HP-41 external big display. (just kidding... sort of)

[Diego Diaz]

Hi all,

The annunciators are already there: twelve small arrows under the digits.

Some lettering must be added on the bottom to show the different functions: USER, BAT, Flags, PRGM, ALPHA, etc.

The display interface chips are the same used in the 41, hence it can be connected to the lines from any I/O port.

Some resistor divider must be included to provide the required V1, V2 and V3 to the LCD. But apart for that, a limiting resistor for the Vcc line and a 470pF capacitor for the internal oscillator; only standard signals are required: Phi1, Phi2, SYNC, ISA, DATA and PWO.

These type of displays are used (with different annunciators) in several instruments from that era, e.g. 3468 & 3478 DMMs.

Enjoy your week!

Diego.