Don't have any ideas yet on the board, but I think that the PSU and drive(s) used should be added to the suspect list also.

BitWrangler wrote on 2021-08-13, 21:56:

Don't have any ideas yet on the board, but I think that the PSU and drive(s) used should be added to the suspect list also.

I've tried multiple drives and none worked, but haven't checked the PSU. Could it be delivering too much voltage?

Or too much ripple. AC superimposed on the DC

BitWrangler wrote on 2021-08-13, 22:09:

Or too much ripple. AC superimposed on the DC

Wouldn't other cards/components be affected as well? I have an xt-ide card, vga card, and an adlib card in it and all of them seem to be working fine. How can i test it that's the case?

f34rthereaper wrote on 2021-08-13, 23:33:

BitWrangler wrote on 2021-08-13, 22:09:

Or too much ripple. AC superimposed on the DC

Wouldn't other cards/components be affected as well? I have an xt-ide card, vga card, and an adlib card in it and all of them seem to be working fine. How can i test it that's the case?

Yes the PSU could be the issue but my feelings also look to you not diagnosed your main board to the point of knowing it fully.
Your board picture is a postage stamp. Can you take a better one ? You can attach up to 1MB images here without a problem.
Can you list all the exact cards you have installed ? Using: "xt-ide card, vga card, and an adlib card" is too generic to actually understand what you have for troubleshooting purposes.
Have you tried an original 8 bit floppy controller without the XT-IDE to see what happens ? ...Just some thoughts....

Horun wrote on 2021-08-14, 02:39:

Yes the PSU could be the issue but my feelings also look to you not diagnosed your main board to the point of knowing it fully. […]
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f34rthereaper wrote on 2021-08-13, 23:33:

BitWrangler wrote on 2021-08-13, 22:09:

Or too much ripple. AC superimposed on the DC

Wouldn't other cards/components be affected as well? I have an xt-ide card, vga card, and an adlib card in it and all of them seem to be working fine. How can i test it that's the case?

Yes the PSU could be the issue but my feelings also look to you not diagnosed your main board to the point of knowing it fully.
Your board picture is a postage stamp. Can you take a better one ? You can attach up to 1MB images here without a problem.
Can you list all the exact cards you have installed ? Using: "xt-ide card, vga card, and an adlib card" is too generic to actually understand what you have for troubleshooting purposes.
Have you tried an original 8 bit floppy controller without the XT-IDE to see what happens ? ...Just some thoughts....

I apologize for the bad image, i'm away from my house and that was the best i could find that matched my board. I'll post a higher res one tomorrow. Here's a little higher res image from the ebay listing i was able to dig up for now attached

ISA cards i have in the system-

• XT-IDE isa card by blue lava systems
  

• Resound 2 OPL3 adlib card
  

• Oak Technology OTI 067c vga card

And i did try without the xt-ide in and that didn't make any difference. Also tried the 8bit floppy controller out of my xt and that worked fine, booted and read disks fine.

f34rthereaper wrote on 2021-08-13, 22:08:

BitWrangler wrote on 2021-08-13, 21:56:

Don't have any ideas yet on the board, but I think that the PSU and drive(s) used should be added to the suspect list also.

I've tried multiple drives and none worked, but haven't checked the PSU. Could it be delivering too much voltage?

The idea of "adding the drives to the suspect list" doesn't mean that we suspect the broken card would work with different drives, but instead, the drive(s) could be what killed the card. Drives have a +12V connection that could enter the floppy controller through the floppy interface cable if the drive is broken. 5V chips don't like 12V on their inputs and might break. What kind of drives are installed in your machine?

On the other hand, the card seems to have three sections: The floppy controller, the BIOS and the serial port. Broken drives would kill the floppy controller section, not the BIOS section. If you enter "d C800:0" in DEBUG (replace C800 with the base address of your floppy BIOS), do you still see something except FF ?

Ah, that makes sense! I have it loaded at 0xf2000, when i run debug I the output is a repeating string of ......<. Guess that means there's nothing loaded in that space? I looked in checkit as well, and can confirm that is a free space of memory

f34rthereaper wrote on 2021-08-14, 13:20:

Ah, that makes sense! I have it loaded at 0xf2000, when i run debug I the output is a repeating string of ......<. Guess that means there's nothing loaded in that space? I looked in checkit as well, and can confirm that is a free space of memory

I can't make sense of the string, as debug uses the "." as replacement character for everything unprintable. The hex bytes before the dots are more informative, but I guess they are indeed FF FF FF FF FF FF FF FF - FF FF FF FF FF FF FF FF which means that the ROM is not responding.

At Address F200:0 (or F2000 linear), the ROM can not work in most machines newer than the XT, because the complete F000-FFFF range is reserved for the mainboard BIOS. Sometimes (in late 486 and Pentium systems nearly always), the E000-EFFF range is also occupied, so your test in the 486 computer shows that the FDC still works, but does not tell you anything about the BIOS part, unless you changed the address. Using address DE00 should be universally compatible with all computers, unless another extension BIOS already occupies that address.

I don't know your XT mainboard well enough to be able to tell whether that board supports ROMs in the F000 range on the XT bus, or it just "works or doesn't work as you are lucky", possibly due to addressing conflicts. It's possible that it is temperature dependant whether a ROM that is involved in an address conflict is accessible or not.

I looked at the schematics of your card (as it is open-source hardware), and the ROM interface looks so straightforward that I have no idea how anything could kill just the ROM interface on that card - especially as you tested the ROM as good. One idea is that maybe the +5V on that card is flaky, and the ROM, which actually is an EEPROM, is very picky about stable +5V supply to prevent spurious writes.

mkarcher wrote on 2021-08-14, 14:50:

I can't make sense of the string, as debug uses the "." as replacement character for everything unprintable. The hex bytes befor […]
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f34rthereaper wrote on 2021-08-14, 13:20:

Ah, that makes sense! I have it loaded at 0xf2000, when i run debug I the output is a repeating string of ......<. Guess that means there's nothing loaded in that space? I looked in checkit as well, and can confirm that is a free space of memory

I can't make sense of the string, as debug uses the "." as replacement character for everything unprintable. The hex bytes before the dots are more informative, but I guess they are indeed FF FF FF FF FF FF FF FF - FF FF FF FF FF FF FF FF which means that the ROM is not responding.

At Address F200:0 (or F2000 linear), the ROM can not work in most machines newer than the XT, because the complete F000-FFFF range is reserved for the mainboard BIOS. Sometimes (in late 486 and Pentium systems nearly always), the E000-EFFF range is also occupied, so your test in the 486 computer shows that the FDC still works, but does not tell you anything about the BIOS part, unless you changed the address. Using address DE00 should be universally compatible with all computers, unless another extension BIOS already occupies that address.

I don't know your XT mainboard well enough to be able to tell whether that board supports ROMs in the F000 range on the XT bus, or it just "works or doesn't work as you are lucky", possibly due to addressing conflicts. It's possible that it is temperature dependant whether a ROM that is involved in an address conflict is accessible or not.

I looked at the schematics of your card (as it is open-source hardware), and the ROM interface looks so straightforward that I have no idea how anything could kill just the ROM interface on that card - especially as you tested the ROM as good. One idea is that maybe the +5V on that card is flaky, and the ROM, which actually is an EEPROM, is very picky about stable +5V supply to prevent spurious writes.

Sorry about that! at that area it was more or less a repeating string of 36 and 00. I dumped the bios of the card, and compared it in a hex editor and the beginning area was nothing alike.

For a control I plugged it into my 5160 and ran debug to see what was loaded in the address space of the floppy card and got the same result. That's what i find most baffling- there's not a whole lot that can go wrong with these cards. Guess i can try replacing the few components there are

f34rthereaper wrote on 2021-08-14, 15:19:

Sorry about that! at that area it was more or less a repeating string of 36 and 00. I dumped the bios of the card, and compared it in a hex editor and the beginning area was nothing alike.

For a control I plugged it into my 5160 and ran debug to see what was loaded in the address space of the floppy card and got the same result. That's what i find most baffling- there's not a whole lot that can go wrong with these cards. Guess i can try replacing the few components there are

Repeating 36 and 00 would mean something responds on that card. The 5150 and 5160 mainboards use TTL logic, and TTL inputs should always read FF if nothing responds. You should do a counter-check that you read FF at that position if the card is not installed - otherwise choose a different address. The only component that can be responsible to deliver only 36 and 00 instead of the real data is the EEPROM itself. The address lines and data lines are wired from the bus straight into the EEPROM.

mkarcher wrote on 2021-08-14, 16:08:

f34rthereaper wrote on 2021-08-14, 15:19:

Sorry about that! at that area it was more or less a repeating string of 36 and 00. I dumped the bios of the card, and compared it in a hex editor and the beginning area was nothing alike.

For a control I plugged it into my 5160 and ran debug to see what was loaded in the address space of the floppy card and got the same result. That's what i find most baffling- there's not a whole lot that can go wrong with these cards. Guess i can try replacing the few components there are

Repeating 36 and 00 would mean something responds on that card. The 5150 and 5160 mainboards use TTL logic, and TTL inputs should always read FF if nothing responds. You should do a counter-check that you read FF at that position if the card is not installed - otherwise choose a different address. The only component that can be responsible to deliver only 36 and 00 instead of the real data is the EEPROM itself. The address lines and data lines are wired from the bus straight into the EEPROM.

I tried the equally non-functioning floppy controller that was sent as a replacement for the first, and set the address to 0xf0000 and plugged it into my xt 5160. I can see the rom being loaded with the DEBUG command, and the sequence identical to what i see when i load the bios in a hex editor on my pc. It seems like it's loaded, but isn't. You're supposed to be able to enter the config menu for the card by hitting f2 on boot, but that doesn't work even with the xt-ide removed(same card as in my turbo xt clone). When i plug known good 3.5" floppy drive into it and pop a floppy disk in it cannot read it, but I hear the motor spin and the act light on the drive comes on. When i try formatting the disk inserted, it fails and think the disk a 360k disk rather than a 1.44mb. Usually the controller is pretty good at auto-detecting drive type and you're supposed to be able to set the drive type in the settings menu i mentioned earlier.

f34rthereaper wrote on 2021-08-14, 17:55:

I tried the equally non-functioning floppy controller that was sent as a replacement for the first, and set the address to 0xf0000 and plugged it into my xt 5160. I can see the rom being loaded with the DEBUG command, and the sequence identical to what i see when i load the bios in a hex editor on my pc. It seems like it's loaded, but isn't.

Most XT BIOSes I've seen do not recognize ROM extensions in the F segment, even if the mainboard can access ROMs at that address via the ISA bus. Try changing the ROM base to a lower address.

mkarcher wrote on 2021-08-14, 18:00:

f34rthereaper wrote on 2021-08-14, 17:55:

I tried the equally non-functioning floppy controller that was sent as a replacement for the first, and set the address to 0xf0000 and plugged it into my xt 5160. I can see the rom being loaded with the DEBUG command, and the sequence identical to what i see when i load the bios in a hex editor on my pc. It seems like it's loaded, but isn't.

Most XT BIOSes I've seen do not recognize ROM extensions in the F segment, even if the mainboard can access ROMs at that address via the ISA bus. Try changing the ROM base to a lower address.

Making progress! Looks like the bios is being loaded now, and i can enter the config menu. Still can't boot or read disks though, and tried a few different drives and cables. when i try reading a drive in dos it fails wit the fail, abort, and retry. I tried formatting a brand NOS floppy disk and fails saying that sector 0 is bad. Same thing happens with multiple disks. Tested everything i said in both my xt and turbo-xt

f34rthereaper wrote on 2021-08-15, 00:25:

I tried formatting a brand NOS floppy disk and fails saying that sector 0 is bad.

Does it say "sector 0" or "track 0" is bad? If the error mentions "track 0" then the issue could be the track 0 sensor in the drive not working or the ribbon cable/connector could have a bad connection on the track 0 detect wire/pin.

f34rthereaper wrote on 2021-08-15, 00:25:

Making progress! Looks like the bios is being loaded now, and i can enter the config menu. Still can't boot or read disks though, and tried a few different drives and cables. when i try reading a drive in dos it fails wit the fail, abort, and retry. I tried formatting a brand NOS floppy disk and fails saying that sector 0 is bad. Same thing happens with multiple disks. Tested everything i said in both my xt and turbo-xt

OK, so the BIOS portion of the replacement controller is working correctly. Maybe the floppy controller chip itself is bad. Does the replacement controller read floppy disks in your 486 computer? Did you consider that maybe your PC/XT computers were stored in a dusty place and possibly all drives that were stored with them might have dirty heads? Do you have a multimeter to verify that the +12V from your power supply is OK (although it would be surprising if both the XT and the PC have malfunctioning +12V supply)?

kdr wrote on 2021-08-15, 02:33:

f34rthereaper wrote on 2021-08-15, 00:25:

I tried formatting a brand NOS floppy disk and fails saying that sector 0 is bad.

Does it say "sector 0" or "track 0" is bad? If the error mentions "track 0" then the issue could be the track 0 sensor in the drive not working or the ribbon cable/connector could have a bad connection on the track 0 detect wire/pin.

mkarcher wrote on 2021-08-15, 06:52:

f34rthereaper wrote on 2021-08-15, 00:25:

Making progress! Looks like the bios is being loaded now, and i can enter the config menu. Still can't boot or read disks though, and tried a few different drives and cables. when i try reading a drive in dos it fails wit the fail, abort, and retry. I tried formatting a brand NOS floppy disk and fails saying that sector 0 is bad. Same thing happens with multiple disks. Tested everything i said in both my xt and turbo-xt

OK, so the BIOS portion of the replacement controller is working correctly. Maybe the floppy controller chip itself is bad. Does the replacement controller read floppy disks in your 486 computer? Did you consider that maybe your PC/XT computers were stored in a dusty place and possibly all drives that were stored with them might have dirty heads? Do you have a multimeter to verify that the +12V from your power supply is OK (although it would be surprising if both the XT and the PC have malfunctioning +12V supply)?

So, one of the cards seems to be working fully now! I dug around "the box" and found another floppy cable and that seems to work with the card. The bios is loaded, and i can boot/read disks with it on both my xt and turbo board. The other loads the bios and seems to detect a drive and try to read a disk but i get the abort, fail, retry and when i try formatting it i get the error about track 0 being bad; this is with the exact same cable and drive that works fine with the other controller. One of the drives i tried is a gotek floppy emu, which i know can be spotty with this old tech, but at the very least it rules out any mechanical/media issues and it works fine with the other controller I mentioned. I did try swapping the chips out, and the bad card was still bad and the good card was still good.

I really appreciate the help btw!

f34rthereaper wrote on 2021-08-15, 18:52:

So, one of the cards seems to be working fully now!

I did try swapping the chips out, and the bad card was still bad and the good card was still good.

If you want to further troubleshoot the bad card, please test whether the serial port on the bad card is working. If you can return the bad card to the store, you might just do so, though.