PB520 RAM Memory Upgrade

Caution

Only authorized service personnel should upgrade the system. Anyone who wants to upgrade the system herself/himself should know about the dangers of ESD (Electro-Static Discharge) and the necessary precautions. Unknowingly zapping the components of the computer will void the warranty.

Specifications

SIMM speed must be 70ns or faster.
The simms are 72-pin and can be x32 or x36. The motherboard design does not require parity checking, hence the cheaper x32 simms can be purchased.
Some motherboards may have 2 or 4 SIMM sockets. Therefore, allowing a maximum of either 72 or 136 MB.

Socket Locations
SIMMs are inserted in Bank A or B, sockets J25 - J28. One Bank must be filled when the upgrade is done. Some systems may have a second bank (A) for a maximum of 136MB. When bank A is not present then bank B becomes the first bank.

Upgrade Table

SIMM Bank 0 SIMM Bank 1 Total System Memory

72 pin 4, 8MB X 32 72 pin 4, 8MB X 32

4MB 4MB None None 16MB

4MB 4MB 4MB 4MB 24MB

4MB 4MB 8MB 8MB 32MB

4MB 4MB 16MB 16MB 48MB

4MB 4MB 32MB 32MB 80MB

8MB 8MB None None 24MB

8MB 8MB 4MB 4MB 32MB

8MB 8MB 8MB 8MB 40MB

8MB 8MB 16MB 16MB 56MB

8MB 8MB 32MB 32MB 88MB

16MB 16MB None None 40MB

16MB 16MB 4MB 4MB 48MB

16MB 16MB 8MB 8MB 56MB

16MB 16MB 16MB 16MB 72MB

16MB 16MB 32MB 32MB 104MB

32MB 32MB None None 72MB

32MB 32MB 4MB 4MB 80MB

32MB 32MB 8MB 8MB 86MB

32MB 32MB 16MB 16MB 104MB

32MB 32MB 32MB 32MB 136MB

SIMM Bank 0		SIMM Bank 1		Total System Memory
72 pin 4, 8MB X 32		72 pin 4, 8MB X 32
4MB	4MB	None	None	16MB
4MB	4MB	4MB	4MB	24MB
4MB	4MB	8MB	8MB	32MB
4MB	4MB	16MB	16MB	48MB
4MB	4MB	32MB	32MB	80MB
8MB	8MB	None	None	24MB
8MB	8MB	4MB	4MB	32MB
8MB	8MB	8MB	8MB	40MB
8MB	8MB	16MB	16MB	56MB
8MB	8MB	32MB	32MB	88MB
16MB	16MB	None	None	40MB
16MB	16MB	4MB	4MB	48MB
16MB	16MB	8MB	8MB	56MB
16MB	16MB	16MB	16MB	72MB
16MB	16MB	32MB	32MB	104MB
32MB	32MB	None	None	72MB
32MB	32MB	4MB	4MB	80MB
32MB	32MB	8MB	8MB	86MB
32MB	32MB	16MB	16MB	104MB
32MB	32MB	32MB	32MB	136MB