I would suspect the FDD controller but you said same problem with a different controller and FDD.

Given that it seems to me it's got to be something to do with a memory address that only affects floppy drives.
Perhaps a specific 'chunk' of RAM that holds the FDD's driver or handles communications to the FDD.
I'm not good with memory mapping. Hoping someone that is pops in.

Maybe try switching RAM and/or cache chips around to see if something changes.
.

When I got the PC, only 3.5" floppy drive was connected to the controller, but because I was more interested in having working 5 1/4 floppy drive I disconnected the 3.5" floppy drive and connected the 5 1/4" one before I even turned the computer on for the first time. When I first turned the computer on and saw how the directory listing was messed up on the floppy driver, my first assumption was that the 5 1/4" floppy drive was broken but when I connected the 3.5" floppy drive, the directory listing looked very similar. After that I switched the controller to another to see if that was not working properly, but changing it didn't change anything.

Another mystery is that if floppy drives are not working, how did the seller copy those programs for testing the computer on the hard drive before he sold me the computer since there is no optical drive or signs that the computer would have ever had one.

Did you change the settings for the FDD type in the BIOS?

The seller could have removed the drive and put it in a different machine to load it.
That's a common way to do it.

PCBONEZ wrote:

Did you change the settings for the FDD type in the BIOS?

The seller could have removed the drive and put it in a different machine to load it.
That's a common way to do it.

Yeah, I always changed the FDD types in bios when I changed drives while I was testing. The bios looks like it is specific to that motherboard instead of generic one like award or ami bios that most of my motherboards have.

PCBONEZ wrote:

He was talking about the time only.

I don't think the motherboard is bad either.
Maybe RAM, Cache, Cable.

I once had problems with (at least) the floppy. I tried to install dos and it always had read/write problems at the same file. Different cpu different file. I Turned of the cache in the bios and dos installed without a problem. Changed the cache and taddaaa everything works now.
Not really thje same problem but how about disableing the cache or removing it for testing...

Here is an easier to follow guide to that controller card.
https://amaus.net/static/S100/JUMPERS/total%2 … c/txt/20464.txt

McBierle wrote:

PCBONEZ wrote:

He was talking about the time only.

I don't think the motherboard is bad either.
Maybe RAM, Cache, Cable.

I once had problems with (at least) the floppy. I tried to install dos and it always had read/write problems at the same file. Different cpu different file. I Turned of the cache in the bios and dos installed without a problem. Changed the cache and taddaaa everything works now.
Not really thje same problem but how about disableing the cache or removing it for testing...

Actually that sounds pretty close to this problem.
I vaguely remember a similar situation but that was almost 25 years ago.

hm 25y ago, i was between the 386 i got from my brother and the dx4-100 i bought 😀

sorry for ot

edit: with "once" i meant i had this situation a few weeks ago...

I didn't mean to imply anything.
Your story reminded me of my experience with it but it was so long ago I don't remember the details.

I had a similar problem with floppy drives about year ago. I guess the thing is that I don't want the reason for the problem be same as it was back then. Back then I also had a psu that correct voltages and all and still it was that replacing the psu was what fixed the problem.
I don't have that many working AT PSUs that I was looking forward to getting another when I bought this pc, so I hope it isn't the same thing as it was back then.

I'm working with atx/at adapters...

McBierle wrote:

I'm working with atx/at adapters...

I am sure I am going to have to do something like that too some day.
There are some things I can try tomorrow like trying to find another floppy cable to try or unwrap the cmos battery that someone has modded to the dallas chip and see if I have replacement for that or try to connect another psu temporarily or perhaps trying to disable cache.

Baoran wrote:

PCBONEZ wrote:

Did you change the settings for the FDD type in the BIOS?

The seller could have removed the drive and put it in a different machine to load it.
That's a common way to do it.

Yeah, I always changed the FDD types in bios when I changed drives while I was testing. The bios looks like it is specific to that motherboard instead of generic one like award or ami bios that most of my motherboards have.

Wait. The board is an EISA board.

IIRC, EISA boards require a configuration utility on a bootable floppy for setting up the interface cards separately from the BIOS settings.

Changing BIOS settings without running the EISA configuration utility afterwards may mean the configuration the cards know doesn't match what the BIOS says...

yawetaG wrote:

Wait. The board is an EISA board. […]
Show full quote

Baoran wrote:

PCBONEZ wrote:

Did you change the settings for the FDD type in the BIOS?

The seller could have removed the drive and put it in a different machine to load it.
That's a common way to do it.

Yeah, I always changed the FDD types in bios when I changed drives while I was testing. The bios looks like it is specific to that motherboard instead of generic one like award or ami bios that most of my motherboards have.

Wait. The board is an EISA board.

IIRC, EISA boards require a configuration utility on a bootable floppy for setting up the interface cards separately from the BIOS settings.

Changing BIOS settings without running the EISA configuration utility afterwards may mean the configuration the cards know doesn't match what the BIOS says...

How does the bootable configuration floppy work when the card in question is the floppy controller?

yawetaG wrote:

Wait. The board is an EISA board. […]
Show full quote

Baoran wrote:

PCBONEZ wrote:

Did you change the settings for the FDD type in the BIOS?

The seller could have removed the drive and put it in a different machine to load it.
That's a common way to do it.

Yeah, I always changed the FDD types in bios when I changed drives while I was testing. The bios looks like it is specific to that motherboard instead of generic one like award or ami bios that most of my motherboards have.

Wait. The board is an EISA board.

IIRC, EISA boards require a configuration utility on a bootable floppy for setting up the interface cards separately from the BIOS settings.

Changing BIOS settings without running the EISA configuration utility afterwards may mean the configuration the cards know doesn't match what the BIOS says...

Does this apply when all the cards on eisa board are isa cards?

Edit: I ran eisa configuration utility on the hard drive. There was only options to change ram settings and add boards to each expansion slots if you have a .cfg file for that board.

~ Easter egging ~
If you have a plain ISA floppy controller install that and see if the problem reading the floppies goes away.
.

The controller has been just normal isa controller since I got the computer.

If it's not EISA they why do you need an EISA configuration utility?
At this point I'm getting lost.
I probably messed with EISA years ago but don't remember anything about EISA.
.
I do remember messing with VLB and that went so ~well~ I went out and bought a PCI mobo.
.

PCBONEZ wrote:

If it's not EISA they why do you need an EISA configuration utility?

You don't. Only for EISA cards. EISA is a 32-bit variant of ISA that was mostly used in high-end systems for companies. It is backwards compatible with the 16-bit and 8-bit ISA cards that were found in consumer systems.

The board has EISA connectors, which can take ISA or EISA cards. OP never mentioned the cards that were present were ISA...

At this point I'm getting lost. I probably messed with EISA years ago but don't remember anything about EISA. . I do remember me […]
Show full quote

At this point I'm getting lost.
I probably messed with EISA years ago but don't remember anything about EISA.
.
I do remember messing with VLB and that went so ~well~ I went out and bought a PCI mobo.
.

IMHO, it would be nice if the OP would give somewhat more information on the system. He only mentions what chipsets the two expansion cards have, not whether they are ISA or EISA. Do the cards have model numbers or a clear manufacturer name printed on them (or on stickers on the cards)? If so, what are they?
Has he tried replacing the CMOS battery yet? Some BIOSes don't function well with a dead or dying battery.
Has he tried reseating all cables, checked the cable orientation, or checking whether the floppy drives get power properly?

If the system worked for the seller, why doesn't Baoran ask the seller how he got it to work? If the seller meant the system worked before it was put away in storage 25 years ago, then who knows what might have happened to it in the time in between... 😐

I assume if I had eisa cards, they would need to be configured using the utility, but since I only have isa cards the eisa motherboard probably works like any other isa motherboard.