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PS/55 5545 and PS/2 P70 Planar Comparison

Introduction
Component Side
Solder Side

Original 5545 photos and information provided by Daehan Lee. Page created by Tomáš Slavotínek.

Introduction

This is a comparison of the PS/55 5545-T planar and the "new" PS/2 8573 P70 planar.

• PS/55 5545-T planar: "SYS CARD J", "IGH 0396BA", FRU P/N 65F0064, P/N 65F0028 (EC C72779 shown)
• PS/2 8573 P70 planar: "SYS CARD DX", "IGH 0322DA", FRU P/N 56F9084, P/N 56F7435 (EC C13312 shown)

Both boards are of Japanese design and were manufactured by Matsushita.

Note: The list of differences below may not be exhaustive. There may be other subtle differences between the two planars. Further, other revisions of these boards may exist.

Component Side

PS/55 5545 Planar

PS/2 P70 Planar

• The 5545 planar uses a 40.0000 MHz oscillator (20 MHz CPU clock).
  All known samples of the "new" P70 planar use a 32.0000 MHz oscillator (16 MHz CPU).

PS/55 5545 Planar

PS/2 P70 Planar

• PAL 16L8 "CS" is populated on the 5545 planar. Only solder pads on the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• 74F373 is populated on the 5545 planar. Only solder pads on the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• The 5545 planar uses I/O GA P/N 65X1380. The P70 uses P/N 33F5838 instead.

PS/55 5545 Planar

PS/2 P70 Planar

• The 5545 planar uses ROM P/N 79F7128. The P70 uses P/N 56F7439 instead.

PS/55 5545 Planar

PS/2 P70 Planar

• 0-ohm resistor R242 is populated on the 5545 planar. Only solder pads on the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• 74ALS74A and 74ALS1005 are populated on the 5545 planar. Only solder pads on the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• The 8042 position is populated on the 5545 planar with a GA P/N 38F7099. Only solder pads on the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• Jumper JP4 is exclusive to the 5545 planar. No solder pads on the P70.
• Jumper JP2 is relocated slightly.
• Electrolytic capacitor C55 is relocated.

PS/55 5545 Planar

PS/2 P70 Planar

• EXT FDD connector, 74FLS07, 74LS14, 74LS06, RN1, RN2, R1, C1, C2, C4-8, C10-15 are exclusive to the P70.
  No solder pads on the 5545 (the layout of this area is completely different).
• Instead, the 5545 planar has only three components in the same area - 1x 74LS14 and 2x 74ALS244.

Solder Side

PS/55 5545 Planar

PS/2 P70 Planar

• 74LS125A is new on the 5545 planar. No solder pads on the P70.
• Resistor R254 and MLCC C232 are new on the 5545 planar. No solder pads on the P70.
• Resistor R255 pads are new on the 5545 planar. No solder pads on the P70.

Note: The xtal has been removed by the author of the photos for replacement.

PS/55 5545 Planar

PS/2 P70 Planar

• 0-ohm resistor R83 is populated on the P70 planar. Only solder pads on the 5545.
• Resistor pads R243,244,247,248,250,251 are exclusive to the 5545 planar. No solder pads on the P70.
• 0-ohm resistors R245,246,249,252 are new on the 5545 planar. No solder pads on the P70.
• MLCC C231 is new on the 5545 planar. No solder pads on the P70.
• Resistor R74 is relocated.
• The component pins missing on the 5545 planar belong to the EXT FDD connector and resistor networks RN1/RN2 exclusive to the P70.

PS/55 5545 Planar

PS/2 P70 Planar

• Resistors R99 and R101 are populated on the P70. Only solder pads on the 5545.
• Resistor R253 is new on the 5545. No solder pads on the P70.