[G6ONEDave]

Glad you got it mostly sorted. The cartridges can be sourced on eBay along with stylii. However if you originally had ceramic types and the decks are good enough, you could upgrade to magnetic type but you will need to add a pre-amp to increase the output level from the magnetic cartridge. If you do go for the magnetic upgrade, the DJ favourite would be a Stanton cartridge. They also have the name 'Pickering', essentially the same cartridge except that the Stanton is a little more robust, hence why they are used for disco consoles. BTW you might be lucky in that the mixer may have a choice of phono inputs for either cartridge type. The type of cartridge mount is probably 0.5", which is the distance between the mounting screws. Changing the cartridges is fairly straightforward but a bit fiddly, needing some patience and a steady hand. Replacement push on contacts for the cartridges often come with a new cartridge but can be tracked down if not. If you do this upgrade, remember to adjust the anti skate and balance weight at the rear of the tone arm. If the decks are idler drive you are probably best staying with ceramic cartridge, magnetic carts are better on a belt drive deck.