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 Mainframe 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 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
9835A/B Keyboard, Tape & Printer Assemblies
9835A CRT Display
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 | Motherboard |
| 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 | Light-Pen |
|
| 98775-66504 | 98770A/98780A | Light-Pen Control Assembly (Exchange Part 98775-69971) |