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Old harddrive (Miniscribe 8450 XT) not working from HeadStart Explorer XT PC

G

gurby

Member
Joined
Jul 15, 2010
Messages
30
Hello,

I have 2 old HeadStart Explorer XT PC's.
Got them because it was my (read: my parents') first computer 20 years ago on which I learned the basic's of DOS, (gw-)Basic, etc. Got them both for free and in both PC's the harddrive is not working anymore.

I hear it spin-up, I see 1 primary partition in FDISK and I can remove it but when I try to create a new partition it is looping. Booting from exisiting partition, format.com, it doesn't work at all.

Will a low level format work? I've tried already with the DOS 3.31 debug.com but on all commands I tried I got a divide by 0 error message. Are there good (rll) disk repair and format tools which can be run from a 720k dd floppy?

If you can give me some hints on how to proceed getting this working.. would be great!
And if the drives would be really dead, can I get a good one (of alternative) somewhere for reasonable prices?
 
To do a proper low level format, you will need to open up the machine, and determine what kind of controller is connected to the HD. Once you know that info, you can look up the address of the low level format program.

For example:

Western Digital
G=C800:5 -or- G=C800:800

for Adaptec
G=C800:CCC

for DTC (Data Technonolgy)
G=C800:5

for OMTI
G=C800:6
 
Hello,
Thanks for your reply.
The mainboard in the computer itself doesn't seem to have a harddisk controller onboard, is that possible? One cable which has approx. 50 pins goes to the harddrive with a printboard attached. The main chips on this board are the AIC-010FL Adaptec, Inc. Programmable Storage Controller and a MINISCRIBE 01100003 and a OG1 HD63B03R1CP

During the machine's boot process I only see a headstart explorer logo in the screen, not any POST information at all. Will there be a way to enter something of a BIOS?

THanks in advance!


Regards Gerben
 
I don't think you can low-level format these IDE drives (yes, IDE, not MFM). You could try something like SpeedStor, but unless the function is supported by the drive itself, LL format is a nonstarter.
 
An IDE drive?
Where do you base that upon?

Do you think I can easily change the drive for another (IDE) drive, not especially the same model?
 
Well, first of all, you have a single signal cable, not two (MFM and RLL drives use two--a 34 position and a 20 position cable--there are exceptions, but they're generally limited to laptop drives and hardcards).

Secondly, my CSC "Hard Drive Bible, VIII Edition", says the following about the 8450XT:

42MB formatted capacity
4 Heads
805 Cylinders
26 Sectors/Track
45 msec. Average access time
XT-IDE interface
3.5"x1" physical form factor

An XT-IDE interface is the very old 8-bit IDE interface and is generally not compatible with PATA IDE drives. If your drive is really toast, you might be able to replace it with a low capacity (128MB) CF card or Microdrive and a CF-to-IDE adapter.
 
Please find these pictures to give some more information:


The mainboard:
Foto-3KNPVL3B-D.jpg


The pins connector on the main board for the harddisk connection:
Foto-MASNRNGP-D.jpg


The cable to connect to harddisk:
Foto-XH7IAUHJ-D.jpg


This connector goes on the mainboard:
Foto-ANPG3OWY-D.jpg


This connector goes on the diskdrive:
Foto-OMQSPRZS-D.jpg


Finally, the drive itself (top) :p:
Foto-DF8UX6YN-D.jpg


drive underside:
Foto-ZKROGPFZ-D.jpg


Drive underside (2):
Foto-GYS4WBHZ-D.jpg


Drive 3:
Foto-REF3FJXT-D.jpg


Drive 4:
Foto-4FYZ4VBS-D.jpg


Drive 5:
Foto-7XDKGI3W-D.jpg



I am very interested in tooling to try if I can rapair and re-use the harddrive. Only the sound of this drive is authentic :p
Also the alternative (CF-card and CF-to-IDE) sounds very interesting.

After seeing these pictures, you still think this is possible? COuld you please more specifiy your tips? Thanks in advantage!
 
Chuck(G) said:
An XT-IDE interface is the very old 8-bit IDE interface and is generally not compatible with PATA IDE drives. If your drive is really toast, you might be able to replace it with a low capacity (128MB) CF card or Microdrive and a CF-to-IDE adapter.
Click to expand...
You mean there are CF-to-XTA adapters? Where?
 
If you're wondering about the drive and interface, check in with the Tandy folks. I believe the Tandy 1000TL used the same XT-IDE drive setup.

I think your best bet would be to install one of the 8-bit controllers offered by Hargle on this forum and use a conventional IDE drive.
 
The Miniscribe XT series hard drives are early, proprietary "IDE-XT" drives. They are not compatible with standard IDE-AT or ATA, including the so-called homebrew "IDE-XT" controller much talked about on this forum (which is more correctly called an ATA controller adapted to the 8-bit XT bus, not an actual "IDE-XT" controller!).

In fact, Seagate, Western Digital, and Miniscribe all had their own versions of "IDE-XT", and all three were not compatible with each other. Or, at least I had no success in getting a Miniscribe drive to work with a Seagate controller, or a Seagate drive to work with a Western Digital controller.

As far as I know, the only IDE-XT hard drive which had any kind of cross-compatibility with the standard IDE-AT / ATA interface was the Seagate ST-351A/X, with the "A/X" indicating that it was compatible with both AT and XT controllers. This drive, along with the XT-only Seagate ST-325X, was used by Radio Shack in their later Tandy 1000 series machines with the built-in "SmartDrive" IDE-XT controller.
 
Anyway, due to the scarcity of these Miniscribe IDE-XT drives, and the totally non-compatible nature of its controller, the best solution would be to find a working Miniscribe 8450 drive (just the plain 8450, not the 8450XT), which is a relatively standard ST506 RLL drive -- and then swap its circuit board with the one taken from the dead 8450XT. The mechanics of the drive should be identical between the two; only the circuit board is different. And if I remember correctly, the Miniscribe IDE-XT controller does provide some kind of low-level format routine if you enter g=c800:5 in DEBUG -- that's assuming the onboard controller on this Headstart PC uses the Miniscribe ROM, though.
 
vwestlife said:
Anyway, due to the scarcity of these Miniscribe IDE-XT drives, and the totally non-compatible nature of its controller, the best solution would be to find a working Miniscribe 8450 drive (just the plain 8450, not the 8450XT), which is a relatively standard ST506 RLL drive -- and then swap its circuit board with the one taken from the dead 8450XT. .
Click to expand...

Doesn't that assume that the HDA is bad, and not the PCB? In any case, it still might be better to use Hargle's XTIDE controller and a standard IDE drive. ISTR that attempting a LL format on these old XT-IDE drives was a sure way to brick them.
 
I already tried DEBUG g=c800:5 but this didn't work, I got an divide by zero message and that's it. I tried a whole bunch of possible commands for all controller type but all without any luck..

The IDE-XT controller... this should work on all XT pc's with 8bit ISA slot?
I've contacted Hargle to see if I can get any
 
By the way, the 8450XT drive shown in the pictures is even stranger than I first thought. It uses a 50-pin connector, just like SCSI, but it's not -- it uses the extra pins to carry the power lines through the same ribbon cable as the data lines! This may have been a special HeadStart OEM specification drive, because the Miniscribe 8225XT drive I remember used a regular 40-pin cable and separate 4-pin Molex power plug.
 
Before we get too deeply into the hardware and replacing stuff, maybe we should double-check the basics; after all, it did originally spin up and read OK and we're not getting specific hardware errors but divide by zero...

Forget about the low-level format for now; exactly what are you doing with FDISK and FORMAT, and in what sequence? And do you have any other bootable DOS disks, preferably a different version?

Can we assume that no cables have been disturbed or that at least they're definitely back the way they were, and that no jumpers or switches have been changed?

Do you have a way to get diagnostic software from the Internet to the system in question?

And where are you?
 
I'm in Holland, Utrecht region.
With FORMAT I can't do anything at all because C is unaccessible. With FDISK I see one primary DOS partition, can remove it but cannot create a new one. I hear the harddrive 'looping' and no response at all at that point. I did not try yet to see at a 2nd attempt if the previously-removed primary partition is still there or removed indeed..

Only have DOS 3.31 original disks. Also have DOS 6.22 but these are high density disks while the headstart only reads double density (720K).
Cables are fine, nothing changed (by the way, I have 2 HeadStart explorers standing here both with exactly the same issue).

If one of you can provide me with diagnostic software that would be really great.
Yes I can get them on the machine, as long as they are not bigger than 720K....
 
Well, if you can copy diagnostic software then you should also be able to create a DOS 6.22 boot disk with the standard tools from the 'net, no?.
I only ask because the DOS disk is the only thing that's common to both systems and they both have the same symptoms, and there were certainly issues with some versions of DOS 3.x and hard disks >32MB

Are these the original disks specifically for these machines? I wonder if possibly this version of DOS needed a special driver or overlay to access HDs >32MB.

As to good diagnostic software I'll defer to the other experts here; spinrite is the usual recommendation but I'm sure you'll get several good suggestions.

If you're lucky then it's just some software snag or incompatibility; at least the disk is spinning, you're not hearing nasty noises, and no actual hardware errors are being reported.

For that matter, I wonder if there could be a memory problem that's causing the DOS tools to crash.. unlikely they'd both have the same problem though. How much memory do they have?

Good luck!
 
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