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Olivetti M24 - No POST

You should really use a cleaning diskette, especially in stubborn cases like this, although even that may not suffice. I still think you need to use another drive altogether.
 
Stone said:
You should really use a cleaning diskette, especially in stubborn cases like this, although even that may not suffice. I still think you need to use another drive altogether.
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I've bid on an IBM half height 360K FDD on Ebay which ends in a couple of hours. Failing that I could borrow one from my 5155 or try a full height unit from a 5160, but in both cases they'd be from machines I haven't looked at yet.
 
This is only for a test. You do not need to install it (permanently).

You have a 5160 you haven't looked at yet? Now's a good time! :)
 
MikeS said:
Yes; a lot of HD drives have jumpers that accomplish the same thing.

But of course you will then have a 720K (80 track, 96TPI) drive; I suspect that's not what you're looking for.
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I haven't tried it, but the M24 does have a switch for 720K drives. Exactly what happens when it's thrown, I have no idea. However, what's certain is that you won't be able to create disks readable by your 5150.

A Teac FD55B* (*meaning options for latch placement, etc.) is a very good drive to use in your M24. I've also used Toshiba and Matsushita drives with good results in the 6300.

On the other hand, if you don't have a stock 360K floppies with data on them, you might consider just sticking a 1.44M drive into the M24 and deal with 720K DSDD floppies.
 
Right I finally have working 5.25" 360K floppy drive in the machine (thanks Malc), and IBM-DOS 3.3 (thanks again Malc), which I have backed up etc etc.

So I can boot to DOS and run DEBUG.

What is the first test you need me to do Chuck?
 
Ok!

IMG_20120901_233606.jpg

If I press D and Enter a few more times I start to see:

IMG_20120901_233632.jpg

I've tried g=C800:5, g=C800:0, g=e800:5, and g=e800:0 and all just respond with the cursor moving down to the next line, and the machine locking up.
 
You don't want to use the g= command unless you know what's at the place you're going to. G= tells the CPU to jump to that location. If there's garbage there, well, you know what happens.

D is the dump command. What looks very odd to me is that contents on the second display appear to duplicate every 16 bytes. That says that there's a disconnect between bit 4 of your controller BIOS PROM and the bus.

If the EPROM on the controller board is socketed, examine it carefully--make sure that no pins are bent or missing.
 
Examined the BIOS chip carefully. No sign of any problems. Removed it. Cleaned pins carefully and reinserted it. Still looks the same in debug.

Got another Western Digital MFM controller. Tested post with no drives connected.

New line during POST: "Adapter ROM at C800:0000" and after a few seconds it adds " 1701" to the line so that is much more promising.

I guess now its time to try it with one of the drives.
 
Connected ST225.

Booted from floppy. Machine can't see C:. Tried Fdisk but it reports no fixed disks present.

Into Debug.exe. Ran G=C800:5 and did low level format of drive.

Fdisk now works. Formatted drive. 20Mb with no errors.

Reformatted with system tracks. (forgot about sys but it's been a long time).

Machine now boots from HDD no problems.

Made a DOS directory and set about copying the contents of both disks into it.

"Parity error on Systemboard". + lots of screen garbage.

Never rains....lol

Ideas please?
 
I have the disk image. My only working 360k FDD is in the M24 atm, so I'll have to swap it back to write the image.

Will report back as soon as I have had a chance to do this.

Thanks again for everyones input.
 
Ive been running the memory test within "customer.exe" today. Ran it half a dozen times and had no sign of the memory error.

I'm off to Scotland for a week now so it will have to wait until I get back.

Thinking about it, when I was getting the parity error the machine was hooked up only a few feet from a dish washer that was running at the time. I presume the dishwasher is unlikely to have caused any electronic interference?
 
Well, if they're sharing the same circuit, it's entirely possible. Dishwashers exhibit nasty surges in power consumption. Even if they're not sharing the same circuit, but if the wiring is close enough, surge currents can inductively couple to another line. I know there in the UK that you often use "ring mains"; in the USA, we're more of a star topology--i.e. branch circuits extend from a single distribution panel with low current (typically 15-20 amp at 120VAC) circuit breakers. In my house, the dishwasher has its own circuit, but that's probably not true in the vast majority of older homes.
 
More mundane, but does the dishwasher vibrate a lot, mechanically speaking ? Maybe it's mechanical vibration affecting an intermittent on the M24.
patscc
 
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