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View Full Version : Samsung S330 XT clone: Keyboard Error, mangled motherboard



DamienC
March 4th, 2014, 10:55 AM
I have an old Samsung S330 XT clone PC that used to belong to my uncle. He gave it to me around 2000 or 2001, and it's basically sat in a closet at my parents' house since then.

I'm trying to get the system back up and running. It has an Everex EGA card, a floppy controller/IO card, a Western Digital MFM/RLL controller card, and a 5.25" 360k floppy drive. The original 20mb Seagate HD died, so I bought a 40mb replacement drive that I can't really test yet.

The problem is that I get a "Keyboard Error Or No Keyboard Present" message from the BIOS, and can't get past it. I remember back in the late 90s the system got this error when my uncle had it set up, but we'd always just "Hit F1 to continue" and the system would chug along happily, working keyboard and all. The keyboard is an 83 key IBM Model F BTW. Yesterday I pulled the whole thing apart to see if there was perhaps some physical damage.

The motherboard is a total wreck; I'm kind of amazed it boots at all. The power LED and PC speaker are crudely soldered to the pins on the board. The CMOS battery was dead and leaking, but I expected that. But that wasn't the worst of it.

It looks like at one point the computer had onboard I/O, but someone PURPOSELY clipped the pins off of a bunch of the chips! I think they just used some sidecutters and just went nuts on the board. I didn't know what all of the "clipped" chips were, but they definitely mangled the HD controller chip and even managed to yank off several legs of a QFP on the board. My gut tells me that my uncle used a shady repair shop, and that they purposely broke things to sell him a new I/O controller board. I know for a fact they installed pirated software all the time; he would take the machine to the shop and come home with stuff like AutoCAD, Deluxe Paint and Wordperfect (not to mention tons of games).

Anyone know where I can start looking on the board to fix the keyboard problem? I read +5VDC on more than one of the pins for the keyboard connector, which I'm pretty sure is just plain wrong (I think only pin 5 should have +5VDC). I have a Zeos keyboard that has an AT/XT selector switch; when I set it to XT mode and try using that, all three keyboard LEDs flash about 5-10 times during BIOS startup before the PC gets the error message.

I'll try to post some pics of the board sometime tonight.

EDIT: Here are some pics. (http://imgur.com/a/AbNot) (Imgur album link)

modem7
March 5th, 2014, 12:48 AM
How the keyboard initialisation works in the IBM XT (IBM 5160) is shown [here (http://www.minuszerodegrees.net/5160/keyboard/5160_keyboard_startup.jpg)].
Your Samsung clone may be the same, but it may differ.


I have a Zeos keyboard that has an AT/XT selector switch; when I set it to XT mode and try using that, all three keyboard LEDs flash about 5-10 times during BIOS startup before the PC gets the error message.
A lot of keyboards flash their LEDs as part of their self test, and as I discovered, often, the supply of +5 volts alone is enough to trigger the keyboard's self test.


I read +5VDC on more than one of the pins for the keyboard connector, which I'm pretty sure is just plain wrong (I think only pin 5 should have +5VDC).
Lines like the CLOCK line normally sit high.


The problem is that I get a "Keyboard Error Or No Keyboard Present" message from the BIOS, and can't get past it. I remember back in the late 90s the system got this error when my uncle had it set up, but we'd always just "Hit F1 to continue" and the system would chug along happily, working keyboard and all. The keyboard is an 83 key IBM Model F BTW.
Is that Model F the keyboard that was used in the late 90s ?

I ask because forum members have run across keyboard-to-computer compatiblity issues. Recently there was someone who, from memory, tried four different models of XT-class keyboards before finding one that worked with their computer.

DamienC
March 5th, 2014, 04:02 AM
Is that Model F the keyboard that was used in the late 90s ?

I ask because forum members have run across keyboard-to-computer compatiblity issues. Recently there was someone who, from memory, tried four different models of XT-class keyboards before finding one that worked with their computer.

I'm pretty sure the keyboard is of a late 80s vintage; I definitely remember using it between 1990 and 2000 when my uncle had it. It looks identical to this one (http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/11066/subcatid/0/id/171727). I did see some pics of late model F keyboards that look a little nicer and have Caps/Num/Scroll lock LEDs.

I'll have to see if I can get another keyboard. Unfortunately that will have to wait, as I'm not willing to pay internet prices for anything at the moment and flea market season is a couple months away.

I was wondering if one of those damaged chips on the motherboard was a keyboard controller chip or something that I could maybe resolder.

modem7
March 6th, 2014, 12:23 AM
It looks like at one point the computer had onboard I/O, but someone PURPOSELY clipped the pins off of a bunch of the chips!

I was wondering if one of those damaged chips on the motherboard was a keyboard controller chip or something that I could maybe resolder.
Your photos of 'damaged' chips certainly indicates to me an intent to purposely disable the chips.

If someone purposely disabled the keyboard circuitry (whether that be a dedicated controller chip or discrete chips), the question becomes, what were their plans to provide alternate keyboard functionality?

I mean, surely the "shady repair shop" did not return the computer to your uncle, saying, "The keyboard no longer works. Yes, we are aware the keyboard was working when you handed the computer to us."

modem7
March 7th, 2014, 01:48 PM
I'll have to see if I can get another keyboard. Unfortunately that will have to wait, as I'm not willing to pay internet prices for anything at the moment and flea market season is a couple months away.
Assuming that you have AT-class keyboards, another option is the use of an AT2XTKB Keyboard Converter, pictured [here (http://www.minuszerodegrees.net/at2xtkb/AT2XTKB.htm)].
Maybe a forum member near to you (wherever that is) will sell you one. It should be cheaper than a keyboard.