YORKE annunciator - HP-48/49

[TomC]

I believe the annunciators are independent of the multiplexed LCD drivers, but we need a better schematic of the HP48.

TomC

(08-15-2016 09:29 AM)Peter HOFMANN Wrote:  I wanted to ask, if anyone knows the number of the output pins of the YORKE corresponding to the annunciators (right shift, left shift, alphabetics ...) for indication on the lcd-display OR the pin numbers on the lcd-display for the 6 annunciatorrs ?

May be there is a common line + 6 lines connecting the YORKE with the lcd display ?

For the annunciators indication on the lcd are the corresponding bits on the adresses 0010B/0010CH to be set/reset, especially Bit 3 in address 0010CH for the basically switching ON for the annunciators.

The effect could be, that the key sequences for the annunciators are working okay, but WITHOUT indication on the lcd display ! YORKE output port defect ?

Information appreciated
Peter