Which old CNC controllers are best for a retrofit?

Hi,

I'm looking into buying a CNC milling machines. As I currently live Germany I'm looking at stuff that mostly has Heidenhain TNC, Phillips 424 and Deckel Dialog controls. Is there any considerable difference in retrofitting these systems? Like for example if I get a Heidenhain TNC 355 will it be harder or easier to retrofit than for example one of the Maho E2 machines or a Deckel Dialog machine? Or maybe there is some kind of a list of CNC controls that are more or less easily replaceable by LinuxCNC?

I know that there are certain mechanical differences like for example some machines have a gearbox that is changed electronically, some have VFD, not all of the machines have true 3D capabilities (like older Mahos or some version of Deckels) etc, so I'm asking mostly about the machines that are already cabable mechanically. And the idea would be to leave untouched as much stuff as possible. Ie. I know I could remove all of the scales, servos and other things and replace them with newer hardware, but I'd like to minimize that.

As you will throw away the control, there is no difference in retrofitting the machine you mentioned. On all machines it is possible to maintain the scales and Servos and servocontolers. You just need different hardware (best would be Mesa cards) depending on the type of servo controller and the amount of io needed. Ie a Deckel fp3 with tool changer will require a. Lot of io for the changer and a mechanical gear box is more problematic in connection compared to a vfd.

Norbert