Instrument replacement. Preventive maintenance?

I've read through the regs many times but I'm still unclear on this. I try to do all the preventive maintenance on my Cherokee I possibly can and I've been told by others that an owner can replace instruments. I see the rules spell out that electronics can be pulled from trays but Can an owner replace instruments on a certified aircraft including an altimeter under the rules?

I'm working on my second aircraft build so the mechanical knowledge isn't a problem.

Thanks for any insight on this.

Part 43 Appendix A does not specifically allow replacement of instruments and/or altimeters.

I agree with Marty. Instruments are not listed as Preventive Maintenance. Further, NOT all tray mounted avionics can be removed and replaced. It specifically disallows DME, autopilots, and Transponders.