VOGONS


First post, by TSG

User metadata
Rank Newbie
Rank
Newbie

Made an account just for this because I can't actually find any help anywhere else.

I have a VT-503 Socket 7 motherboard with a Pentium MMX 200Mhz + 128MB RAM. Everything works fine except the serial connections on the board do not function at all. I tried five different sets of 9-pin ribbon cables and two mice. The board only has a 5-pin DIN keyboard connector, no PS/2.

Since the serial connections on board just absolutely refuse to work (I suspect it's a hardware problem, but I have no way to diagnose) , I got a Lava Computers Dual DB9 ISA card as a workaround. I disabled the onboard connectors in the BIOS (Award 1995 if that matters) and set the jumpers on the card to use COM1, IRQ 3 and COM2, IRQ 4 in their place.

The BIOS, Snooper, and all other programs detect the ports correctly. I plug up my mouse and run Microsoft Mouse 9.01. The mouse is detected and it lets me install drivers (MS-DOS only for now) but in the Mouse Manager settings menu, where you can test the mouse, I cannot move the cursor at all.

I tried my other mouse and also tried them both under WfW 3.11. Same result, everything detects there is a mouse connected, but I cannot move the cursor no matter what. Baud rate? Could the ISA card be bad? The motherboard itself?

Any help would be appreciated.

Reply 1 of 11, by evasive

User metadata
Rank Oldbie
Rank
Oldbie

In windows you need to separatley set the mouse again for microsoft mouse or mouse systems mode or something.

As for the ribbon cables, did you check if you actually have both kinds? You need to check the back of the DB9 connector to see how the wires go.

The headers can be either

1 3 5 7 9
2 4 6 8
or
1 2 3 4 5
6 7 8 9

Reply 3 of 11, by TSG

User metadata
Rank Newbie
Rank
Newbie

All my ribbon cables are 12345 up top, 6789 on bottom. The serial ports on the ISA card are also the same pin layout.

The problem isn't just on Windows. I can't move the cursor on anything. I know it's not my mice because they both work fine on my 486, which has the same pin layout as the others.

Reply 4 of 11, by weedeewee

User metadata
Rank Oldbie
Rank
Oldbie
TSG wrote on 2021-04-14, 14:05:

All my ribbon cables are 12345 up top, 6789 on bottom. The serial ports on the ISA card are also the same pin layout.

The problem isn't just on Windows. I can't move the cursor on anything. I know it's not my mice because they both work fine on my 486, which has the same pin layout as the others.

That is exactly what might be the problem. Being that your cables are 12345 up top and 6789 on bottom.

You could try to rewire one cable to have 13579 on top and 2468 on bottom, or purchase one.

Reply 5 of 11, by TSG

User metadata
Rank Newbie
Rank
Newbie
weedeewee wrote on 2021-04-14, 14:09:

That is exactly what might be the problem. Being that your cables are 12345 up top and 6789 on bottom.

You could try to rewire one cable to have 13579 on top and 2468 on bottom, or purchase one.

I'm not using the cables. I've disabled the onboard serial to use the ISA card instead.

I saw where someone was having a similar problem to mine and the solution was only a specific Logitech driver would work. I'm going to try that same driver.

Reply 7 of 11, by TSG

User metadata
Rank Newbie
Rank
Newbie
weedeewee wrote on 2021-04-14, 14:40:

in the first post you say com1 irq 3 ... are you sure about that ? because normally... com1 is irq 4

I'm pretty sure. The ISA card has jumpers you set by hand for IRQ# and COM#. Not sure why you would need to go all the way to COM6, but it does.

IMG_20210414_104355674.jpg
Filename
IMG_20210414_104355674.jpg
File size
564.3 KiB
Views
95 views
File license
CC-BY-4.0

Reply 8 of 11, by weedeewee

User metadata
Rank Oldbie
Rank
Oldbie

You could even go to COM8.
But that's beside the point
Thing is...
COM1 - 0x3F8 IRQ 4 <- this is default... unless the mouse driver is set to use IRQ3. It will, by default, try to use IRQ4 .
so your onboard ports might not work due to a cabling error, your add-on card probably doesn't work due to an IRQ error...

Reply 9 of 11, by TSG

User metadata
Rank Newbie
Rank
Newbie
weedeewee wrote on 2021-04-14, 14:56:

COM1 - 0x3F8 IRQ 4 <- this is default... unless the mouse driver is set to use IRQ3. It will, by default, try to use IRQ4 .
so your onboard ports might not work due to a cabling error, your add-on card probably doesn't work due to an IRQ error...

Ok I changed the jumpers to IRQ4 on COM1. If this works i'm going to feel mighty stupid.

EDIT: It works! Thanks for pointing that out. I would have been stuck for eternity.

Reply 10 of 11, by weedeewee

User metadata
Rank Oldbie
Rank
Oldbie

Huray again !

Now if you ever feel like checking the onboard ports...
if you look at the DB9 connector and measure between top right pin ( pin5, GND) and your mainboard GND (any ground pin, black wires on power connector)
( This is offcourse with the DB9 cable connected to the mainboard, on the correct pinheader and in the right orientation )
You should have 0 ohm or continuity beep and close to zero indication.
If not, the layout is incorrect and you'll find it on another pin of the DB9 which will give a clue as to what layout is the correct one.