Sony CDP-CE535 Discs Wont Play

So I've got this CD changer that we've had for atleast 20 years, hasn't been used much in the last 10 years, the last time It was used it worked perfectly.

Sat for a while until I tried to use it about a month ago and it doesn't want to play the discs. It will acknowledge that there's discs in the tray but when time comes to play it never reads the tracks on any of the discs.

You can hear the motor just speeding up and slowing down for the cd drive and the lens for the laser moves in and out. It'll stay like this and nothing ever plays.

So I thought to myself it's the Laser, KSS-213B so I replaced it with a new one (yes i desoldered the safety jumper) and it does the exact same thing! Im lost as to what could be the problem here.

See Youtube link.

 
Loose belt sometimes...if the laser is trying to locate the tracks, may be electronic fault elsewhere.
Tedious work, as the old and new lasers did not work.
Check the wires to the rest of the unit for connection integrity, and the power supply voltages.