IBM moel 30-8086 RAM problem

[rafanaty]

IBM model 30-8086 RAM problem,
I got a new IBM model 30-8086.(It is new for me , it came really nasty).
When booting and reading the amount of Ram it reads about 550kb.
I have tried with different paired Ram that I am positive got 620kb
and I am always getting back less than the RAM real amount.
I got error at boot that is RAM memory 200 something.
1-Why is this happening?
2-How to fix it?
Rafanaty

 

[evildragon]

The Model 30 8086 will have 128K of RAM on the mainboard itself. On the 25 it's in a DIP socket, but I believe it's soldered on the model 30.

 

[WBST]

IBM model 30-8086 RAM problem,
I got a new IBM model 30-8086.(It is new for me , it came really nasty).
When booting and reading the amount of Ram it reads about 550kb.
I have tried with different paired Ram that I am positive got 620kb
and I am always getting back less than the RAM real amount.
I got error at boot that is RAM memory 200 something.
1-Why is this happening?
2-How to fix it?
Rafanaty

PS/2s often do ROM shadowing, so Installed Memory minus 128KB often is a result. I've no experience with the Model 30 or 30-286, but I could well imagine this becomes 640KB minus 64KB, below the 1MB line, if a bad RAM block has been disabled. PS/2 BIOSes usually have the ability to "map out" a block containing a bad chip, the size of block varies between system Models. Run Advanced Diagnostics to attempt to check and/or re-enable a "bad block".

 

[evildragon]

PS/2s often do ROM shadowing, so Installed Memory minus 128KB often is a result. I've no experience with the Model 30 or 30-286, but I could well imagine this becomes 640KB minus 64KB, below the 1MB line, if a bad RAM block has been disabled. PS/2 BIOSes usually have the ability to "map out" a block containing a bad chip, the size of block varies between system Models. Run Advanced Diagnostics to attempt to check and/or re-enable a "bad block".

Model 25 and 30 8086's do not ROM shadow.