Mitsubishi FX 20 - system loading problem

Hi,
I have problem with FX20, after the battery inside cabinet was dischared and the system was out, I tried to reload system.
When I insert 1st system disk and press input, endless loading happen. I have emulator with system disk images, the same thing happend, the emulator have LCD with information about track and side, it goes to 45 track/ side 0 and nothing happen.

I borrowed 2 modules inside CNC system (416D and 116) - 416D is the one with small battery inside and connected to FDD. The PCBs weren't used few years.
In this case, 1st and 2nd system disk is loaded properly but on 3rd disk the same situation happend, endless loading.

Do you have any ideas how to fix it? Maybe one of the eprom is wrong? Or the problem is with SRAM memory?

Best regards
satsun

Was this 3rd disk endless loading with emulator or did you go back to floppies ?

You are on the right track changing out the mw416 and 116 boards. Do You have Mits support? Just curious how you identified these boards

Both, floopies and emulator, the same situation.
Yes, serviceman from another country told to change it.
One man told that in some of meldas numerical controls have self memory check, anybody knows how to do it?
Maybe someone have some docs about LEDs on this boards?
As far as I know, LEDs look ok. Both PCB the same.

Problem solved, one IC damaged on 416D PCB.

Thanks for updating this. Good to know.