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Compaq 386 - floppy drive and GOTEK woes

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solidpro

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May 14, 2020
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Hi All

I've got a bunch of Compaq Portable III and 386 machines which I am trying to make usable again. It seems that the III was a 286 which tended to come with 5.25" floppy drives and a hard disk. The 386 came later with a bigger hard disk and usually a 720k 3.5" floppy.

The machines do not have a built in BIOS - you have to configure everything via a boot disk and then save it. Without the boot disk and a dead CMOS you're kinda dead in the water.

All of my 3.5" drives are dead. I might be able to strip them down but I don't have any 720k floppies anyway. Now, I have a working 5.25" drive which I can use on these machines to boot from into the Compaq diag tools.

So I've seen online other people have got these machines working with a Gotek/flashfloppy USB emulator. I have 3 of these on the shelf, so that's what I'm trying. Others don't seem to have had any issues.

The 5.25 'ribbon' (with a crossover in it) goes to some kind of daughterboard (with molex power) which in turn presents the smaller 3.5" type of connectors (power and data).

Anyway, it's close to working. I added a bunch of image files to my flashfloppy (which has a display) for 360k, 720k 1.2mb and 1.44mb boot disks for things like compaq, dos, windows, etc. Nothing works.

The machine powers on, the gotek light flashes for the CMOS test (like normal) then the machine tries to seek/boot and it just flickers between sector 0 and complains.

I tried booting with my 5.25" drive and changing the default drive A from 360k to 1.44mb and it makes no difference.

I think it's something to do with the connector and the crossover in it. Has anyone got any ideas of things to try? I don't have any other floppy cables, so I'd likely have to buy them.

Thanks
 
Sadly, I can't shed light on your problems.

I can tell you that I had no trouble installing GOTEKs in my Compaq Portable III and 386 systems. They went in just fine and worked without problem.

The only "gotcha" is that if the BIOS expects a 360K disk, your disk image on the GOTEK must be a 360K disk image or it won't read it.
 
Is your gotek jumpered correctly? By default I don’t think they come set for IBM PC compatibility. It took me about 30 minutes of head scratching before I read the manual and added a missing jumper. This was on a generic 386, not a Compaq, but I’d imagine it would be the same.

Here is how mine is configured:

IMG_4756.jpeg
 
Er, yes, it's not at all clear what disk you're trying to use, you mention so many (too many).

As 'rlauzon' says (suggests) the Gotek system cannot do anything with the image but read it. So you MUST supply a correct image. As in a correct image of the same type and format that the computer is expecting, and trying to boot from. So, if the machine is trying to boot from a DSDD 720k 3.5" disk, then that is what you must provide. You also mentioned a 360k 5.25. These would be different images, with different files on. On the basis of what you said re using a 3.5" HD (1.44Mb) disk, this would NOT work (no hint that the machine supports that format).

If you've got the original drive, even though it's not working, you might study that to determine what that it and get that image. Cut out a bit of guess-work?

Geoff
 
These machines will only access the media as DD until the BIOS is set up. As such, 5 1/4 drives will be accessed as 360K and 3.5 drives will be accessed as 720K. Only once the BIOS has been set to use high density will it support 1.2 MB or 1.44 MB media.
 
So, need to start with images for either 360k or 720k. Your first message doesn't mention trying those? Will the machine autodetect either 5.25 or 3.5? If not, then use the one that it will accept immed.

Do you have an image of a suitable boot disk? FlashFloppy can be set to default to the HFE (??.hfe) image type, do you have that type of image file?

If the machine will 'boot', will it now do something without running the CMOS thing, or is this vital? This prog could initially be on a separate image, but once things are working in the right direction it could (space ok?) be on the same image?

Geoff
 
GeoffB17 said:
If the machine will 'boot', will it now do something without running the CMOS thing, or is this vital? This prog could initially be on a separate image, but once things are working in the right direction it could (space ok?) be on the same image?
Click to expand...

For these machines, there is no CMOS setup in ROM. You have to boot from a disk and run a setup program to change the CMOS settings.

And, of course, the battery is shot by now. So until the battery is replaced, the CMOS settings won't stay.
 
I vaguely recall at least some of the Compaq FDCs from this era expect dual-speed 5.25" drives (i.e. the drive switches from 360 RPM to 300 RPM based on density) instead of directly supporting the 300K/s data rate of a low density disk in a 360 RPM drive (250K/s at the normal 300 RPM for low density). It is possible the Gotek needs to be told to do this. It is also possible the Compaq FDC (if it is set up for a dual-speed 5.25" drive) can be re-configured to behave otherwise.

Foggy memory, but potentially something to double-check.

edit: probably that doesn't explain why the 3.5" formats don't work correctly, though, as they would always be 300 RPM, either 250K/s or 500K/s data rate.
 
Thanks everyone - I'm midway through a 10-machine restoreathon and I didn't have notification alerts onto this thread. I may well have the willpower to try again checking my Goteks tomorrow. I eventually reached the concensus that the best way forward was to adapt these machines to booting from IDE->CF and the ones with non-working floppy drives I've paid someone to service them all.

Funnily enough, about 4/5 machines have 5.25" drives which all work perfectly. The other 4/5 have 3.5" 720k drives and all of them have failed. Which is why I was trying to Gotek boot them!
 
Sorry, it's been a while. I want to say thanks to jafir because part of the problem was definitely my jumpers. That got me halfway there.

I couldn't find a source of the weird dallas clock chip anywhere (it's a low profile 4-terminal battery module - not a DS1287) anywhere, so I used PCBway to build my own. I'm going to build 50 of them and stick a bunch on ebay for anyone else who needs one. Anyway, that saga is also completed.

Thirdly, the Portable III/386 always seems to default to either 360k or 720k FDDs and even though I have both of these on my flashfloppy, it doesn't want to read them. So what I needed to do was use a 5.25" floppy drive and diagnostics boot disk to boot a machine with a working CMOS to set the drive to 1.44Mb and then reboot with the flashfloppy connected and we're in business. Can boot to DOS and Windows and all that kind of thing using 3.5" images.

Finally, I got some mounts 3D printed also from PCBway for the compact flash to sit in what was the covered HDD slot on the side. All I need to do is spray paint them and I'll be in business.

I'll probably end up with a couple of entirely original (FDD + HDD) machines booting and working, and then a bunch of modernised machine with a combination of real floppy, Goteks and 'factory finished' CFF drive bays, and I'll be ebaying some of them.

Thanks everyone so far. I might post some pictures next week when I'm a little closer to final assembly!
 
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