J-MARK COMPUTER CORPORATION J-646B Processor Pentium Processor Speed 75/90/100/120/133/150/166MHz Chip Set SIS Video Chip Set None Maximum Onboard 128MB (EDO supported) Memory Maximum Video Memory None Cache 256/512/1024KB BIOS Award Dimensions 330mm x 218mm I/O Options 32-bit PCI slots (3), floppy drive interface, IDE interfaces (2), parallel port, PS/2 mouse interface, serial ports (2) NPU Options None [Image] CONNECTIONS Purpose Location Purpose Location Speaker CN1 Serial port 2 J8 Reset switch CN2 Serial port 1 J9 Turbo LED CN3 Parallel port J10 Power LED & keylock CN4 Floppy drive J11 interface Turbo switch CN5 IDE interface 1 J12 IDE interface LED CN6 IDE interface 2 J13 BK LED CN7 External battery J15 PS/2 mouse interface J2 32-bit PCI slots PC1 – PC3 VGA feature connector J7 USER CONFIGURABLE SETTINGS Function Label Position » Factory configured - do not J6 Unidentified alter » Factory configured - do not JP4 Unidentified alter » Factory configured - do not JP5 Unidentified alter » Factory configured - do not JP6 Unidentified alter » Factory configured - do not JP7 Unidentified alter » Factory configured - do not JP9 Open alter » Factory configured - do not JP15 Unidentified alter » CPU write select write back JP16 Pins 1 & 2 closed CPU write select write through JP16 Pins 2 & 3 closed » CPU pipeline enabled JP17 Pins 2 & 3 closed CPU pipeline disabled JP17 Pins 1 & 2 closed » Suspend mode disabled JP20 Open Suspend mode enabled JP20 Closed » Break switch for suspend mode JP24 Pins 2 & 3 closed 8042 RC enabled JP24 Pins 1 & 2 closed » Monitor type select monochrome JP25 Open Monitor type select color JP25 Closed » Factory configured - do not JP26 Unidentified alter » Factory configured - do not JP27 Unidentified alter » Factory configured - do not JP28 Unidentified alter » Factory configured - do not JP29 Unidentified alter » Factory configured - do not JP30 Unidentified alter » Factory configured - do not JP31 Unidentified alter » Factory configured - do not JP32 Unidentified alter » Factory configured - do not JP33 Unidentified alter » Factory configured - do not JP34 Unidentified alter » Factory configured - do not JP35 Unidentified alter » Factory configured - do not JP36 Unidentified alter » Factory configured - do not JP37 Unidentified alter USER CONFIGURABLE SETTINGS (CON’T) Function Label Position » CMOS memory normal operation JP38 Pins 1 & 2 closed CMOS memory clear JP38 Pins 2 & 3 closed » PCICLK speed select 1/2 CPU JP39 Closed CLK PCICLK speed select = 32MHz JP39 Open » PS/2 IRQ12 enabled JP41 Closed PS/2 IRQ12 disabled JP41 Open » Factory configured - do not JP42 Unidentified alter DRAM CONFIGURATION Size Bank 0 Bank 1 Bank 2 Bank 3 4MB (1) 1M x 36 None None None 8MB (1) 2M x 36 None None None 8MB (1) 1M x 36 (1) 1M x 36 None None 16MB (1) 4M x 36 None None None 16MB (1) 2M x 36 (1) 2M x 36 None None 16MB (1) 1M x 36 (1) 1M x 36 (1) 1M x 36 (1) 1M x 36 24MB (1) 1M x 36 (1) 1M x 36 (1) 2M x 36 (1) 2M x 36 32MB (1) 8M x 36 None None None 32MB (1) 4M x 36 (1) 4M x 36 None None 32MB (1) 2M x 36 (1) 2M x 36 (1) 2M x 36 (1) 2M x 36 40MB (1) 4M x 36 (1) 4M x 36 (1) 1M x 36 (1) 1M x 36 48MB (1) 4M x 36 (1) 4M x 36 (1) 2M x 36 (1) 2M x 36 64MB (1) 4M x 36 (1) 4M x 36 (1) 4M x 36 (1) 4M x 36 72MB (1) 8M x 36 (1) 8M x 36 (1) 1M x 36 (1) 1M x 36 80MB (1) 8M x 36 (1) 8M x 36 (1) 2M x 36 (1) 2M x 36 96MB (1) 8M x 36 (1) 8M x 36 (1) 4M x 36 (1) 4M x 36 128MB (1) 8M x 36 (1) 8M x 36 (1) 8M x 36 (1) 8M x 36 Note: Board accepts EDO memory. Board also accepts x 32 SIMMs. DRAM VOLTAGE CONFIGURATION Voltage JP1 » Mixed mode Pins 3 & 5, 4 & 6 closed 3.3v Pins 1 & 3, 2 & 4 closed CACHE CONFIGURATION Size Bank 0 Bank 1 TAG 256KB (A) None (8) 32K x 8 (1) 8K x 8 256KB (B) (2) 32K x 32 None Unidentified 512KB (A) None (8) 64K x 8 (1) 16K x 8 (Windbond) 512KB (B) None (8) 64K x 8 (1) 16K/32K x 8 (Aster) 1MB None (8) 128K x 8 (1) 32K x 8 Note: The location of bank 1 & TAG are unidentified. CACHE JUMPER CONFIGURATION Size JP3 JP11 JP42 256KB (A) Pins 1 & 2 Pins 1 & 2 Open closed closed 256KB (B) Pins 1 & 2 Pins 1 & 2 Open closed closed 512KB (A) Pins 2 & 3 Open Closed closed 512KB (B) Pins 2 & 3 Pins 1 & 2 Open closed closed 1MB Pins 2 & 3 Pins 2 & 3 Open closed closed CPU SPEED SELECTION CPU Clock Multiplier JP12 JP13 JP18 JP19 speed speed 75MHz 50MHz 1.5x Closed Closed Open Open 90MHz 60MHz 1.5x Closed Open Open Open 100MHz 66MHz 1.5x Open Closed Open Open 120MHz 60MHz 2x Closed Open Open Closed 133MHz 66MHz 2x Open Closed Open Closed 150MHz 60MHz 2.5x Closed Open Closed Closed 166MHz 66MHz 2.5x Open Closed Closed Closed CPU VOLTAGE SELECTION Voltage JP21 JP22 JP23 3.3v Closed Open Open » 3.45v Open Closed Open 3.6v Open Open Closed VGA SELECTION Setting JP2 JP8 JP10 » Onboard VGA Pins 1 & 2 Closed Closed closed External VGA Pins 2 & 3 Open Open card closed