First, welcome to AK - nice to have another Tandberg owner visit.
Second, there's a specific forum to post manual requests: Digital Docs.
Third, don't bother - I don't know of anyone that has a copy of that 3015A service manual, if one ever existed. I've been looking for one for years myself, as have many other Tandberg enthusiasts.
The 3015A is basically a Philips CD150 in terms of the optical pickup and digital board. The power supply has been beefed up, and the opamp analog output of the Philips is replaced by an entire analog audio board that occupies the right hand side of the player. It has an all-discrete class A circuit design not to mention a dedicated headphone amp, and is therefore quite a bit better sounding than the stock Philips design.
In terms of service, you can use the CD150 service manual for reference on all things associated with the digital part of the design.
I have some rough copies of the schematic for the analog audio board. You can PM me for copies of those, and of the Philips manual. I think I also have some PCB layout diagrams for the digital section.
We have at least one expert vintage CD tech here on AK that knows this player (and Philips-based players in general) very well, so I would suggest you may want to post some details of the issues you're experiencing.
John