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Amstrad PCW 8256

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ngtwolf

Veteran Member
Joined
Apr 6, 2018
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991
Location
Los Angeles, CA
Hi All,

I was given an Amstrad PCW 8256 the other day as not working, so I finally took a quick look at it yesterday. When it turns on, the disk drive spins and the light comes on, then the screen comes on and is completely green. I don't have any disks but I'm curious if this is normal before booting or if it should be displaying something. I assume i'll have to do some kind of Gotek solution or find some 3" disks to actually use it, but I'm just trying to figure out if this is a repair project or expected behavior so I can figure out the next steps.

Thanks!
 
Sounds about right--the screen is graphics only and so needs to load the OS before you really see any text.

The system does look for a READY/ signal from the boot drive.
 
It's the drive belt that needs replacing.

Open it up and you'll find the drive belt has melted into a sticky black goo - clean it all up and replace the belts and the machine will boot from disk and clear that bright green screen.
 
He doesn't have any CF 3" disks--and they're pretty hard to come by in the US.

However, with some care (particularly with the power connector), a 3.5" 720K drive works just fine (you will need that READY/ signal, so a 1.44M drive like an SFD-321B jumpered correctly will also work).
 
Chuck(G) said:
He doesn't have any CF 3" disks--and they're pretty hard to come by in the US.

However, with some care (particularly with the power connector), a 3.5" 720K drive works just fine (you will need that READY/ signal, so a 1.44M drive like an SFD-321B jumpered correctly will also work).
Click to expand...

Okay, great, I'll give that a try. I'm assuming there are disks on the net I can just IMD with a PC onto a 720k disk? (meaning not some crazy format like the Mac's that won't image on a PC?).
 
The format is pretty tame with no surprises. But watch out for that power connector! It may look the same as a standard 3.5" power connector (4 pin), but the +12 and +5 lines are swapped. Unless you correct that, you'll let the magic smoke out of any 3.5" drive.

I'm pretty certain the mod is covered somewhere on the web.
 
ngtwolf said:
Okay, great, I'll give that a try. I'm assuming there are disks on the net I can just IMD with a PC onto a 720k disk? (meaning not some crazy format like the Mac's that won't image on a PC?).
Click to expand...

I'd avoid even trying to use a regular 3.5" drive and just go right to Gotek... Although I suppose if you can put in a Gotek you can also put in a 3.5 black drive. Now, can are there disk images to use with the machine via a Gotek or 3.5" drive? Hmmm.
 
Chuck(G) said:
I can probably create a few 3.5" IMD images if there are none from our UK friends available.
Click to expand...

Let me check around and if I run into problems I'll likely take you up on that. And thanks for the warning about the power connector, I might not have caught that. :)
 
misterblack said:
I'd avoid even trying to use a regular 3.5" drive and just go right to Gotek... Although I suppose if you can put in a Gotek you can also put in a 3.5 black drive. Now, can are there disk images to use with the machine via a Gotek or 3.5" drive? Hmmm.
Click to expand...

Yeah, as you saw yesterday :) , it doesn't look like either would fit as is, so I'll probably have to do the gotek with a replacement 3d printed mount. For now though I just want to confirm it's working before I proceed on about permanent solutions. It's also possible I don't care that much about actually using it (considering that kaypro, Osborne and even the trs-80 can do CP/M) and might just leave it stock. It's a nice looking system, as is.
 
They're nice little CP/M 3 (or CP/M Plus, if you prefer that naming convention) systems. Good screen, decent keyboard. Coming up to a solid green screen with the occasional flashing is normal behavior if you don't have a boot disk.

The second drive bay should take a full-height 720K floppy. As Chuck said, fix the power cable or you'll blow up whatever you plug in there. If you do find some CF2 disks, you can plug the CF2 drive into a PC (again, correcting for the difference in power connector) and write them out with ImageDisk.
 
The only problem with the 8256 is that unless you have an expansion adapter, there's not much that you can do with it. The printer was a gutless proprietary interface (the same gate array chip that provides the printer interface also provides the basic bootstrap code).
 
I suppose that might work--but I was thinking of a way to get a serial port onto the thing. 720K floppies don't bother me much--it's still more than the old single-density single-sided 8" systems had. After all, how much software are you going to put on this thing--more than a couple of megabytes? Before I gave one of these away, it was populated with 512K of DRAM and the combination of the 720K drive and the RAMdisk was more than I needed for most things.
 
Huh, neat! I didn't know anyone had already reproduced the expansion device with the serial port. It is indeed supported by Kermit.

I'll probably do a PCW -> Glitchbus bridge board at some point. The expansion connector is basically the Z80 lines.
 
I've just been through this pain with a PCW9512. The other main thing to remember is the 3" drives in an 8256 are different, assuming it has two. Top is a single sided 360K and the bottom is double sided 720K. Also the interface is 26 pin, not 34. Amstrad managed this by removing the 'unnecessary' signal lines. It's not possible to directly connect one to the other.
On sellmyretro there is a bloke called Zaxon (Piotr Bugaj) who has produced a micro gotek that has both 26 and 34 pin connectors and has the added bonus that you can replace the 34 pin header with a plug and connect it directly to an Amiga 600/1200. A bargain at around £30.

You also need a boot disk for the PCW8256 because the boot firmware is on the disk. CP/M disks for other Amstrads won't work.

(I can't link to much from here because I'm at work and net nanny says no)
 
The standard 8256 had one 360K CF2 drive. I replaced mine with a 720K Teac FD235F, which has the "ready" line.

You can make a slight (i.e. 1-byte change) to the boot floppy and the thing will recognize the 3.5" drive as a regular 720K unit. I've posted on this here years ago.

I got rid of my fully-populated (512K) 8256 because it sat unused for several years. I'm more of a utilitarian person than a collector. I think an AT&T PC 6300 went with it--again, no use for it.

The sad fact is that the MCU used in a vaping pen today is probably more powerful than the Z80 in an 8256. Moore's law marches on...
 
If the disk drive is spinning, then it might work. Your description sounds just like my PCW here, which is working fine (original drive repaired, add-on 5.25 and 3.5" drives (alternative B:) and JonB's uIDE virtual HDs (13 @ 8Mb drives on a 128Mb DOM) connected to the expansion slot). However, the drive MGHT be spinning, but if the rubber band is degraded at all then it might not be running at the right speed, and might not read a disk.

There are disks to be had via the web, you need to see if you can find the 2 disk (4 separate sides) standard system disks, although at a pinch you just need the CP/M boot disk to confirm operation. You might not need the Locoscript side (which is a separate boot), and the remaining 2 sides are mainly standard CP/M utilities.

Even if you have a working drive, you still have the problem of getting software onto the machine, and verious options have been suggested. Adding a 3.5" drive as B: would keep the machine closer to it's original state, which may be what you are most interested in? The Gotek option has some complications, as the disk formats (and thereby the image formats) are different for the A: and B: drives, and the A: drive (used for booting) may not cope with the usual B: format).

Lots of .DSK images can be found thru the web, everything from system disks to games. Easy to use with the Gotek, more of a problem if you want to get them onto a 3" disk"

Geoff
 
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