IBM PC 5150 Not Booting on DOS 3.2

[Perjos]

Hi guys,

My 5150 boots on DOS 2.02 and works very well, but when trying to boot on DOS 3.2 it shows the following message:

PARITY CHECK

and nothing more happens!

Someone already had this problem?

Thanks

 

[kgober]

This isn't one of those 64KB 5150's, is it? I read that IBM recommended having 128KB for DOS 3.0, I doubt 3.2 would have required any less.

 

[SpidersWeb]

Trying to boot DOS 3 on my 64KB IBM failed but I didn't get Parity Error. I think it was just a "not enough memory" type of message (can't remember 100%)
Can you run programs on DOS 2 without fault? Old version of checkit to do a memory test?

 

[Stone]

CheckIt won't run on 64K. CheckIt 3 won't even run on 256K!

 

[modem7]

Welcome to these forums.

My 5150 boots on DOS 2.02 and works very well, but when trying to boot on DOS 3.2 it shows the following message:
PARITY CHECK
and nothing more happens!

Per [here], what the IBM 5150's BIOS displays is either "PARITY CHECK 1" or "PARITY CHECK 2".
It does not display "PARITY CHECK" without a corresponding number.

What are you seeing? "PARITY CHECK" or "PARITY CHECK 1" or "PARITY CHECK 2" ?

If "PARITY CHECK"

A few months ago, the cause of "PARITY CHECK" on an IBM 5170 was a virus.

If "PARITY CHECK 1" or "PARITY CHECK 2"

It could be that when DOS 2.02 loads, the address/es of bad parity is not read, but is when DOS 3.2 loads.

If you have not done so, it is worth re-seating all RAM chips in their sockets, in case of a poor connection. I suggest that you use anti-static procedures.

If that does not remove the symptom, then as already posted, you should test the RAM.

Also, based on the IBM 5150 information at minuszerodegrees.net, tell us:
* Which of the two motherboard types you have;
* The revision of motherboard BIOS;
* How many banks of motherboard RAM are populated;
* What conventional RAM you have on expansion cards.

With that, we can confirm that you have the correct RAM-related switch settings the motherboard. Normally if those switches are incorrectly set, a false 201 error is shown, but there are some incorrect settings that can result in "PARITY CHECK 1" / "PARITY CHECK 2".

 

[modem7]

I think it was just a "not enough memory" type of message (can't remember 100%)

What IBM DOS 3.3 displays is shown at [here].

 

[Perjos]

Hi,

No it is a 256kb version!

 

[Perjos]

Hi,

It is only PARITY CHECK and a blink cursor!
My motherboard is the last model!
BIOS revision last version!
All memory banks are populated
Total memory is 640k

Without booting on DOS 3.2 all 640bkb are checked and it ok.

 

[modem7]

Without booting on DOS 3.2 all 640bkb are checked and it ok.

Note that the RAM test in the power-on self test (POST) is crude, a confidence thing only. Crude so that the test does not take too long. For proper testing of RAM, IBM have a RAM test on their diagnostics floppy.

Also, the POST disables parity checking during its check of RAM.

My motherboard is the last model!
BIOS revision last version!

So you have the 10/27/82 revision of BIOS (i.e. chip in U33 socket has "1501476" printed on it).

Per [here], when I search that BIOS, the only occurrences of "PARITY CHECK" that I find are "PARITY CHECK 1" and "PARITY CHECK 2".

So, with your 5150 having that BIOS, and you seeing only "PARITY CHECK", I think of:

* A virus, or other malicious code, that displays "PARITY CHECK"; or
* The parity check message is only momentarily appearing and there is not enough time to make out the 1 or 2.


On my late IBM 5150 (containing a 64KB-256KB motherboard with 10/27/82 BIOS), if I remove RAM chip U53 (parity bit in bank 1 per [here]), then at power-on, the machine displays:

then freezes.