Editing IBM PS2 Model 30 Schematics (section)

== Contents ==
{| class="wikitable styled-table"
! Sheet !! Title !! Rev !! Date
|-
| 1 || Buss & I/O || 3 || 6/9/91
|-
| 2 || CPU || 4 || 6/13/91
|-
| 3 || Memory || 3 || 6/9/91
|-
| 4 || Printer I/O || 3 || 6/9/91
|-
| 5 || Serial I/O || 3 || 6/9/91
|-
| 6 || Disk I/F & RTC || 3 || 6/9/91
|-
| 7 || Video Interface || 4 || 6/13/91
|-
| 8 || DMA Interface || 3 || 6/9/91
|}

The drawings carry designators and values for the parts on each circuit. Sheet 6, for example, shows the 8272A diskette controller (U18) and gate array 72X8206 (U14) driving the floppy connector J12, the MC4044 (U39) in the data separator with its filter (R87 and R88 2 kΩ, R90 1.3 kΩ, C79 39 nF, C28 27 nF, C67 68 pF), and the real-time clock circuit: Y4 32.768 kHz with C83 4.7 pF, C84 10 pF, R96 22 MΩ and R97 300 kΩ, the VBAT feed through CR5 (BAV70) with C77 10 µF, and Q4 (MMBT3904) with R70 47 kΩ. On that sheet the clock chip is labelled "U18 8272A A", the same designator and part number as the diskette controller; treat that label with care.