X68000 Pro HD that doesn't boot :(

[mirtolone]

Hello,
i'm an owner of a X68000 Pro HD with SASI HD and 1mb (?) expansion and i've a problem:
The machine seems not to boot anymore. I've bought it from Japan many years ago and it was fully functional (i'm italian, i used it connected to a 220v to 110v converter and a normale VGA monitor). All goes well, when a day, when to turn on it, it doesn't nothing. From that day there are passed many years and having a bit 'of time and with renewed interest I tried to turn it on.
Connecting it to the socket, the LED lights up red in the lower right corner, pressing the power button changes to green, the power supply fan runs, as well as the hd spinning and the floppy disk drive (eject buttons also work) , but does nothing. No video, no reading from the HD or FD. If i press the power button to turn off, it remains powered (also the FD drives) only change the status led from green to off.
I tried to make a new power supply with the schematics that are on the net using an ATX power supply (and the small chip and circuit resistance) but the result does not change, although connecting this everything is  the same.
With a PC technician we have seen that power is OK (all signals arrive to the motherboard) and have not noticed anything abnormal on the motherboard (except the battery removed near the power button, which should not affect the operation, among other things it has been removed after it has stopped working years ago).
At this point I don't know what else to look to understand what the problem is.
I'm sorry, because it is very difficult to find another X68000 (especially if it works) as well as expensive and with waiting long times for receiving the product.

[eidis]

 Hi Mirtolone and welcome to the forum !

The first thing which you could do is replace all capacitors and check if none of the currently installed ones are leaking or if there are any eaten up traces on the motherboard due to leaking capacitors. The X68000 is very old so it is very likely that some of the capacitors are not up to their original specs anymore and are causing trouble. You could try reseating all socketed components and inner connectors as well.

P.S. You can add a battery socket in your X68000 from a donor PC motherboard and use a standard CR2032 in it.

Keep the scene alive !
Eidis

[mirtolone]

Thank you for the hint, looking the capacitors they seems ok, but i've found the it's possible to check if capacitors are ok without removing with an analog tester, so  i'll try.

[eidis]

 Don't let the looks deceive you. It is very common that faulty capacitors look ok but in fact are not up their specifications. Try to replace the ones which have 100uf or higher ratings and see if anything changes.

Keep the scene alive !
Eidis