🚀 go-pugleaf

In article: <818357800snz@stuarts.demon.co.uk>  Tony Baker <Tony@stuarts.demon.co.uk> writes:
> Calling any old-IBM-PC experts!
> 
> Got this problem with an old IBM 5170 PC (vintage 1985-ish) that my local
> church has asked me to try to fix - they were given it for free, so it might
> not be worth doing much with. It has a 3.5" floppy as A drive, a 5.25" as 
> B drive, and a 20 meg hard drive (at least there is a big 20 on the label 
> (the disc surface defects label?) stuck on the front of the HD case, I saw 
> when I opened the PC case up.
> 
> Basically, it seems that the only problem is that the C drive has failed. 
> When you switch on you get the usual RAM self-check, ending with the messages: 
> 
>         02688 KB OK 
>          162 - System Options Not Set - (run SETUP)
> 
>          (RESUME = "F1" KEY)
> 
> and two loud beeps from the speaker. During the time the system is testing
> itself, you get various clinking noises from the HD, as if the heads were
> bouncing off the surface of the disc, or somesuch.
> 
> If you then press F1, the system beeps again, and loads 'IBM Personal Basic,
> version C1.10 Copyright 1981', which seems to work ok as Basics go. Dunno 
> where the code for the basic is stored, seems too much to be in NVRAM, but 
> dunno where else it migt be; you IBM gurus will know. The only phunnie is 
> that the command "System" doesn't exit you from Basic, which it does do on 
> a modern PC - although that might be because there is nothing to exit to 
> I suppose!
> 
> I then copied COMMAND.COM from MS-DOS 6.2 onto a 3.5" disc, then into 
> the A drive, then CTRL-ALT-DELd the system, which gave the same message as 
> above, without the memory check message of course. If you now press the F1 
> key, after the system bleep on pressing F1, after a few seconds MS-DOS 6.2
> loads itself, and you get the A:\> prompt.
> 
> So far so good. Things like dir, del, type and B: then work as expected, 
> but when I tried C: I got the message 'Invalid drive spceification' - 
> which is why I thought the C drive was duff. For the record, it's an 
> IBM HD, type 0665. Big brute of a thing!
> 
> That's as far as I've got. Any help anyone can give me to get the thing 
> as up and running as an 80's PC can be got would be gratefully received.
> Can I just buy any HD and fit that? And what do I do then? What do I need
> in the way of software? I've not got any full version of MS-DOS, just 
> upgrades - to v5 on 5.25", and to v6 and v6.2 on 3.5". The only other 
> thing I've noticed so far is that when you do a B: (to the 5.25" floppy 
> drive, the fan on the power supply slows down for a few seconds, 
> presumably because the extra load from the 5.25's motor loads the supply
> rather more than the 3.5"'s does. The 3.5" must have been added in the
> last few years, as there were no 3.5" discs in the mid 80's were there? 
> I suppose the assignment of the 3.5" FD to drive A and the 5.25" to B 
> is held in NVRAM. Is that right?
> 
> If anyone out there can help I'd be very grateful. If you do feel you can 
> help and you need to talk for a while, if you'd email me your phone 
> number, I could ring and have as long a chat as it takes.
> 
> Thanks for any help anyone can give me.
> 
> I'm not sure if this posting should be in demon.tech.pc or ~support.pc, so I
> am going to post it to both - if I can work out how to do that! (Newbies
> strike again!). Don't flame me PLEEEEEEASE.
> 
You need a new battery for the CMOS ram, and a copy of the 'SETUP' disk.
The IBM, stores the BASIC, in part of the ROM, just below the BIOS.
Basically few machines have NVRAM, some modern boards use 'flash' memory
for the BIOS, but most use an EPROM for the BIOS, and a small amount of
CMOS memory, built into the same chip that provides the clock, to hold
their configuration information. The battery powering this, is either a
rechargeable, or a primary cell. The IBM (I think) used a primary cell
type, and this has a life of several years. Now it has run down, the
machine doesn't know what shape/size of disk it has attached, hence your
problem. The code to write this information to the CMOS memory, on modern
machines is held in the BIOS ROM, in the location where the IBM stores
it's BASIC. So you have to replace the battery, get a copy of the disk,
(which will probably be on 5.25"), swap the drive cables over, so that
the machine boots off the 5.25" drive, and then set the options back up!
You will have to get the type of the hard drive, since you will need to
know a 'TYPE number' for this, that can be worked out if you post the
tracks/heads etc.
At this point various screams are heard as you beat your head against a
convenient wall!
You don't post where you are. The easiest solution, is to remove the
motherboard, and replace it with a slightly smarter '286 board, that has
the standard BIOS utils available. With any luck, you will have CASE, PSU,
DRIVES, VID CARD, MONITOR etc., in fact everything to make a machine.
If you are near ESSEX, I can probably find you an old board of this type
working.
Your HD, may well be working, but machines pre, the early 90's, can have
trouble with modern IDE drives, so buying a new drive, might well not be
a solution.
If you've not completely given up, post a note back, and we can talk more.

Best Wishes
 
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| EMail roger@ttelmah.demon.co.uk                                 |
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