Old quirky MOBO

By thoopy39 ·
Hi, I have an old AT motherboard that I've been trying to bring back to life for the heck of it. Although it hasn't seen the light of day in awhile it does come on and post but the keyboard isn't recognized and the ps/2 connection doesn't seem to be working either. Also it shows the hard drive and cd as primary slave when the are set to cable select and plugged into the master end of the cable. The usb connections are working and a usb keyboard will work but it won't work if I try to install an OS. I thought it was a corrupt bios so I flashed the bios with an updated version I had found for this board and no difference. Its a Lucky Star 5V3P ver 2.1 Socket 7 with AGP with 128mb ram and AMD K2 300mhz cpu. It has a 5 pin DIN keyboard connection and a header to connect a ps/2 adapter. I have tried other keyboards and I use a ps2 to 5 pin adapter. Tried it on another old mobo and no problems. If anybody has any ideas or solutions, let me know. Just a shot in the dark!

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OLDY but a goody

by mjd420nova In reply to Old quirky MOBO

Those large AT MOBOs suffered from "plate-thru" failures. This is where a connection from one side of the board to the opposite side breaks. This is due to the huge "growing effect" when things get warmed up and then cooled off. Repeated cycles begins the process. Concentrate on the area around the PS2 connector and traces to the decoder chip. The original models were set up for cable select only, noted by the twisted ribbon between the drive connectors.

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Oldy but goody

by thoopy39 In reply to OLDY but a goody

Thanks for the reply I think it could be static shock to the IO chip possibly. I checked for power to each and they are getting 5 volts each like they should. Not sure how to check the data connections. I will probably do some more checking and if nothing seems to work, I'll just hang on for collection.

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by chieumonguoitai In reply to Old quirky MOBO
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PS/2 and Cable Select

by TheChas In reply to Old quirky MOBO

It was very common for keyboard and PS/2 ports to be damaged if the keyboard or mouse was connected or disconnected with power applied.
Another thing to check is if the +5 volt power for the keyboard is present. Might just be an open soldered in fuse on the motherboard.

As to USB keyboard support, if the BIOS does not have an option for USB legacy mode, some older versions of Windows will not support a USB keyboard. Others will not support a USB keyboard until the USB driver is installed. Best option might be to find an old PS/2 ISA or PCI card.

As to cable select, is your IDE cable a cable select type cable? If not, the cable select option does not work. With cable select, the wiring of the cable takes the place of the drive jumpers for setting Master and Slave.


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