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Seeking help on reviving an IBM 286 clone

John said:
Your right Terry! It is a 34 pin and it does have a second connection, most likely a 20 pin. I pulled an old seagate HD out of another computer that I had laying around and I'm trying to get it to work. The only problem is I can't remember how (which direction) the cable attached to the HDD board. I guess I have a 50/50 chance on getting it right.
Click to expand...

If the designer had any class at all, the cable will be keyed in some way to prevent mishap. OTOH, if it is not keyed, then look closely at the cable and it's connectors, both on the card and on the drive. The cables should have a red line along one side of them. That will indicate pin #1 on the cable. Now, looking at the controller card and there should be some kind of marking near the connector (usually a 1, next to pin #1). Match up the red stripe to the #1 pin, then do the same at the drive end. If that is not marked, most drives (but not all) have pin #1 farthest away from the power connector.
The best thing to do, with those old drives, is to swap-out the controller board along with the drive, to avoid any formatting problems or incompatability between the drive and controller. (That way, you don't even have to disconnect the cables, so you won't get confused which way they go back on). Good luck, hope this helps...

--T
 
To late, I have already pulled the cables off (hence may dilema). Do you think that the HDD controll board is marked in some to identify the first pin? Keep in mind - the cables are removed from HDD board and hard drive. The one end has a key like you mentioned. I'll have to take a real close look at the board tonight.
 
Be careful. ESDI and MFM share the same cabling, but they are not compatible.
 
mbbrutman said:
Be careful. ESDI and MFM share the same cabling, but they are not compatible.
Click to expand...

OTOH, RLL and MFM drives are sort of compatable. RLL drives can be formatted to MFM, but not the other way round.

BTW, if the board does not have a numeral 1 screened on it, there's still a chance to identify pin #1. Look at the reverse side (solder side) of the board, at the back of the drive header. Most of the time the solder pad for pin #1 is square, while all the other pads are round. (This doesn't always apply, YMMV).

--T
 
mbbrutman said:
Be careful. ESDI and MFM share the same cabling, but they are not compatible.
Click to expand...

But connectong an ESDI drive to an MFM controller won't be fatal.

I once sold a 286 with an ESDI drive to a semi-knowledgable friend. I wasn't around when he wanted to upgrade so he took it to a local shop. They tried all sorts of combinations to put two drives in the same box. The moron in the shop insisted that the ESDI drive was dead, although he didn't know it was ESDI.

When I returned I was quickly able to transfer his software to the new drive using a null-modem cable between two computers.
 
Terry Yager said:
OTOH, RLL and MFM drives are sort of compatable. RLL drives can be formatted to MFM, but not the other way round.
Click to expand...

I've been able to convert an RLL drive back to MFM. It took several low-level formats but it worked.

Is my memory correct that there were different RLL formats? Aren't there 25 and 26 SPT formats?
 
barryp said:
Terry Yager said:
OTOH, RLL and MFM drives are sort of compatable. RLL drives can be formatted to MFM, but not the other way round.
Click to expand...

I've been able to convert an RLL drive back to MFM. It took several low-level formats but it worked.
Click to expand...
Oh, that's easy... The hard thing to do is go back to RLL after using the drive as MFM.
Is my memory correct that there were different RLL formats? Aren't there 25 and 26 SPT formats?
Click to expand...

Well, yes...and no. MFM (modified frequency modulation) and RLL (run length limited) are both methods of encoding data for storage on some medium, usually a magnetic disk. They have nothing to do with the actual formatting of the medium, even tho we commonly speak of "MFM format", etc. (IBM format 5.25" floppy disks use MFM encoding, but are only 8 or 9 sectors:track). The yes portion of my response has to do with whether or not you are speaking of strictly MSDOS-type computers. In the world of MSDOS, RLL drives are usually (always?) formatted with 26 S:T, and MFM drives are 17 S:T. However, different OSs may format either kind of disk any way they want to (within the phisical limitations of the hardware). So yes, RLL (& MFM) can be other than 26 sectors, but not usually under DOS.

ESDI, OTOH (even tho you didn't ask), is neither a formatting standard or an encoding method. ESDI (enhanced small device interface) refers to the electrical interface (hardware) that controls the device (via software). Other interfaces include the ST506 interface that MFM and RLL drives usually attach to, as well as others (SCSI f'rinstance).

--T
 
Hmm.. I have a vague memory of once managing to kill a hard drive in college where we had a few 286 systems with different interfaces. Back then, none of us had the knowledge what is what, and it ended up in bad smell and maybe even a puff of smoke. I can't remember if it was due to connecting the wrong type of drive to the wrong interface or because the BIOS was set with wrong parameters. :oops:

Oh well, that is more than ten years ago, and those machines most probably have been "recycled twice" since then.
 
carlsson said:
Hmm.. I have a vague memory of once managing to kill a hard drive in college where we had a few 286 systems with different interfaces. Back then, none of us had the knowledge what is what, and it ended up in bad smell and maybe even a puff of smoke. I can't remember if it was due to connecting the wrong type of drive to the wrong interface or because the BIOS was set with wrong parameters. :oops:

Oh well, that is more than ten years ago, and those machines most probably have been "recycled twice" since then.
Click to expand...

More likely, the drive was plugged in backwards. (My memories of such incidents are anything but vague). Once, I killed the 10Mb (MFM) drive & the controller in my Tandy 1000HD by connecting the data and/or control cable backwards. Another time, I did in a 2Gb (full-height) SCSI drive by plugging the SCSI cable in backwards (that one went out with a bad smell, a puff of smoke, a loud noise and flash of light). I killed a Celeron 333 mobo once by plugging the power cable to the CD in up-side-down (I was working "blind", by feel). The plug went in easily, so I figgered it was ok, till I turned on the machine. Another mishap was when I plugged in the power connector to a 3.5" floppy drive up-side-down. That one only took out the floppy controller, which was built in to the mobo. That computer is still on the job today, minus any floppy (I gave it to my nephew).

Connecting the drive to the wrong kind of interface (with similar cableing) is not likely to do it any harm, it just won't work. Neither should setting the wrong parameters in the bios setup.

--T
 
Terry Yager said:
I killed a Celeron 333 mobo once by plugging the power cable to the CD in up-side-down
Click to expand...
Normally these cables only fits one way, at least on European systems, or the connector was very worn. I once killed a motherboard by assuming the fan power connector was a jumper block and short circuited some 12V upon booting.

I believe that we (or I rather) actually by accident or curiosity changed the BIOS settings from user defined disk to one of the fixed ones, and the drive really didn't like to be accessed with the wrong assumptions about heads, cylinders etc. Or maybe the user defined settings were lost and it could be read off the disk label.
 
Problems with hard drive

Problems with hard drive

Ok I have the hard drive connected to the controller card in the proper order (pin one to pin one...). CMOS will allow me to run diagnostics on the dive which seam to be telling that every sector on the disk is bad. When I got this HD I was asured that it was working. Would anyone be willing to list out - step by step - the procedure for getting a drive up and running on a 286 machine. Please.
PS .. I have tried DEBUG, FDISK, and FORMAT ... The guy I got the drive from said I sould try a low level format?? I haven't been able to find out much about how I would do that, although at www.computerhope.com they did mention the word but not much more.
I used DEBUG to erase all disk partitons.... Seemed to work as expected.
FDISK because the DOS manual said that you had to... Just get errors.
And FORMAT c:/s because thats what I thought you should do.... Invalid drive error.
The HD is a Seagate ST251 if it maters and I selected drive type #40 in CMOS setup for it.
 
Usually, when you get errors on every sector it's because the drive geometry is set wrong in the CMOS. For an ST-251, the geometry should be (IIRC) 6 heads, 820 cylinders, 17 spt for a total of 42Mb (look it up at Seagate's website, just to be sure). To low-level format it there are two different (common) ways, depending on your machine's BIOS. Either there will be a formatting program in your machine's CMOS setup, or you'll have to find a LL format program that runs from disk. (A web search should turn up a few). After the LL format, then you'll have to run FDISK to partition the drive. Depending on which version of DOS, you may not be able to use the whole drive as a single partition. (Versions before 3.31 were limited to 32Mb for a partition's maximum size). After setting up the partition(s) with FDISK, then rebooting the machine, then you run DOS's FORMAT to high-level format the drive, then install the OS and you're there.

--T
 
Ok, I down loaded a LLF program from a site. When I ran the program it had an error on every track. It (the program) had a write/verify option which I chose. This is what generated the error message - VERIFY ERROR ID - or something like that, however the format option seamed to work fine. I believe that I have the drive connected correctly. The drive is connected to J2 (34 pin) and J3 (20 pin?) on the controller card. I don't know what else there could be with the execption that the drive is trashed. Any have any good suggestions on how to resolve this problem?
 
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