Fehlmann Picomax 100 Retrofit

I should have an usb oscilloscope somewhere. But I last used it three relocations ago, so I have no clue where to search.
But the DSO-Shell things look quite handy.

found it totally forgot that it was also an 8 channel logic analyzer

It ha nos software which runs on ma current laptop. But maybe the linux software still runs

Still didn't take a look at the scales, but ordered a new Spindle Motor and drive. I hope I get some money for the old one. But changing that solves so much issues. But I guess it will take two months till its here.
Also found an extra set of glas scales for the column and got some good input from Andy how to use them for Z offset.
And the most important part it's getting warmer, so its more fun to spend some time in the shop

Saturday is shop day...
So I went to the shop to tackle the glas scales. But they're not working.
Checked another encoder and it works.
Oscilloscope doesn't help I get no signal. I found a data sheet for the glas scales, cable colors are correct BUT the lamps only draw 20-30 mA which is to low it should be 120 mA.
It would be odd if all three encoders would be defective. But having three wrong wired encoders would be too. Except it was on purpose.
So what now? Do encoders survive try and error by trying to find out how they are wired up?

What type of glass scales are this?

What model number of exe do you have?

If they have been in service the last 10/15 years, the bulbs might be have been exchanged to led. Then 20-30 mA would be ok.

I have no real history of this machine. It was kind of an impulse to buy it.
All ar Heidenhains
X axis LS 403 ML 1020 mm ID Nr 226 520 1K S.Nr 898292 A E5
Y axis LS 403 ML 470 mm ID Nr 226 520 OP S.Nr 1405525 B F6
Z axis ROD 456 5000 02S09-04 ID Nr 295 459 D.Nr. 14 165 553 A D5

To replace them would be a pain and the it might be cheaper to change the old DC servos to modern ones and don't use scales.