KLund1
Veteran Member
I have a IBM 5160 256-640 KB motherboard. (the brown one)
It is showing 1/4 the installed ram.
I have just the board with 1 row in bank 0 of tested good 256KB 150ns ram and just a video card. nothing else
The ram counts up to only 64Kb !!
The MB SW1 3, 4 are set to ON so only bank 0 is enabled. The other banks are empty.
I pulled the chips, retested them in a ram tester, cleaned the sockets with a anti-static brush, and ISO. The some canned air to dry the sockets out.
Reinstalled ram, powered it up and get the same results !
I deOxoit'ed the SW1, No change.
I tested SW 3 & 4 with procedure here: all good
But If I put 64Kb 200ns chips in bank 0, The ram count shows 64Kb. ( these chips also tested in separate ram tester, all good)
Results of more testing: (all chips for all banks tested good in separate ram tester)
Bank 0 - 256KB chips=64
Bank 0 - 64KB chips =64
Bank0 -256kb chips +
Bank1 -256kb chips = 128
Bank0 -256kb chips +
Bank1 -64kb chips = 128
Bank 0 - 64KB chips +
Bank1 -64kb chips = 128
This pattern continues. The most I can get with all banks populated properly is 256KB
as shown here near the top:
I have added a little pressure to the switches when powering up to see if that changes anything. but it does not.
I have reseated the other 4 socketed chips about the board.
Not sure if this maters, but all 256 chips are 150ns, the 64's are mixed 150ns & 200ns
I am thinking that a support chip has half failed. But I have no idea which one that might be.
Some help or suggestions please.
Thanks
It is showing 1/4 the installed ram.
I have just the board with 1 row in bank 0 of tested good 256KB 150ns ram and just a video card. nothing else
The ram counts up to only 64Kb !!
The MB SW1 3, 4 are set to ON so only bank 0 is enabled. The other banks are empty.
I pulled the chips, retested them in a ram tester, cleaned the sockets with a anti-static brush, and ISO. The some canned air to dry the sockets out.
Reinstalled ram, powered it up and get the same results !
I deOxoit'ed the SW1, No change.
I tested SW 3 & 4 with procedure here: all good
But If I put 64Kb 200ns chips in bank 0, The ram count shows 64Kb. ( these chips also tested in separate ram tester, all good)
Results of more testing: (all chips for all banks tested good in separate ram tester)
Bank 0 - 256KB chips=64
Bank 0 - 64KB chips =64
Bank0 -256kb chips +
Bank1 -256kb chips = 128
Bank0 -256kb chips +
Bank1 -64kb chips = 128
Bank 0 - 64KB chips +
Bank1 -64kb chips = 128
This pattern continues. The most I can get with all banks populated properly is 256KB
as shown here near the top:
I have added a little pressure to the switches when powering up to see if that changes anything. but it does not.
I have reseated the other 4 socketed chips about the board.
Not sure if this maters, but all 256 chips are 150ns, the 64's are mixed 150ns & 200ns
I am thinking that a support chip has half failed. But I have no idea which one that might be.
Some help or suggestions please.
Thanks