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IBM 5150 Error Code: 106E 201

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strollin

Experienced Member
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Apr 16, 2008
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I'm getting an error code of 106E 201 when I try to boot my 5150. According to the Hardware Maintenance and Service Manual that frozenfire75i posted on his website, the first digit of 1 is supposed to indicate that this memory error is occurring on a memory option board. This is a 16-64K mobo and I have removed 2 memory cards as well as all of the socketed chips so I only have the 16k of soldered memory in place. I have the mobo switches set to match. Can anybody provide any insight as to why I am getting this error code? Just to make things interesting, sometimes I get an error code of 1055 201.
 
How many extension cards do you got in the machine, what are they and what slot are they in (as of slot no.5 being the closest to the PSU)?

Try pulling out all the adapters, except the display adaptsr, Turn the computer on. If no errors, insert one of the cads and turn the computer on again. Repeat this untill all the cadrs are inserted. When the error appears, the latest inserted card is the problem.
 
Thanks for the reply Per, as I said in my original post, I have already removed the 2 memory cards as well as all of the socketed memory on the mobo. I only have the 16k of memory that's soldered in place. The error code is pointing to memory that's not installed.

I only have the floppy controller and video cards in the machine right now. If I remove the controller card, I get the memory error code plus a 601 error.
 
Double-check your dip-switch settings. Make sure that they reflect 16K RAM on board, and whatever options you have installed, such as the monitor type, and whether or not you've got a co-processor.

--Jack
 
From the following info below (originally posted by Modem7 here), it doesn't appear that your memory error code 106E fits in with the standard usually associated with a faulty chip on a 16-64kB motherboard :confused:

16/64K board
------------
00xx to 03xx = Bank 0 (the XX indicates which chip [or chips] have failed)
04xx to 07xx = Bank 1 (the XX indicates which chip [or chips] have failed)
08xx to 0Bxx = Bank 2 (the XX indicates which chip [or chips] have failed)
0Cxx to 0Fxx = Bank 3 (the XX indicates which chip [or chips] have failed)

64/256K board
------------
00xx to 0Fxx = Bank 0 (the XX indicates which chip [or chips] have failed)
10xx to 1Fxx = Bank 1 (the XX indicates which chip [or chips] have failed)
20xx to 2Fxx = Bank 2 (the XX indicates which chip [or chips] have failed)
30xx to 3Fxx = Bank 3 (the XX indicates which chip [or chips] have failed)


XX is 00 indicates the parity chip
XX is 01 indicates the bit 0 chip
XX is 02 indicates the bit 1 chip
XX is 04 indicates the bit 2 chip
XX is 08 indicates the bit 3 chip
XX is 10 indicates the bit 4 chip
XX is 20 indicates the bit 5 chip
XX is 40 indicates the bit 6 chip
XX is 80 indicates the bit 7 chip

XX is something else indicates multiple chip failure, eg. 24 would indicate bit 5 and bit 2 failure.
Click to expand...
 
Yzzerdd - I've checked and rechecked the switch settings. This may be the issue though, I'm beginning to suspect some of the switches have dirty contacts or something so that they aren't "On" when they are switched to the "On" position. Guess it's time to breal out the ohmmeter and check.

Dongfeng - Yes, as I said in my original post, the error code points to memory that isn't in use.
 
What I would do is change the dip switch settings to the lowest amount of RAM (16K) possible. If you still get an error, you're screwed because the first row "Bank 0" of RAM is not socketed. At this point the computer is ignoring banks 1, 2, and 3 RAM (2nd- 4th rows)

Change the switches to use 32K, if you're error free, switch to 48K. If you're error free for the first 48K, try all 64K.

If you get errors for the 48K row (bank 3), swap the back row RAM with the 3rd row RAM, until you have banks 0,1,2 OK.

Getting the full 64K will require finding a working RAM chip or two from someplace else, and swap out the chips until you have them all working. YOu say you have some extra RAM boards, be careful that they have the same RAM chip markings. Get an opinion if you're not sure.

At least you'll have 48K with no errors using the swap method, enough to boot DOS 2.
 
I had a similar problem several years ago with a 5150 MB, however it was a type "B" (64-256k), not the 16-64k board you have.

Mine has the error 1051 201. This should indicate an error in bank 1 on the 64-256k board. I ended up pulling all the socketed memory chips except for bank 0.

With chips only in bank 0, and the switches set to reflect 64k I still got the same error. Didn't make any sense.

Here is a long thread I posted about it two years ago (Oct. 2006):

http://www.vintage-computer.com/vcforum/showthread.php?t=4573

One of the senior members here (modem7) said it might be a memory addressing problem and there was some possibility it might be chips U47, U65 and U49.

Since it was a spare board, I never did get to unsoldering and replacing some of the support chips for the memory, although I have the information saved so in the future I can attempt the repair.

A type "A" board would be worth more effort trying to repair than my more common "B" board. If mine had been a 16-64k board like yours, I definitely would have made an attempt to fix it.
 
Last edited:
According to the HM&S manual a 1 in the first digit means the error is NOT within the first 64k on the mobo but is on one of the first 64k expansion cards.

I have removed all memory except for the 16k in bank 0 that's soldered. If I thought the error was in that first 16k, I would have no trouble unsoldering those chips and replacing with socketed chips.

This machine was working last week but had a different memory error. I was able to get it to boot without error to 500k of memory (out of a total of 640k). This week I can't get it to boot with only 16k.

Some testing that modem7 did (in the thread that xtguy linked to) indicated that the BIOS still attempted to test memory beyond what the mobo switches were set to. That doesn't make sense to me, otherwise what's the point of the switches?

I'm thinking that even though I am setting the switches to indicate 16k RAM installed, for some reason the switches are being ignored OR the switches are defective/dirty internal contacts.
 
Problem of a third revision BIOS in a 16-64K board

Problem of a third revision BIOS in a 16-64K board

This sounds like something I've seen before but never fully investigated.

A 16-64K board behaves as expected when it is fitted with the second revision BIOS (10/19/81 U33=5700671).
You can remove banks of RAM, setting switches per documentation, and things work as expected.
If a chip fails, you get the expected error code.

But when the third revision BIOS (10/27/82 U33=1501476) is fitted to a 16-64K board, things change.
First, I have never been able to get the motherboard memory working unless the following is true:
1. All four banks populated, and
2. Switches 3 and 4 of SW1 set to OFF.
3. And with no RAM on an expansion card, switches 1 to 5 of SW2 are set to ON.

If you deviate from points 1 and 2 above, depending on the deviation, you then start to see "10xx 201" errors (usually followed by "PARITY CHECK 1").
Don't ask me why this is. It is certainly not in the documentation that was supplied in the BIOS upgrade kit that IBM supplied (I have a kit).

So fully populate the motherboard banks and set switches 3 and 4 of SW1 to OFF.
You should then see an accurate 201 type error per the following:

16/64K board
------------
00xx to 03xx = Bank 0 (the XX indicates which chip [or chips] have failed)
04xx to 07xx = Bank 1 (the XX indicates which chip [or chips] have failed)
08xx to 0Bxx = Bank 2 (the XX indicates which chip [or chips] have failed)
0Cxx to 0Fxx = Bank 3 (the XX indicates which chip [or chips] have failed)

XX is 00 indicates the parity chip
XX is 01 indicates the bit 0 chip
XX is 02 indicates the bit 1 chip
XX is 04 indicates the bit 2 chip
XX is 08 indicates the bit 3 chip
XX is 10 indicates the bit 4 chip
XX is 20 indicates the bit 5 chip
XX is 40 indicates the bit 6 chip
XX is 80 indicates the bit 7 chip

XX is something else indicates multiple chip failure, eg. 24 would indicate bit 5 and bit 2 failure.
 
modem7 said:
This sounds like something I've seen before but never fully investigated.

A 16-64K board behaves as expected when it is fitted with the second revision BIOS (10/19/81 U33=5700671).
You can remove banks of RAM, setting switches per documentation, and things work as expected.
If a chip fails, you get the expected error code.

But when the third revision BIOS (10/27/82 U33=1501476) is fitted to a 16-64K board, things change.
First, I have never been able to get the motherboard memory working unless the following is true:
1. All four banks populated, and
2. Switches 3 and 4 of SW1 set to OFF.
3. And with no RAM on an expansion card, switches 1 to 5 of SW2 are set to ON.

If you deviate from points 1 and 2 above, depending on the deviation, you then start to see "10xx 201" errors (usually followed by "PARITY CHECK 1").
Don't ask me why this is. It is certainly not in the documentation that was supplied in the BIOS upgrade kit that IBM supplied (I have a kit).

So fully populate the motherboard banks and set switches 3 and 4 of SW1 to OFF.
You should then see an accurate 201 type error per the following:

16/64K board
------------
00xx to 03xx = Bank 0 (the XX indicates which chip [or chips] have failed)
04xx to 07xx = Bank 1 (the XX indicates which chip [or chips] have failed)
08xx to 0Bxx = Bank 2 (the XX indicates which chip [or chips] have failed)
0Cxx to 0Fxx = Bank 3 (the XX indicates which chip [or chips] have failed)

XX is 00 indicates the parity chip
XX is 01 indicates the bit 0 chip
XX is 02 indicates the bit 1 chip
XX is 04 indicates the bit 2 chip
XX is 08 indicates the bit 3 chip
XX is 10 indicates the bit 4 chip
XX is 20 indicates the bit 5 chip
XX is 40 indicates the bit 6 chip
XX is 80 indicates the bit 7 chip

XX is something else indicates multiple chip failure, eg. 24 would indicate bit 5 and bit 2 failure.
Click to expand...

I have the third revision BIOS. I repopulated all banks on the mobo and set the switches as you stated, the 106E 201 error went away and I was able to boot to DOS. I put the 512k memory card back in and now I have a different error code (didn't write it down) but the machine boots to DOS and reports I have something like 734k available!? I'm done for tonight.

The difference seems to be that you stated that switch 5 on SW2 be set to ON. In my GTO it states that switches 5,6,7 & 8 on SW2 must always be OFF.

Also my GTO states that switch 2 on SW1 is not used and must be set to ON. Other documentation I've seen say that switch 2 of SW1 indicates the presence of a co-processor and must be set to off if no co-processor is installed. The machine doesn't have a co-processor installed and I have the switch set to OFF.

Thanks all, I'm not totally out of the tunnel yet but I can see light at the other end.
 
strollin said:
The difference seems to be that you stated that switch 5 on SW2 be set to ON. In my GTO it states that switches 5,6,7 & 8 on SW2 must always be OFF.
Click to expand...
As a point of interest, the 5150 motherboard schematics for both the 16-64K and 64-256K boards shows that switches 6/7/8 on SW2 are not connected. Therefore, the manuals should list their setting as "don't care".

Switch 5 is a different story - it is connected and read by the BIOS. Your GTO is sure to be an early one because my early Tech Ref indicates the same: switches 5 to 8 on SW2 always off. But those books were written at the time of the first and second BIOS. Those BIOS' only look at switches 1 to 4 of SW2, and by the way, that is why those BIOS can only recognise up to 544K of RAM.
The third BIOS starts to look at switch 5 of SW2 as well (to up the 544K limit to 640K). So when you had SW2-5 off, the third BIOS would have thought that you had either 576K/608K or 640K of RAM, hence generating an error.

strollin said:
I put the 512k memory card back in and now I have a different error code (didn't write it down) but the machine boots to DOS and reports I have something like 734k available!? I'm done for tonight.
Click to expand...
That 512K card will need to be configured so that the RAM on it starts at address 64K (ie. at the end of the 64K on the motherboard). Then you'll have 576K (64K + 512K) contiguous RAM and accordingly you'll need to set SW2 to 1=ON, 2=ON, 3=ON, 4=ON, 5=OFF

strollin said:
Also my GTO states that switch 2 on SW1 is not used and must be set to ON. Other documentation I've seen say that switch 2 of SW1 indicates the presence of a co-processor and must be set to off if no co-processor is installed. The machine doesn't have a co-processor installed and I have the switch set to OFF.
Click to expand...
co-processor present: SW1-2 set to OFF (allows the interrupt from the co-processor through to interrupt logic)
co-processor absent: SW1-2 set to ON
 
IBM 64-256k Memory Card (ISA)

IBM 64-256k Memory Card (ISA)

Anyone have the setting for this card, it has one set of dip switches.

The card reads: 1501989 XM

Thanks!
 
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