I have a sl-1200mk2 technics turn table the cartridge is old they use to be Stanton 500 stylus. I hope that you can suggest a replacement head shell and cartridge other that technics?

From the images I have seen most makes of cartridge will fit. It's a question of how much you want to pay. Stanton are a good brand.

No it's either the stylus or the pressure to the stylus is not enough. The weight at the end of the arm will increase the pressure on the stylus. Turn it up in slightly testing a record till the stylus tracks in the grooves. The trick is to get it so that it stays in the groove without creating a rumble sound. Remember though a worn stylus will not track at all.
Most cartridges track at 2 to 3 grams. If the Weight on the arm has numbers they will correspond to the weight in grams. If you have to raise it very high the stylus is too worn.

I'd fix the tonearm issue first before using it to decide you have a feedback-related issue with one brand of cartridge. I can't say how that would be fixed.

Feedback? Like airborne sounds from the speakers vibrating the turntable and being amplified through the speakers? The biggest downside to old-school vinyl use is that possibility and the workarounds we had to use to prevent it. Acoustic and physical isolation are the only solutions.

That turntable, like many others, has an S-shaped tonearm with a removeable headshell. You can use any standard screw-mount cartridge as a replacement. Which one you buy depends on what you want to spend and your intended use. If you're a DJ you'll need a more rugged cartridge than you do for listening at home, for instance.

One company I buy lots of parts from is Parts Express. Here's a link to their styli/cartridges pages. If you have the original cartridge and stylus, you can check if they have the exact replacement. Otherwise you can browse the other choices. You can find many other sources as well, and you may have an audio shop or musician's store in your area who stock cartridges.

it could be two things:
1.the tone arm wires that connect to the head shell (blue-red-green-white i think)
2. the needle arm has twisted round
Put it on the other deck if you've got one & see if it does it.
look right at the end of the needle tip,& see if it's straight & pointing down, if not carefully twist the needle arm round until it is,& push it into back in to the cartridge a little bit.

If your left technics sounds good, maybe the problem is the cartridge. Try to interchange the cartridges, right table cartridge by the left one, and listen. If now the bad sound comes from the left table, it´s time to get a new cartridge or stylus. If the problem continues there is something else to look for. Hope this will help. Flavio/Brazil.

Check the wiers on the head shell ,even concordes e.t.c.. have them,there just hidden inside the shell .just be cearefull when pulling off the end .
then try checking the phono leads that come out of the deck.
Infact i,ve got a fuew idears what it could be but you'll need to contact me coz it will take me ages to type them, this laptops got half the keys missing. TELL 07970306952

See what type of cartridge is installed in the arm. Manufacturers use common cartridges in turntables, such as Stanton, Shure etc. Detach the head shell from the arm (it usually slips right off via a locking ring and four-pin mini plug) Look for the manufacturer and model number on the cartridge. No need to remove it from the head shell. On most modern cartridges, the stylus (as they are called, rather than the needle) simply slips off and on. No need to remove the entire cartridge (via screws) and re-align it. In fact, many DJs bring a set spare cartridges and styli on a gig, already mounted in head shells, and simply interchange them as needed. When you have the make and model of the cartridge, go to Radio Shack or use their website to order a new one...or  two. Or go to Google and enter "phono stylus" as your search term. You will find reasonably priced styli for nearly every cartridge imaginable. I operate 50 year-old turntables and am able to find replacement cartridges and styli on line. Ebay also has a number of listings, by make and model of the cartridge. When the new stylus arrives, observe how easily the old one comes out of the cartridge- usually pull and slide - and slide the new one in. Re-insert the head shell on the arm, tighten the locking ring, and you're good to spin!

yah ofcourse  you replace a new one at www.turntablelab.com

This does happen. The RCA cables used on the Technics 1200's aren't of the greatest quality, and you will find lower output on some turntables. This can become an issue, if you record your sets to your PC, or you use Serato, Final Scratch, or any of the digital control set ups. There is only 1 way to resolve this, and that's to switch out the RCA cables on both turntables, and ensure that they are matched. This can be done by any qualified audio service technician. Just make sure you choose some good quality RCA cables, and not the standard OEM Technics cables.