Hi to all,

i'm a computer collector from 1998 and in my collection i have this rare computer of Olivetti Ivrea model M200. This is a very not common computer, the mainboard is subdivided in 3 separated board, one is a floppy control board with bios primary ROM and video section, one for 2 ISA 8 bit slot and an ipotetical IDE connector and IDE Boot ROM installed in proximity of ISA 8bit Slot, and power connector, and one with control port and timers.

I have repaired power supply with lacked capacitor in secondary section and the computer power on normally with hdd disconnected from board, keyboard leds blink first time at power on and second time during post, and boot from floppy with dos 3.30 normally.
During post i see al diagnostick check, the last one is a floppy seek then start boot, but i don't see any row regarding hdd drive. The hdd led blink continuosly (hdd disconnected from board) I reopened the computer and removed hdd from place and checked it, the heads blocked on the disk plate, then i have sblocked heads and now disk spin up but heads dont move. Another check on the hdd board and i have found a smaller resistor of 1 ohm in the 12volt line power for head stepper motor opened, replaced it and now the heads move to seek when the drive powered and spin disk and the led stay on during seek then going to off.

The HDD is a Miniscribe M8425XT IDE (not MFM dual connector).

But now the problem is this, when i connect the disk to the motherboard the computer not post anything, stay with black screen and keyoard blink one time when power on but no post on screen! This only with disk connected.
I have tested other old IDE disk on this computer but the problem is the same, inverted flat cable causing disk to not spin. Then i have tested the Miniscribe on another old computer board Pentium 1 and i have the same problem in it, not post not boot nothing on screen.

I have tryed to install an WD ISA 8bit MFM controller in ISA 8bit slot without hdd connected, but the computer have the same problem on power up, not post, not boot with only controller inserted, i have tested two different ISA controller, one with BIOS ROM on board and one without, then in proximity of original HDU rom i have founded jumper to exclude this rom to load in memory when boot, but nothing...same problem.

Now online i don't find anything of this machine, not manual, service manual, technical manual, jumper settings, nothing! I don't know if this computer is an XT or AT (the keyboard is an XT type), i don't know if this hdd is an IDE or XTIDE type, the connector have a forced plug way at the bottom of connector otherwise normal IDE have on the top this forcing plug way.

Then, the board with the HDU ROM have this 27C128 rom inserted in a socket, i have possibility to replace this ROM with XTIDE ROM?

Anyone have notice for this computer, manual anithing?

Help me please.