• Please review our updated Terms and Rules here

IBM XT Problem Error 101 S

F

frozenfire75i

Banned
Joined
Oct 21, 2007
Messages
599
Location
~I AM NO LONGER A MEMBER OF THIS FORUM~
Greetings all I have three XT’s here that are all giving me the same error code! Error 101 S, The system boots fine starts DOS ECT. Motherboard is a 256-640K one row of ram populated and the rest on the AST card! Systems have 640K ram! MB Switched to 256K! Removing AST card i still get error!

And ideals? The IBM Book tells me to replace the system board but I don’t think I need to do that!

Upon runing a verison 2.05 of the Dia. It tells me Error 102 now?
 
Last edited:
You've got "IBM XT" in the heading and so I will assume you have IBM 5160s.

When I look through the source code for the 5160 BIOS (the 01/10/86 and 11/08/82 versions), I see that a "101" on-screen error is generated if either of the following two motherboard checks fail:
1. 8259 Interrupt Controller check
2. 8253 Timer check.
And according to the code, after the "101" is displayed, the computer is halted.

Your computers are displaying "101 S", not "101", and your computers aren't halting.
That suggests to me three possibilities:

1. All of your three 5160s have a motherboard problem AND the motherboards are not the original IBM ones.

2. All of your three 5160s have a motherboard problem AND the original IBM BIOS ROMs (U18/U19) have been replaced by third party ones. What is printed on the top of U18 and U19 ?

3. Your motherboards are original and have the original IBM BIOS ROMs, but it's not the motherboards generating the error. During power up, cards contain an expansion BIOS (such as EGA/VGA video cards, PC/XT hard disk controllers) can generate their own error messages. Are you using something in common between the three computers as you test them? For example, moving a video card between the three computers.
 
I'd also recommend taking all the cards out and putting in a known good video card. You'll need to reconfigure the DIP switches. Just add the cards back in one at a time until the problem re-occurs.
 
Well those could be the XT-286 models. They didn't have jumper switches.
Mueller says the 101 error is "System-board interrupt failure(Unexpected interupt)"

Looking at the board layout in Mueller Vol 3, pg 113 it shows a "battery connector" and in the specs a CMOS real-time clock. CMOS Ram 64 bytes.

If the battery was dead or missing wouldn't that generate an interrupt ? The fact that all 3 responded the same would tend to suggest a similiar problem. Unless all 3 of the XT/286s were tampered with, which seems unlikely, or they have an incorrect peripheral when tested it would seem to indicate that.

For example did all 3 have a six-pack card or did you add it or any other card yourself ?
What Keyboard and monitor are you using ? Are you using the same HDD on each or are they already installed ? It supported 20M HDD using a WD ST-506/412 controller.

Since it IS a 286 you need a set-up program. That is basic on any 286. According to Mueller any generic one will work. With the added advantage of also supporting a 14.4 FDD. 640K memory was standard on board but it will support up to 16M ram.

Just noticed the 205 error code, which is "base 128k memory error; memory remapped." You could have a faulty on-board memory chip, but unlikely on all 3. There' a diagnostic program called "CheckIt", unless I'm mixing it up with another common diagnostic disk, QAPlus, which will examine each memory chip for failure. I imagine they're now in "public domain".

Lawrence
 
Last edited:
A dead CMOS batter does not generate an interrupt. Actually, a live one can't generate an interrupt either. All communication to the CMOS chip is done by I/O ports.

An unexpected interrupt is an interrupt caused by a device either on a card or on the motherboard that happens when no interrupts are supposed to be occurring. The POST routine in the BIOS will turn off interrupts for a bit to do the system checks. Eventually interrupts will be allowed on after those checks are done. Something managed to cause an interrupt where none should have been enabled.

Do what Modem7 suggested ...

If it really is a 101, then with a bare motheboard and a video card there are only two sources of interrupts on the machine - the keyboard controller and the system timer. There is one interrupt that can not be disabled called the 'Non-Maskable' interrupt, and that can be tripped by a parity error in the memory.


Mike
 
It’s got to be the motherboard I toke everything down to the basic motherboard video card and floppy.. Changed out the floppy card and video cards with known good ones and still the same error! I don’t think it’s the memory I am not getting any memory errors! So I guess the MB are truly bad!! That’s rare!
 
How odd! Did you check the BIOS like modem7 suggested?

Change the DIPs so they only read the first bank of memory. Just in case it is a memory problem, you can rule out 3 of the banks.
 
What kind of keyboard are you using? Are you using the same one on all three systems? Make sure it is an XT style keyboard and not a AT style. There were some keyboards that had a switch somewhere on them(sometimes hidden under a plastic cover) that allowed you to use them with either an XT or an AT system.
 
You must log in or register to reply here.
Back
Top