PB520R Motherboard Connectors

J#	Description
J1	KEYBD
J2	MOUSE
J3	VIDEO
J4	COM2
J5	PARALLEL
J6	COM1
J8	Not used
J9	VESA
J10	RISER SLOT
J11	Auxilliary 3.3V Power
J12	Primary Power
J13	Not used
JUMPER	FUNCTION
J21	JMOD
JUMPER	FUNCTION
J22	PCI IDE
JUMPER	FUNCTION
J23	IDE
JUMPER	FUNCTION
J24	FLOPPY
J25	SIMM BANK B
J26	SIMM BANK B
J27	SIMM BANK A (EMPTY)
J28	SIMM BANK A (EMPTY)
J29	Auxiliary 12V Fan Power
J30	Auxiliary 10V Fan Power
J31	RESET
J32	PWR LED
J33	HD LED
J34	TURBO LED
J35	KEYLOCK
J36	EXT STANDBY
J37 SPKR	Ext. Speaker connector

U2B1: CPU Socket

Pentium 60 MHz
Uses the 273-Pin Type 4 Zero Insertion Force (ZIF) CPU.
Not Keyboard Switchable to non turbo
Disable cache to slow system
Not upgradable to 75MHz/90MHz/100MHz Pentium CPU

U4A1-U6B2: Level 2 Cache
AS7C256 Cache Memory 32kx8-15ns
Also see: Cache Upgrade Information

U2H1-U4J2: Main RAM
TMS444000 Main memory 4Mx1-70
Also see: RAM Memory Upgrade Information

U10A1/U11A1: Video Memory Upgrade Sockets

Also see: Video RAM Upgrade Information

U10B1/U11B1: Built-In Video Memory
MT4C16257 Video Memory 256kx16

U11D1: Cirrus Video Controller
CD-GL5434 Cirrus Logic Video Controller

SIMM Sockets
Note

Earlier version of the PB520R motherboards have only two SIMM sockets. This motherboard uses sockets J25 and J26 (Bank B) as the primary bank. Motherboards with two SIMM sockets can only be upgraded to 72MB.
All new releases of the PB520R motherboards have four SIMM sockets, accommodating up to 136MB of total RAM upgrade. In this case, J27 and J28 (Bank A) will become the primary bank.

Uses 1/2/4/8/16/32 MB 72-pin SIMMs, 70ns

Also see: RAM Memory Upgrade Information

J37

J1: Keyboard Port
6-Pin Mini-DIN Keyboard Connector

J2: Mouse Port
6-Pin Mini-DIN Mouse Connector

J3: Video Port
15-Pin HD Sub-D Video Connector

J5: Parallel Port
25-Pin D Shell Parallel Port Connector

J6: Serial Port
9-Pin D-Shell Serial Port Connector

J9: VESA
26-Pin (2 x 13 Header) Video Feature Connector

J10: Riser
Riser Card Connector

J11: 3.3V PCI Power Connector
PCI Bus Power Connector

J12: Main Power Connector

J21: Modem
20-Pin (2 x 10 Header) DB Modem Connector

J22: PCI IDE Connector
40-Pin (2 x 20 Header) PCI Hard Drive Connector

J23: ISA IDE Connector
40-Pin (2 x 20 Header) ISA Hard Drive Connector

J24: Floppy Connector
34-Pin (2 x 17 Header) Floppy Drive Connector

J29: Auxiliary 12-Volt Fan Power Connector
Pin 1 Ground
Pin 2 +12 Volts
Pin 3 Ground

J30: Auxiliary 10-Volt Fan Power Connector
Pin 1 Ground
Pin 2 +10 Volts
Pin 3 Ground