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Olivetti M24 - No POST

You don't have 2 floppies? Oh, okay. I use a hardhard, so I assumed that everyone was using that.

Sw 1 - on (48 TPI)
Sw 2 - off (fast start up for floppy)
Sw 3 - off (no HD or one with its own BIOS)
Sw 4 - on (reserved)
Sw 5,6 - off, off (80x25 monochrome display)
Sw 7,8 - on,on (1 floppy drive)

The gist of this is that the BIOS won't look for a hard drive, unless it has its own BIOS. So if you're getting a hard disk error, it's coming from the HD controller BIOS. If yo boot from floppy (I assume that you can), you should be able to see the BIOS as absolute address C8000.
 
With it set for one floppy, the message "Primary boot strap: DISK READ ERROR" still appears when the drive and controller are completely removed from the machine, so it cannot be a message from the controller.

Looking at the controller I noticed that two of the chips which I have ringed in red on the photo below are the opposite way round to all the other chips on the controller card. Both are socketed. Is this a bit odd?

IMG_20120806_113756.jpg
 
Yes, it's odd--and lousy engineering practice if it's what was intended.

Let's check the big chip the HDC9226. I've got the datasheet here in front of me and it says that +5 should be on pin 24 and ground should be pin 12. If the chip really is reversed, it's likely toast.
 
Won't be able to test it electrically for an hour or so. Looking at the printing on the circuit board itself those two chips do have the little knocth marked at the other end from all the other chips though, so it does look like the orientation of them is as designed.
 
I have a disk that it boots off, but its origin is unknown. My tweening machine should be up and running properly tomorrow. I've seen it boot through to time/date prompts though.

What do yo have in mind?

The disk images I have came are .img files. What is the best utility to write them with?
 
With your hard disk card inserted and DOS booted, do the following and tell me what you see (your keyboard input is in boldface):
Code: 
A>[b]DEBUG[/b]
-[b]DC800:0[/b]
[i]...some output...[/i]
-[b]Q[/b]
A>

This will tell us if your HD BIOS is even present in memory.
 
Sorry Chuck, bit of a delay. I wrote a 5.25" DSDD floppy disk with a disk image of AT&T DOS 3.3 using a modern PC with a 1.2Mb 5.25" FDD in it.

To start with it was booting in the Olivetti. Now it won't boot in the Olivetti but will in the modern PC.

I had a bit of a struggle finding a program that would write img files to the 5.25" FDD in Windows. Win32image and Winimage both refused to do so, so I ended up using rawdisk.

I'm trying to find a geniune copy of DOS amongst all my stuff instead but not luck atm.

Its a bit annoying. My machines are either too old to be a good tweener or too new. I have nothing in the 386 - Pentium 3 range now :(

Im beginning to wonder if DSDD disks are only reliable if written in a DSDD drive.
 
Not as far as I know. The M24/6300 supported 96 tpi drives right from the get-go. A 96tpi 5¾" drive in DD mode is virtually indistinguishable from a 3½" 720K drive.
 
I finally got my tweener machine together. I fitted the FDD from the M24 into it just long enough to write some system disks. The media I have is DS-DD, and the drive is a Fuji 5451A02.

I boot the tweener from its HDD which is running DOS 6.22, and at the command prompt I tell it to format the 5.25" floppy drive. It says "Formatting 360k" but when it completes the format it says its only done it as a 180k and accordingly I struggle to write 360k disk images to it!

Any idea why this should be? Defective floppy? Or defective head on the drive perhaps?
 
It happens that if an error is detected on side 1, cylinder 0, that DOS will, instead of discarding the floppy entirely, attempt to use it as a 180K floppy. No, you don't get any notice that this is happening. Try some other media, and format it explicity under 6.22:

FORMAT A: /F:360 /U

And see what happens.
 
IIRC, whenever I made a floppy from an image I didn't format the disk first as the image restore program did that as part of it's included process.
 
Something is definitely odd about this Fuji drive.

I've tried several floppies from this batch, and it formats them as 180k disks.

They are definitely double sided, and contain data and programs before I reformat them.

It will NOT run the programs on the disks, yet if I put them in the 1.2Mb drive, it sees them as 360k disks, and can run the programs on them.
 
There is no information available on that Fuji drive.

I think you should use another 360k drive before you waste any more time.
 
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