HP 82143A Internal view
This printer can be opened by loosen 5 screws. One screw is clearly visible on the back, the other four screws are hidden behind the rubber feet.
The picture above shows an opened printer, seen from the back side.
All electronics are build on one PCB. The discoloration on the left top is caused by heat.
At this spot the power resistor is located that controls the charging current for the battery pack.
A nice detail is the reflective wheel to synchronize the printer speed with the electronics.
On the PCB the next integrated circuits were found.
| HP part number | Description | Equivalent | datasheet |
|---|---|---|---|
| 1810-0037 | Resistor array 8 x 1K | ||
| 1820-1016 | Dual driver | SN75453BP | download |
| 1820-1641 | Hex buffer | SN74LS365AN | download |
| 1820-2280 | Processor | MK3870 | download |
| 1826-0287 | Quad comparator | LM2901 | download |
| 1858-0056 | Quad transistor array | NTE2322 | download |
HP 82143A internal related links:
- HP 82143A Service Manual
- HP 82143A Schematic
- HP 82143A Schematic by Tony Duell
- Forum discussion: Repairing an HP41 printer?