The Assemblies

The whole 9845 computer was a highly modular system. One of the drawbacks is, that there are almost no repair service information other than how to exchange complete assemblies ("board swapping"). Nevertheless, the 9845 already incorporated a variety of modern concepts like thermal design, air flow channels, expansion slots for both system upgrades and peripheral interfaces, as well as CRT display, mass storage and printer integrated into a nice, robust and serviceable industrial design, which was cutting-edge at the time and exemplary for later workstations and personal computers.

Mainframe Assemblies


9845A Assemblies

9845A Mainframe Assemblies


9845B/C Assemblies

9845 B/C Mainframe Assemblies

Here is an overview of all known assemblies, each with reference to the specific models where they are in use:

Assembly HP Part No. System Description
  09845-60302 9845B/C
Rear Panel
A0 09845-66500 9845B/C
Mother Board, Main Chassis
  09845-66501 9845A
Mother Board, Main Chassis
A2 09845-66502 9845A/B/C
I/O Backplane
A3 09845-66503 9845A/B
Alpha Control (98750A)
A4 09845-66504 9845B
Graphics Interconnect Assembly (no Printer)
A11 09845-66511 9845A
Processor Assembly
A12 09845-66512 9845A
Memory Address Extension
A15 09845-66515 9845B/C
Language Processor - Memory Controller
A16 09845-66516 9845B/C
Peripheral Processor - Memory Controller
A21 09845-66521 9845A
Dual Port Memory Controller
A22 09845-66522 9845A
16 kBytes LPU R/W Memory
A23 09845-66523 9845A
8 kBytes PPU R/W Memory
A26 09845-66526 9845B/C
128 kBytes R/W Memory Expansion
A27 09845-66527 9845B/C
Peripheral RAM/ROM Assembly
A28 09845-66528 9845B/C
Language RAM/ROM Assembly
A29 09845-66529 9845B/C
Peripheral RAM/ROM Assembly with support for 09845-66590 512K R/W Memory Expansion (firmware upgrade)
A34 98770-66534 9845B/C
Alpha Control (98770A, 98780A)
  09845-66540 9845A
LPU ROM Drawer
A42 09845-66542 9845B/C
LPU ROM Drawer
A44 09845-66544 9845B/C
PPU ROM Drawer
  09845-66545 9845A
PPU ROM Drawer
A46 09845-66546 9845B/C Opt. 200
Language RAM/ROM Assembly
A90 09845-66590 9845B/C
512 kBytes R/W Memory Expansion

Fast Bit-slice LPU (Steamer)

Assembly HP Part No. System Description
A30 09845-67930 9845B/C Opt. 200
Bit-Slice Language Processor - Memory Controller
  09845-66536 9845B/C Opt. 200
Interface Assembly
  09845-66537 9845B/C Opt. 200
Data Path
  09845-66538 9845B/C Opt. 200
Processor Control
  09845-66539 9845B/C Opt. 200
Interconnect Panel "Father Board"

Power Supply (PSU) Assemblies

Standard PSU

Assembly HP Part No. System Description
A80 09845-67980 9845A/B/C
Power Supply Assembly
A81 09845-66581 9845A/B/C
Primary Power Assembly
A82 09845-66582 9845A/B/C
Internal Power Assembly (PSU Motherboard)
A83 09845-66583 9845A/B/C
Logic Voltage Assembly ±18V, ±12V, +7V, +5V
A84 09845-66584 9845A/B/C
Motor Voltage Assembly ±17V, +13V
A85 09845-66585 9845A/B/C
Regulator Assembly

Option 200 (Fast LPU) PSU

Assembly HP Part No. System Description
  09845-67981 9845B/C Opt. 200
Power Supply Assembly (Fast LPU)
  09845-66517 9845B/C Opt. 200
Logic Voltage Assembly ±18V, ±12V, +7V, +5V
  09845-66518 9845B/C Opt. 200
Internal Power Assembly (PSU Motherboard)
  09845-66519 9845B/C Opt. 200
Motor Voltage Assembly ±17V, +13V
  09845-66520 9845B/C Opt. 200
Primary Power Assembly
  09845-66534 9845B/C Opt. 200
Regulator Assembly

Printer Assemblies

Assembly HP Part No. System Description
A51 09845-66551 9845A/B/C
Printer Control Logic
A53 09845-65553 9845A/B/C
Interconnect Assembly
A55 09845-66555 9845A/B/C
Motor Control & Graphics Interconnect Assembly
  09845-67951 9845A/B/C
Printer Bucket
  09845-67952 9845A/B/C
Print Mechanism Assembly (with label)
  09845-67163 9845A/B/C
Print Head
  09845-67161 9845A/B/C
Print Head Module
  09845-67954 9845A/B/C
Paper Advance

Keyboard Assemblies

Keyboard Tape

Keyboard & Tape Drive Assemblies


Assembly HP Part No. System Description
A5 09845-66505 9845A/B/C
Bezel Interconnect
A32 09845-66532 9845A/B/C
Keyboard Logic
A61 09845-66561 9845A/B/C
Cartridge Drive Logic
A62 09845-67962 9845A/B/C
Cartridge Drive
  09845-68000 9845A/B/C
Keyswitch Assembly (without keycaps)
  09845-67155 9845A/B/C
Keyswitch Assembly (with keycaps)
  09845-68800 9845A
Keyboard Assembly Complete incl. 1 Transport

9835A/B Mainframe Assemblies


9835A Mainframe


9835A Assemblies with Keyboard removed

Assembly HP Part No. System Description
A11 09835-66511 9835A/B
CPU Assembly
A12 09835-66512 9835A/B
ROM Interconnect
A13 09835-66513 9835A/B
System ROM
A24 09835-66524 9835A/B
128K R/W Memory
A71 09835-66571 9835A
CRT Interconnect
A81 09835-66581 9835A/B
I/O Backplane
  09835-69551 9825A/B,9835A/B
PSU Regulator
  5201-1403 9835A/B
Option ROM

9835A/B Keyboard Assemblies

9835 Keyboard

9835A/B Keyboard, Tape & Printer Assemblies


9835A CRT Display

9835A CRT

9835A CRT Assemblies

Assembly HP Part No. System Description
A71 09835-66571 9835A
CRT Motherboard
A72 09835-66572 9835A
Alpha Control
A73 09835-66573 9835A
Display Logic
A74 09835-66574 9835A
CRT Analog
A75 09835-66575 9835A
High Voltage

98750A Standard CRT Monitor Assemblies


98750A Standard Monitor Assemblies

Assembly HP Part No. System Description
A71 09845-66571 98750A
CRT Motherboard
A72 09845-66572 98750A
CRT Transistor Assembly
A73 09845-66573 98750A
Display Logic
A74 09845-66574 98750A
CRT Analog
A75 09845-66575 98750A
High Voltage
A76 09845-66576 98750A
CRT Interface
A77 09845-66577 98750A
Graphics Scanner
A79 09845-66579 98750A
Graphics Control & Memory
  09845-67701 98750A
Intensity Control

98780A Enhanced Monochrome CRT Monitor Assemblies

Assembly HP Part No. System Description
A12 98780-66512 98780A
Sweep Assembly
A14 98780-66514 98780A
Sweep Assembly
A21 98780-66521 98780A
Display Logic Assembly
A31 98780-66531 98780A
I/O Logic Assembly
A32 98780-66532 98780A
I/O Logic Assembly
A51 98780-66551 98780A
Graphics Logic Assembly
A52 98780-66552 98780A
Graphics Logic Assembly
  98780-66511 98780A
CRT Drive Assembly
  98780-66513 98780A
Heatsink Assembly
A34 98770-66534 98770A/90780A
Alpha Control
  98775-66504 98770A/98780A
Light-Pen Control Assembly

98770A Color CRT Monitor Assemblies

Assembly HP Part No. System Description
A0 98770-66500 98770A
A1 98770-66501 98770A
Motherboard (old version)
A2 98770-66502 98770A
Convergence Waveform Assembly
A3 98770-66503 98770A
Convergence Output Assembly
A4 98770-66504 98770A
Deflection/HV Assembly (old version, see 98770-66544)
A5 98770-66505 98770A
Transistor/Heat Sink (Exchange Part 98770-69505)
A6 98770-66506 98770A
Video Amplifier Assembly (Exchange Part 98770-69506)
  98770-67980 98770A
Power Supply Assembly
A7 98770-66507 98770A
PSU Primary Transformer Assembly
A8 98770-66508 98770A
PSU Filter Capacitor Assembly
A9 98770-66509 98770A
PSU Control Assembly
  98770-66515 98770A
PSU Switching Transistor Assembly
  98770-66516 98770A
PSU Rectifier Assembly
A11 98770-66511 98770A
Vector Generator Assembly (Exchange Part 98770-69511)
A13 98770-66513 98770A
Display Logic Assembly (old version, see 98770-66533)
A32 98770-66532 98770A
Graphics Memory Assembly (Exchange Part 98770-69532)
A33 98770-66533 98770A
Display Logic Assembly (Exchange Part 98770-69533)
A34 98770-66534 98770A/90780A
Alpha Control
A44 98770-66544 98770A
Deflection/HV Assembly (Exchange Part 98770-69544)
A53 98770-66553 98770A
Display Logic Assembly (Katakana old version, see 98770-66554)
A54 98770-66554 98770A
Display Logic Assembly (Katakana, Exchange Part 98770-69554)
  98770-67901 98770A
High Voltage Assembly
  98770-61608 98770A
Start-up Transformer Assembly
  98770-90303 98770A
Display Logic Assembly
  98775-66501 98770A/98780A
Light-Pen Control Assembly (old version, see 98775-66504)
  98775-66502 98770A/98780A
  98775-66504 98770A/98780A
Light-Pen Control Assembly (Exchange Part 98775-69971)