Dead com ports

**Garak** · September 2nd, 2002, 09:30 AM

PC-Chips M571 v.7.0 dead comm ports,

OK, this board has dead comm ports, but has a PS2 header (which I have fitted) Here what i need to know, would any of you sell a board on in kinda working order - ie the comm ports don't work as long as the end user is notified, I mean I don't really want to, its just a question as Socket 7 boards are hard to come by for a good price these days, I might build it into a server box with a 233mmx Intel, I don't yet know, please, no flaming, its a question nothing more.

Garak "I buy things cheap to play with and find out how they work"

**NooNoo** · September 2nd, 2002, 09:42 AM

Garak, I would remove the port headers and pop a pci card in there.... then there is no problem.

**freddy** · September 2nd, 2002, 10:30 AM

garry , my last p111 (jetway) board went the same way ,,,I bought a multi- board , most of the old shops that have been around since 486 days will have a few new one lying around , i paid a £5.

simply turn off the ide + floppy connections ,

now your question: yes , but i would inform customer .

serial mice/cameras etc are getting scares nowerdays ie: set it up with USB and the customer will love you.

cheers alan

FtF

**Garak** · September 2nd, 2002, 12:44 PM

Yeah, i was thinking something simular... thanks

**Ruslan** · September 2nd, 2002, 01:11 PM

First of all, are You really sure, what both of the COM ports are not working?
You see, there are at least two different incompatible pinouts of COM-to-motherboard connectors. May be, You're just only using wrong one...(if that motherboard came without COM connectors, it is quite usuall thing

).
It can be resoldered,though... Just only about one month ago I had to resolder pins on COM1 connector for my Soyo 6BB motherboard...

**Garak** · September 2nd, 2002, 01:58 PM

I've tried 3 different sets of ports, including the ones that came with the board (it was the reason I got the board in the first place) I am just wondering what would cause it to die now.
Any ideas?

thnks

**Ruslan** · September 3rd, 2002, 07:56 AM

Updating the BIOS with wrong version (version, written for another I/O chip) can cause COM ports (as well as LPT and floppy controller) stop responding...
Is it worked well when You bought it?
Both of the COM ports are not working?
I've seen also some motherboards, what required exact settings for COM ports (i.e. 3F8,2F8 instead of "AUTO")...

Take a look at COM interface chips, may be they are fried and cracked (IC like GD75232 or similar). These chips can easily enough replaced with similar ones...

Output COM controller buffer can be built-in I/O chip - then not so much You can do in that case - You will need exactly same chip...

I will try to take a look on the picture of that motherboard more closely, though...

But anyways, You can get almost for free (or even for free

) an old ISA COM - LPT controller from otdated 286-486 PC...

**Garak** · September 3rd, 2002, 10:15 AM

a little red fuse thing on the board looks burnt out, like a clear transistor / resistor type thing (don't know what they are called..)

Possibly this is the problem?? If this is replaced do you think the com ports will work again?

G.

**Ruslan** · September 3rd, 2002, 07:26 PM

Resistor on PCB is usually marked as Rxx, fuse - Fxx, transistor - Txx or Qxx, diode - Dxx or Qxx,filter coil - Lxx...

Try to replace it...it should fix the problem, I think - personally I did it many times with almost 100% result...

**Garak** · September 3rd, 2002, 07:52 PM

Originally posted by Ruslan
Resistor on PCB is usually marked as Rxx, fuse - Fxx, transistor - Txx or Qxx, diode - Dxx or Qxx,filter coil - Lxx...

Try to replace it...it should fix the problem, I think - personally I did it many times with almost 100% result...

It is marked D3, small, clear plastic shell with a red led type thing in it..

G.

**Ruslan** · September 3rd, 2002, 08:00 PM

Just checked the picture of that motherboard:

This motherboard has mentioned GD75232 chips as output buffer IC for COM ports. These chips are usually quite reliable ones and are not dying simultaneously... So, most likely it is just only blown fuse...