It's 360kb low density, but a working one will work provided you get the jumper settings correct, Amstrads often used "no twist" floppy cables, where the drive ID was individually set, vs the non-standard PC standard where everything is set to second drive ID, be that 1 or 2 (some labelled 0,1,2,3, some labelled 1,2,3,4) and it's sorted out by the cable twist.

Edit: as Errius said Double Density, I keep forgetting the existance of SD single density, which was mainly a thing for CP/M systems, Apple IIs etc. My brain goes Low/High, being the lowest and highest common on PCs.

I see, thank you for the quick answer, so not the best one as far as compatible format, I suppose 5.25 compatible with high density disk will be very expensive...

That will be Sankyo with Amstrad branding. I have a pair of DFE222A10-A drives which I guess must be similar spec.

Check if your floppy drive is here
https://www.youtube.com/watch?v=VZ9xhFkHZ5c
Even if not, it may give you enough hints to make it work.
This one may be useful too
https://www.youtube.com/watch?v=fRZVlsxSDw0

thank you everyone for the tips.

Errius wrote on 2023-01-28, 19:05:

That will be Sankyo with Amstrad branding. I have a pair of DFE222A10-A drives which I guess must be similar spec.

Is it able to read 360kb floppies only?

Yes, double density, 360 KB. It won't be able to read high density disks.

A bit off topic, but I found a computer labelled MP 286H, clearly a 286, with a 5.25 floppy drive, is it possible that this one will be able to read 1,2mb 5.25 disks?
I'm really unaware of 5.25 drives (or disks) since due to my age my first pc was a 386 with only a 3.5 floppy drive.

This is the pc:

A 286 will almost certainly have a high density (1.2 MB) drive, but you should check with the seller to make sure.

Errius wrote on 2023-01-29, 02:16:

A 286 will almost certainly have a high density (1.2 MB) drive, but you should check with the seller to make sure.

I doubt the seller is willing to share any info, he is selling the pc as it is...
The price is the same as if I would buy a 5.25 floppy drive only, though...
I hope it won't be a bad deal, I noticed that the floppy drive has a cardboard inside the drive, so it should have been kept properly?

Yes the cardboard is there to stop the heads banging into each other when the machine is moved. It's a good sign, but you can never be sure with things like this.

Good luck with the purchase.

Bump, I got the pc, how should I proceed?
Check if battery leaked (but I doubt I noticed it had a 3 battery holder instead of the barrel leaking battery, also how can I check the psu in case it went bad?
Should I connect it with just an hard drive connected? Maybe one I can sacrifice? Or can I use a floppy 3 1/2 drive?

Picture:

When I receive a computer like this, the first thing I do is completely disassemble it while carefully photographing everything. Clean dust, check for damage (burned components, etc). Also look inside the PSU. Blow some canned air over everything.

Then partially reassemble it. Just motherboard, PSU and video card. If it powers on OK, reconnect the other things.

I measured the value from a molex cable (after disconnecting the 5.25 floppy drive (the thing I care most):
5v : v5,05
12v: v11,97
The inside was moderately clean already but I got worried from the dimension of the cards installed.

There is a more pressing problem now.
I can't test the pc because it doesn't has a vga compatible video card?

Any suggestion? Try to plug an isa card?

You might have CGA composite there. However, that's not super easy to deal with in Europe, I synched it before on monochrome security monitors that had a lot of vertical hold adjustment. Might get mono synched on Amiga, CPC464 or Atari monitors with vertical hold fiddling, or if you have a TV model that was sold worldwide, luck out and have it recognise the NTSC color encoding.

Do you have any ISA VGA cards?

I took off the 5.25 drive it's a JVC SS01GF 360rpm. I didn't find any info about it.

That's for the 5.25 floppy drive, about the pc:
The motherboard is a suntac but the layout is different from what I find there.
I tried to set the hard drive as mode 6.
That's a paper who was around in the case:

Connected a surely working floppy drive 3.5 1.4mb, everything is detected but as soon it end posting there is just a blinking cursor, missing operating system or the error in the next post.
I don't know if the hard drive is broken or bios settings are wrong, without floppy disk I get the error of operative system missing.

I don't know but i'm not so sure that every switch on the motherboard should be on

That's what I get if I boot from my floppy drive and disk 1 of ms-dos 6.22.
I don't know if something is wrong with the controller or what?
Those weird characters between lines and then the system hanged with floppy light turned on.

The ST225 is apparently a type 2 drive: https://www.os2museum.com/wp/seagate-st-225-just-wow/

How does the system know you swapped the 5.25" drive for a 3.5"? Did you change a BIOS setting?

I tried several settings for the hard drive, starting from type 1, so I tried type 2 already, I've gone to type 10 and then stopped.
Settings aren't stored because the motherboard has a battery holder but I haven't enough battery to populate it:

Every time the computer is turned off for enough time I have to reconfigure the bios
There is another floppy drive (the black one) but i'm unsure if it is 720k or 1.44mb furthermore the original floppy cable has older connection ports (and a sort of adapter for the black floppy drive), that's why I used a working 3 inch drive that I have around.

A video may be more useful than many words (please notice the sound of the hard drive, I don't know if it's ok or not):
https://youtu.be/kxyCpwG90zc