Technics 1210 internal regulation mods

[Paul Hynes]

Hi Andy,

The drill holes shown will be correct. You can follow Martin T’s or Mike N’s instruction if you prefer. I prefer to drill the holes as shown in my instructions so the wire can then pass through the board and be soldered to the required point. Passing the wire through the board provides a firm anchor for the wire should you want to remove the board for further work in future. This should avoid damage to the solder joint or lifting of pads and tracks that could occur if you just take the wire under the board and solder to a pad.

Regards
Paul

[Wakefield Turntables]

Paul, Martin, many thanks guys, I think I'm off down the drilling route, I've cut the wires now and I have the gear in the garage so it's daft not to! I'll keep you all posted.

[Mike_New]

Andrew,
The locations are correct. As with Martin my advice would be not to drill the holes. The single reason for this: If the drill slips or you go through the PCB to quickly you are likely to damage the board. If you must drill holes then place a piece of tubing onto the drill so that only 5mm of the business end of the drill is showing when tightly gripped in the chuck. If you have a small 'Dremel' tool then hole drilling can be more controlled.
I would reccomend my approach for the simple reason that most people here are not completely experienced in handling tools and doing work of this kind in what is a very confined space for drilling.

[Paul Hynes]

Mike,

You are right about the potential for damage. This can happen just as easily with incorrect wiring. When doing modification work it would be better to have some general DIY experience. If people are not comfortable with DIY procedures on their SL1200 they should seek the help of either someone who is, or a professional who is prepared to do the work for them.

I am working on a solution for this at present and will be providing details shortly.

[Wakefield Turntables]

Drilled the holes last night as easy as you like! I've gone down the 1.5mm silver route as that's what I had spare in the garage, so the holes are actually two mm's. I have studied the wiring and it looks simple enough. I will probably star earth as well, just need to google a guide about how to do that. MArtin, fancy giving me a tutorial

Thanks foe the support so far guys

Andy

Ps still waiting for the bloody Teflon

[MartinT]

MArtin, fancy giving me a tutorial

Star earth? Simple - firstly, identify the central point of ground returns which in this case will be the lower-left PCB mounting post as that is where the ground tracks on the circuit all lead back to. Now connect the following direct to the same point by using wires with solder tags:

1) -ve from TDR-21 module
2) -ve from +12V module
3) -ve return from external PSU
4) green earth wire out as central turntable earth to preamp ground post
5) wire the arm earth separately to the preamp post if a non-metal mounting plate is used

Refer to my photo and you can trace them all.

Do not star earth the +5V module as Paul says a short path is critical. You can see that I've twisted +ve and -ve together and taken them to the two holes vacated by the now removed D301.

[Wakefield Turntables]

Thats amazing, many thanks. I did a couple of hours research on star earthing, seems like many version exist but I'll stick with what you've described here

[Wakefield Turntables]

Right very nearly finished the mods i have one problem and thats were to solder the 1 x 240mm wire for 0v on the underside of the PCB. Its pretty obvious to see where the wire should go under the PCB. This is the only real sticking point. Thanks in advance. I'll try and post a pciture to make the post a little clearer.

[MartinT]

If you're star earthing, the 0V returns should all go to an earth tag to fit under the screw on the lower-left post. The only exception is the +5V return, which goes to the hole vacated by the D301 diode.

[Wakefield Turntables]

I will be star earthing at some point but my thoughts are that I want to get the mods installed with the piece of mind that they work! So i guess my original question still stands, any idea where to solder the 240mm wire on the underside of the PCB?