I would consider getting a new laser only get one installed by a pro like Spedmetal or someone with experience swaping, adjusting lasers. Do not just buy one and swap it out without using a multimeter and checking the pots first. If your in the US contact Spedmetal at
www.norcalmods.com. If in the UK pm Lufcfan, He may know someone who can help you out. Good luck with it.