What kind of Floppy controller is this?

[Lutiana]

So I finally got a better floppy controller for my XT and I installed a black 3.5" 1.44mb floppy drive. This makes getting data to and from it a lot easier.

So I now have a spare controller that looks it may actually be a bit more modern that what was standard on these things. I am not sure what it can hold and it looks to me as though it may have its own BIOS but seeing as it is so generic I am a bit stumped on information on it.

Anyone got one of these that can help me?

 

[paul]

Surely you need a BIOS-based controller anyway to get a 1.44 to work on a 5160 XT, no? What's your new controller?

I have a couple of other brands of this sort of thing - I'm guessing the single jumper is for the primary or secondary controller address and the 4-position jumpers are to select the combination of 360/1.2/720/1.44 drives on positions A and B.

Nice close-ups by the way!

 

[Lutiana]

I never even looked at the make/model of the new controller.

I was thinking something similar to what you said the JP2 block is probably for the type of drives.

I am guessing that since there appears to be a BIOS chip on this card (the one with the tape on it) that maybe JP1 is BIOS Enable/Disable, sound plausible?

I may just jumper it and slap it in and see what happens, I don't think I can damage anything, can I?

 

[modem7]

, I don't think I can damage anything, can I?

Only your reputation.

 

[per]

Nice close-ups by the way!

Some mid-end digital cameras today can even take clear pictures of objects as close as 1cm!

As for the card, its definely a floppy controller supporting drives up to (at least) 1.44Mb.

How come you needed a new fdd-controller to connect a 1.44Mb drive?

(In my cause, I got a HD FDD-Controller in my XT, but it's designed for AT-class machines so it doesn't got any BIOS extensions. Because of this, I can only use 720Kb formated disks with it.)

 

[Lutiana]

How come you needed a new fdd-controller to connect a 1.44Mb drive?

The "new" one had a list of settings attached, so I knew that it would support the 1.44mb drive. This one does not. I simply opted for the known entity instead of the unknown one.

I will have to experiment with this one to verify if my thinking about the jumper settings is accurate.

 

[Chuck(G)]

The first thing that caught my eye was the single 16MHz crystal. Right off the top I'll say that there's no way this card will support single-speed (the usual case) 1.2MB floppies. (the data rate for 360K in a 1.2MB drive is 300Kbps, which is not a divisor of 16MHz. You usually see cards that support 1.2MB operation with two crystals--something like 8MHz and a 9.6 MHz, or a single 24MHz crystal.

The 83C765 appears to be SIS's version of the NEC uPD 765 at first blush, which puts the support logic in the 83C66 flatpack and traces seem to bear this out.

There's a possibility that this card might support 1.44MB drives, but not 1.2MB. An examination of the BIOS will tell a lot.

Otherwise, I'm guessing that J1 may determine the port (primary=3Fx, secondary=37x) and the jumpers may be drive type or BIOS ROM base address.

 

[Lutiana]

Otherwise, I'm guessing that J1 may determine the port (primary=3Fx, secondary=37x) and the jumpers may be drive type or BIOS ROM base address.

Your probably right, the only thing is, if there is a BIOS on that card it is currently disabled somehow since it there was not messages at POST about floppy drives. This is why I am thinking that JP1 is a BIOS enable/disable.

But, I won't know till I try. Hopefully I will get a chance tonight.

 

[diodenmann]

I recently got a NOS bunch of these controllers. Instead of GDC-66 it reads TN-860C on the back but it's the same card.

Can you tell me what kind U5 and U7 are of ?

According to the original manual, I can provide some information:

JP1: PC or PS/2 reduce write current selector

1-2 Select PC/XT or AT
2-3 Select PS/2

SW1:
1 2 3 4
on off on on XT
on off on on AT with HDC installed
off off on on AT without HDC
on off off off PS/2

The manual also mentions explicit support of 360k, 720k, 1.2M and 1.44M drive types.

Are you able to make an image of the onboard rom ?

 

[Lutiana]

I don't have the card anymore, I sold it to OffensiveJerk on this forum, so you may want to PM for the answers to your question.

Sorry I could not be of more help.

 

[Raven]

I recently got a NOS bunch of these controllers. Instead of GDC-66 it reads TN-860C on the back but it's the same card.

Can you tell me what kind U5 and U7 are of ?

According to the original manual, I can provide some information:

JP1: PC or PS/2 reduce write current selector

1-2 Select PC/XT or AT
2-3 Select PS/2

SW1:
1 2 3 4
on off on on XT
on off on on AT with HDC installed
off off on on AT without HDC
on off off off PS/2

The manual also mentions explicit support of 360k, 720k, 1.2M and 1.44M drive types.

Are you able to make an image of the onboard rom ?

You selling? An 8-bit FDC that can handle 1.44MB sounds like a handy thing to have around.

 

[Chuck(G)]

The manual also mentions explicit support of 360k, 720k, 1.2M and 1.44M drive types.

And that could well be true--but I'm pretty sure you won't be able to read 360K diskettes in a 1.2MB drive unless that drive is set up for dual-speed operation. It's that 300Kbps data rate that causes problems.

 

[ZOBEX]

Here is a pic of a similar card (sorry but my digital camera is about as old as an XT). This one supports FOUR floppies at one time and all four formats, 360-720-1.2-1.44 and can support any combination on any cable. So you can run a 360 and a 1.44 on the same ribbon cable. The selector switch sets the type of each individual drive and the jumper sets it as primary and secondary drive card. I recall in the past I ran this card parallel to an original 360k floppy card with the internal card edge and a external port on the back for an external floppy. Also at one time ran four 360k floppies at one time in a flip top case.

I was considering running this card for an inside 1.44 and a USB drive then using the early 360k card to port out the back to an 8" floppy drive. Just another idea.

 

[Chuck(G)]

The 360K card probably won't do FM or support the 500K data rate of an 8" drive without serious modification.

You're better off using the 4 port card with everything (it will do 360K in a 1.2M drive--the crystal is 24MHz).

 

[tipc]

be advised the *765 on that one chip is a giveaway. It's a clone of NEC's pd765. Years ago the floppy subsystem failed in my tandy 2000. It used an intel 8272a, also an NEC clone. That much I knew. I also owned an ITT Xtra XP, which had a theretofore unknown 6765 floppy controller by Rockwell. It took me a while but then it dawned on me. It worked like a charm in the 2000.

 

[Chuck(G)]

Other than the "non-controllers" like the Catweasel and the Central Point Option Board, aren't all ISA-bus floppy controllers basically 765/8272? If that's not true, I've never run into a case that breaks this rule of thumb.

It doesn't really matter what you call it, or even if it's buried in a corner of someone's southbridge chip, it's all the same backward 1979-era 765. Even parallel-port and USB drives still have the 765 somewhere in the silicon. You have to go completely outside of the IBM PC world to find something else (e.g. Apple, Commodore, Atari).

I've got an ISA controller that uses a WD1772, but it's strictly a one-off prototype. I think the Mitsubishi MBC-500 series used a WD chip, but it's not on an ISA bus and calling the MBC-5xx a "PC Compatible" is really stretching the definition.

 

[tipc]

you're essentially correct I suppose.

my NEC APC (the original 85 lb monster) uses 8" disk drives. It comes w/a floppy controller board containing an NEC pd765. Also have an aftermarket external set of 5 1/4" drives (by the world reknowned firm Butler Flats Associates) controlled by a WD1771 or 1772 (can't remember off hand). Go figure. You'd think it would be the other way around. And to my knowledge the 8" drives can store up to 1024k or 1280k of data.

 

[Robin4]

Does any one have the bios rom from this card? Because i have to same card, and i like that it could work with 1.44 MB floppy drives.

Thank you if you could help me out!!

Iam also make them shareable to other people..

 

[Robin4]

I recently got a NOS bunch of these controllers. Instead of GDC-66 it reads TN-860C on the back but it's the same card.

Can you tell me what kind U5 and U7 are of ?

According to the original manual, I can provide some information:

JP1: PC or PS/2 reduce write current selector

1-2 Select PC/XT or AT
2-3 Select PS/2

SW1:
1 2 3 4
on off on on XT
on off on on AT with HDC installed
off off on on AT without HDC
on off off off PS/2

The manual also mentions explicit support of 360k, 720k, 1.2M and 1.44M drive types.

Are you able to make an image of the onboard rom ?

Diodenmann do you still have a copy of that manual ? Is there any chance to scan it to PDF document?

 

[Robin4]

I recently got a NOS bunch of these controllers. Instead of GDC-66 it reads TN-860C on the back but it's the same card.

Can you tell me what kind U5 and U7 are of ?

According to the original manual, I can provide some information:

JP1: PC or PS/2 reduce write current selector

1-2 Select PC/XT or AT
2-3 Select PS/2

SW1:
1 2 3 4
on off on on XT
on off on on AT with HDC installed
off off on on AT without HDC
on off off off PS/2

The manual also mentions explicit support of 360k, 720k, 1.2M and 1.44M drive types.

Are you able to make an image of the onboard rom ?

Do you still have those manuals diodenmann? Can you scan one for an online version?