Ever finish setting up the turntable set at your gig, firing up the laptop, and then boom no signal or you start hearing white noise trying to say “I am totally messing up your set”. Most likely you start in 5 minutes, and your checking connections, and settings like the a time bomb waiting to explode! Yea it happens to all of us. (Happened to me on Friday, and I had to spin on one turntable -_-)
There are two common issues with the Technics 1200 over the course of age. The RCA wire has some sort of internal break, or the ground you depend on to run interfaces such as Serato, or Tractor is totally not working. So today I will help you address this issue by creating this handy tutorial on how to replace the RCA cables, and self grounding the Technics ground wire, so you never have to struggle with securing the ground on the back of the mixer! You can also check out the YouTube Video I have up, for better explanation, and step by step instructions. [youtube=http://youtu.be/0WLtOYHRXm0]
Before anything let me post this disclaimer….
***THIS IS NOT A OFFICIAL GUIDE, DOING THIS MAY VOID WARRANTY, OR DAMAGE COMPONENTS OF YOUR PROPERTY. THIS IS A MODIFICATION. I DO NOT HOLD RESPONSIBILITY FOR IMPROPER INSTALLATION, DAMAGES, OR INJURY THAT MAY BE INFLICTED TO THE PERSONS PERFORMING THIS MODIFICATION.***
Now lets get started.
1.Unplug and take off all the necessary items on the top of the turntable. Vinyl, the platter, needle, and secure the tonearm.
2. Install a turntable cover (Yes that clear cover that your suppose to have somewhere) or find a way to keep the turntable from crushing the tone arm when we flip this bad girl over.
3. Turn the 1200 over, and remove the feet to expose 4 screws. There are a total of 21 Screws. 4 Long (Under feet), 6 Medium (not on the platter area), and 11 (Small) Screws within the circle. Remove all of them.
4. Remove back molding (it should peel right off, but be careful just in case you miss a screw)
5. Locate the RCA & Ground cables, and trace them to the corner section of the 1200. Remove the plastic wire hold down, and the metal plate. 2 Long screws going to the hold down, and 2 smaller screws for the metal plate.
6. Remove the metal plates to expose the audio circuit.
7. Notice the wire set up. from left to right you have white ground, white signal, red signal, red ground. These are the items that we must remove.
8. Cut the zip tie holding the wires. Use your soldering gun and heat up the existing solder joints to remove the wires. Be careful not to burn the circuit board.
9.After removing the wires, clean area with electrical cleaner, and let dry accordingly.
10. Locate the ground wire (to the mixer) and strip the end of this wire.
11. Grab your new RCA cables, and cut the end connections at their bases. Inside the wire are two layers of rubber. One is the outer portion that seals the ground side of the circuit, and the inner is the signal wire.
12. Use wire strippers to expose the outer ground wire, and gather the wires together, and twist them. Make sure to get all strands of the ground wiring.
13. Use the wire strippers to expose the signal wire, and twist wire to hold the strands together. (It is IMPORTANT not to have a ground and signal wire to touch each other. This can cause bad interference, or (on a highly unlikely scenario) a short in the circuit SO PLEASE DOUBLE CHECK YOUR WORK!) Do this to both red and white circuits.
14. At this point create a L shape with ground wires protruding out, and signal wires straight.
15. Trace your wires to make sure you are starting from the red side of the circuit. Place the wires on top of the solder points of the red circuit.
16. With your solder gun melt the existing solder points, and secure the connections to the points.
17.Take your white wire, and the ground wire from the 1200. Twist the ground wire from the 1200, and the ground wire from the white RCA together. (Before doing this I suggest tying the extra ground cable together with a zip tie). This will ground the ground wire to the ground of the white signal.
18. Repeating the steps from the red circuit, solder the wires onto the circuit board.
19. Your finish product should look like this.
20. Secure the wiring with another zip tie, and re install items in reverse order. Before installing all the screws to the backing, make sure you plug in your turntable, and check for proper operation through your interface. (ie. Checking Serato check ground ring on settings). If the settings pass then finish installing remainder of screws on molding.
There you go! Now all you gotta do is just hook up the RCA cables to the interface hardware, and your set! No more trying to get that ground cable to the mixer! One less step to setting up, and less wires!
If for some reason you are not getting a good ground or audio output, then there may be a couple issues. This can be due to a signal wire and ground wire crossing somewhere (double check your work). If your work checks out, then there may be an issue with the circuit board, or a grounding issue located deeper into the turntable.
Now get back to dj’in! Make sure to visit my web-portal at www.MarkyG.me , Follow me on Twitter & Instagram @DjMarkyG , and give me a like on my fb page here!
(Dj Marky G)
wow thats a lot of work, good work!
Why would they NOT do this when they originally produced the 1200?
I am also wondering about this… There must be a reason they made separate grounding
The reason is technical.
All “grounds” are not the same. In this manual, you are tying the ground for the audio circuitry to the chassis ground.
When we measure voltage we measure it in reference to ground, meaning that 5 volts is 5 volts when compared to ground. When you tie these grounds together it is possible (and likely) you have changed the ground. Now instead of 5 volts you get 4.8 volts (or whatever) because you have changed the difference of potential by creating a common ground. Now all of the audio circuitry is behaving in a different manner.
The reason the ground wire exists at all is because we WANT to tie CERTAIN grounds together to create a common reference point. When you connect the ground wire to your amplifier/preamplifier/mixer/whatever we can be sure that the audio circuitry is working from a common reference point.
Did get I it right that you just removed the earth wire?
The earth wire was not removed. The wire was circuited to a different ground source.
Ah ok now I see because in later steps I don’t see the connection of the earth wire to the ground terminal anymore. Did you try to connect the earth wire to both ground terminals?
On step 17 I put the ground wire with the white RCA ground. This is all the ground the turn table needs. If you need better instructions please watch the videos to visually see what I did.