Floppy problem on 80286 machine

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Floppy problem on 80286 machine

Postby Columbo on Sun Feb 23, 2014 4:44 am

I recently acquired an 80286 computer running DOS 6.2 from a Seagate ST-225 hard drive. It has 2 floppy drives, one 5.25" and the other is a 3.5". I was hoping to run Clipper 5.0, one of my old DOS programs (a dBase dialect), on this machine but I am having problems with the floppy drives. At first I was getting an FDD controller error but I installed another FDD controller and the error ceased. The problem now is that neither floppy drive can read or write a disk. I am more interested in getting the 5.25" working because my Clipper program is on 5.25" floppies.

Here is what is happening and what I have done so far:

If I do a "dir a:" command, the light on the floppy lights up, the drive spins and then I get a "General Failure reading drive a:". This happens with both drives.

If I do a "Format a:" command, the light on the floppy lights up, and the drive spins. It says "Checking disk format", then it says "Formatting 1.2M" and then after a couple of seconds it says "Invalid media or Track 0 bad - disk unusable".

I have gone into the CMOS and made sure that Drive A is set to 5.25" and 1.2M and that the other floppy is set to 3.5" at 1.44M. I also tried changing the settings to 5.25" and 360K and that the other floppy is set to 3.5" at 720K but I still get the same errors. I tried using Double-sided Double Density disks and also tried using Single-sided Double-Density disks but still get the same error. I also tried hooking up a new 5.25" floppy drive and a new 3.5" floppy drive as well and again I get the same error. I'm not sure what to try next and I can't install my Clipper program onto the hard drive if I can't get the floppy to work.

As is usually the case with these old computers, the battery on the motherboard was dead and it would not keep the Date and Time format so I bought a battery from Mouser Electronics and soldered it onto the motherboard. It works fine now but of course, this would not have anything to do with the floppies.

Anyone have any suggestions that I could try to get these floppies going?

Thanks
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Re: Floppy problem on 80286 machine

Postby Gibsaw on Sun Feb 23, 2014 12:27 pm

Ah, General Failure... who are you and why are you reading my drive?!

Ok... let's check a few of the basics first... I take it you've cleaned the drive heads?

Reading what you've written, I'm not 100% certain whether you mean you've tried DSDD and SSDD as well as DSHD. (You will need DSHD for 1.2M)

It's harder to troubleshoot if we don't know whether this is a 360k or a 1.2M. Can you identify the drive's manufacturer and model?

Assuming the drive to be a 1.2M and set up as such, then if you wish to use DSDD, then you'll need to specify /f:360 (EDIT: I'm referring to format) so that it doesn't attempt a 1.2M.
Last edited by Gibsaw on Sun Feb 23, 2014 2:13 pm, edited 1 time in total.
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Re: Floppy problem on 80286 machine

Postby RonTurner on Sun Feb 23, 2014 1:23 pm

Columbo wrote:my Clipper program is on 5.25" floppies.


If the disks have an extra re-enforcing ring in middle then try 360K (Double Density)

On very rare occasions DD disks can have no re-enforcing ring, but this is extremely rare.


Clean the disk drive R/W head with I.P.A. you can get this from your chemist for around $6

Don't try and cut corners and do it on the cheap with meths.

Use cotton wool buds, remember karate kid "wipe on, wipe off", ie wipe on IPA with one end, dry the R/W head
with the other (dry) end of the cotton bud, repeat with a second bud, then put disk in and "its a miracle" disk now reads !

If there is a pressure pad on top, keep it clear of the IPA, if there is a second R/W head on top you have a double sided drive.

If the disks have the dreaded mold condition on them then your out of luck sorry :wink:
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Re: Floppy problem on 80286 machine

Postby tezza on Sun Feb 23, 2014 1:28 pm

RonTurner wrote:If the disks have the dreaded mold condition on them then your out of luck sorry :wink:

Although as a last resort to get data off, washing the disks can work.
http://www.classic-computers.org.nz/blo ... -water.htm

I did this with some Kaypro disks also and retrieved almost everything!
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Re: Floppy problem on 80286 machine

Postby Columbo on Sun Feb 23, 2014 4:23 pm

Thank you for the responses guys.
I tried the "format a: /f:360" and got the same error. The original floppy that is in the machine is a Teac FD-55BR 102-U which I believe is a 360K floppy but I could be wrong. I also tried a new Panasonic JU-475-5 made by Matsushita and got the same errors. As previously mentioned, I get the same errors on the 3.5" floppy as well. While not impossible, I didn't think both drives would have the same problem. I tried using a new 3.5" drive and still get the same errors.
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Re: Floppy problem on 80286 machine

Postby RonTurner on Sun Feb 23, 2014 4:48 pm

You are getting the error because a Panasonic JU-475-5 is a High Density drive and you are trying to format a Double
Density disk in it, the two are incompatible.

I would try and clean the R/W head in the original drive and re-install that one and try the disks again, any patchy
spots on the disk ? im assuming the disk has the center ring ?

Same with the 3.5 inch drive, you are probably mixing your densities, they use stronger magnetic flux.

Make sure you have cleaned the R/W heads before you continue... you will need to unscrew the circuit
board to get to the R/W head
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Re: Floppy problem on 80286 machine

Postby Columbo on Sun Feb 23, 2014 5:45 pm

I tried cleaning the heads. Actually, I was incorrect on the Read error. Rather than a General Read error, I am getting a Sector Not Found error. A friend had a floppy from an old Toshiba from a 80286 that we tried in this machine. It had no stickers on it so the only number that I could see on it was on the PC board which says CGMK-77X. Anyway, we hooked it up, put one of my Clipper disks in and tried to do a DIR and got the same Sector Not Found error. I tried a different floppy ribbon cable and still the same. I'm not getting any error from the FDD controller card. So that's two old 80286 floppies and one 3.5" floppy that are all giving me the same error. What are the odds that all three are faulty? The disks are brand new 3M from a sealed box and I tried a couple of different ones so I don't think that there are any spots on them. Starting to get a bit frustrated.
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Re: Floppy problem on 80286 machine

Postby RonTurner on Sun Feb 23, 2014 9:04 pm

Did you have the BIOS set to 1.2mb(HD) and a HD drive plugged in with HD disk in the drive ?

Im assuming your clipper disks have a hubring, they wont load in your panasonic drive

If your BIOS is set to 360K and you have the panasonic plugged in it shouldn't work.

Image

you haven't said what density the disks are ? identify the density of the disks and drives and set the BIOS correctly
making sure they all match up.

some drives have jumpers and you can change the density etc.
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Re: Floppy problem on 80286 machine

Postby Gibsaw on Mon Feb 24, 2014 12:09 am

To use existing DSDD media, the TEAC is definitely what you should use. Set the drive to 360k in BIOS and you shouldn't have to specify anything on the format command. You'll get the same error on the 3.5" if it's set incorrectly in BIOS and similar problems with media density.

Moving forward, this is what I would do. Forgive the level of detail. It's simpler to be pragmatic.

1. Since you have them. Use the 360k TEAC, with DSDD (360k) media.
2. Clean the drive with ISO... Dry the heads with a cotton bud and then go make a coffee to let them dry properly. ISO will cause problems if not dry.
3. Doublecheck the orientation of the FDD cable. A consistently on FDD drive light is a (bad) problem. The controller end is usually the problem as the drive end is usually a keyed edge connector.
4. Make sure the drive plugged is into the correct connector as drive A: I've seen it vary which connector is which, and also make sure the controller/cable isn't one of those funny ones with the drive order jumpered. If it is, you'll need the correct single-floppy cable. Normal non-jumpered two-drive cables have a small partial twist in them.
5. Set the BIOS to 360k.
6. Visually check the media. Physically hold the disk in one hand, gently rotate the centre ring and examine the surface on both sides for mold. If mold has gotten in the pack, then it's highly likely that 80% will have problems.
7. If there is mold, get some clean media.
8. If I still get problems, get some DSHD media and start back at (1) with the panasonic and with BIOS set to 1.2M.
9. You could also re-try the 3.5" - again, set the drive type correctly and use the right media. Does the BIOS support 1.44M? Try a more modern vanilla matsushita/panasonic 1.44M?

If you can't get any traction, then we need to look at the controller. If it seems to be booting the hard disk ok, then the mainboard is probably ok. (for now.)

Then, we move to the disk controllers? MFM/RLL? IDE? Separate floppy controller or integrated? You mentioned a replacement FDD controller. Is there a new integrated HDD/Floppy controller in addition to a (dead) existing one? Maybe a conflict? Make sure the other FDD controller is properly disabled if it's still there.
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Re: Floppy problem on 80286 machine

Postby Columbo on Mon Feb 24, 2014 1:47 am

The CMOS was set to 360K. A consistently on FDD drive light is usually an indication of the cable being reversed but I have checked the cables and the ground is on pin 1. The hard drive has it's own controller card and has not given any problems. The cable is the type with the twist and I have drive a: after the twist. I inspected the disks and I don't see any indication of mold. The BIOS does support 1.44M and I tried a brand new Sony MPF-920 3.5" drive but same problem. I'll go over everything again and report back. Thanks for the suggestions.
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Re: Floppy problem on 80286 machine

Postby SpidersWeb on Mon Feb 24, 2014 7:02 am

DD disks will work in HD drives. But the BIOS must be set to "1.2Mb".
It'll use a 300kbps bit rate to compensate for drive rpm changes, and double step the drive when DD media is used.

The only pain in the ass, is that the head is narrower. So you can get read errors on DD drives if exchanging data back-and-fro with a HD drive. But I regularly use Panasonic and Teac 1.2Mb drives to read and write DD disks - both 48 and 96tpi. My Teac 1.2 is actually pretty astonishing at recovering bad 360Kb disks as well and has a soft loading head.

If it was set to 360KB, and 360KB media was used - a 1.2Mb drive would fail to double step - causing a read error on the second, fourth, sixth, eighth tracks etc

To eliminate firmware/hardware, pop that 3.5" floppy in another machine, format it 1.44Mb and make it a boot disk (can get MS DOS boot disk images on the net). Then pop it back in the 286 with the BIOS set to 720. It should, despite the wrong setting, still boot up off your floppy. If not, then something really funky is going on.

Besides what has already been said and making sure everything is perfect each time (including drive head cleans - do not underestimate this one) - my only recommendation on the topic is to find a way to install Dave Dunfield's ImageDisk / IMGDISK on the 286. This controls the hardware directly, and lets you write/read/seek to whatever track you want as well as image disks to make duplicates. This tool with 5.25" drives was a godsend for me because you can actually see what's going on.

e.g. if T0 H1 shows data, but T0 H0 shows nothing - then one of the heads is likely dirty (or damaged - worst case), if T0 does not read but T1-39 do - then chances are the disk has had Track 0 scratched off, if high tracks read but low tracks wont then alignment etc etc etc
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Re: Floppy problem on 80286 machine

Postby Gibsaw on Mon Feb 24, 2014 10:43 am

SpidersWeb wrote:Besides what has already been said and making sure everything is perfect each time (including drive head cleans - do not underestimate this one) - my only recommendation on the topic is to find a way to install Dave Dunfield's ImageDisk / IMGDISK on the 286. This controls the hardware directly, and lets you write/read/seek to whatever track you want as well as image disks to make duplicates. This tool with 5.25" drives was a godsend for me because you can actually see what's going on.


This sounds like a great idea. Laplink cables are your friend if the 286 has a working serial or parallel port. You are already very lucky in that it has MS-DOS 6.2 installed, so you can use intersvr.
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Re: Floppy problem on 80286 machine

Postby Columbo on Mon Feb 24, 2014 6:57 pm

I've looked all over the internet for Dunfield's ImageDisk and while there is a lot of talk about it, I can't find any place where it can be downloaded. Is this a commercial product or GNU?

Thanks
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Re: Floppy problem on 80286 machine

Postby tezza on Mon Feb 24, 2014 8:56 pm

Look here under "Special Purpose Packages"
http://www.classiccmp.org/dunfield/dos/index.htm
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Re: Floppy problem on 80286 machine

Postby Columbo on Tue Feb 25, 2014 3:37 am

Thanks tezza.
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