartz Mod help
 
I know this has been covered on the forum in the past, but I was hoping to get some definitive answers around modifying the quartz compensation on my SL1200 MKII 3D turntables.

This thread proved to have a lot of great information:
http://www.wavemusic.com/community/s...ead.php?t=2674

But it gets confusing as to which mods apply to which models of Technics, and which problems this mod is actually solving. So I am going to try to lay out my questions here in a logical manner.

OBJECTIVE:
I want my Technics to do less over-compensating when I manually slow down the platter by hand. Specifically, I want to minimize the pitch change that occurs immediately after I release contact with the platter -- the platter speeds up to return to the locked-in pitch position as quickly as possible, then slows down to lock itself into that correct speed so that it doesn't speed past it. (i.e. "speed up to slow down effect")

WHAT I DON'T CARE about:
Removing the "center click" or "green light" for older models of Technics. I got lucky when I was young and stupid and bought the M3D with the separate pitch lock button and no center click, even though the manuals were in Japanese! Smart move! I don't need to deal with any ball bearings here.

QUESTIONS:

- I know I need to clip one end from resistor TP17 (also known as R209). Is this all that I need to do?

- There is a lot of talk about snipping the orange wire on the pitch board. Does this only apply to Technics with the center click problem?

- Has anyone had any lasting problems or repercussions from performing this mod?


Thanks for your help. I am hoping that the clarity of this post will help others in the future as well.

-Ben

Balaroue 09-18-2013 12:39 PM

I had the mod done years ago, works perfect. While I always just assumed it reduced the torque, I'm told it's actually disabling the Phase Lock Loop (PLL).

herbalpudding 09-18-2013 01:49 PM

Yes, I too had read that it might be more about the PLL rather than the quartz lock. Thanks for sharing.

Can you add any clarity as to what you did to yours? Do I need to do anything other than clip TP17? Did you snip the orange wire too or add any other resistors?

Richi 09-18-2013 11:06 PM

TP17, R209 (330K Resistor) is connected to pin 14 on the IC AN6680. The block diagram of the AN6680 shows that Pin 14 is the phase control. So lifting one end R209 is affecting the phase control logic.

AN6680 is applicable to both MK2 & MK3, so lifting R209 should be sufficient for the mod.


Panotaker 09-20-2013 01:54 PM

I'm the guy who wrote this article on the quartz lock mod

http://www.new-line.nl/?i=62

The article explains what the mod does in detail, and exactly how to do it and undo it. The mod works on all versions of the 1200 except for the m5g. I do it to all my 1200's and never had any problems. If you got any questions, let me know.


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