annoying that they missed the part number from the bench briefs listing HP-Bench-Briefs-1990-07-12.pdf available on www.hparchive.com Dave Caroline

Well, I am not convinced it is totally custom, in that it has the DP8367 number as well as the HP1820-xxxx number (nost totally custom chips only have the latter). I can well beleive it's a custom version of a standard CRT controlelr, perhaps for a different screen format or something. Anyway, I did a little more poking isnide my HP120 today. I believe the DP8367 is closely related to the DP8350. Some of the pinouts machine up (and not just bovious ones [1]). The internal registers seem to be loaded in the same way _from the address lines_. It is connected to am 80 yte shift register chip (I forget the number, MM5035??). [1] For example, according to the HP125 boardswapper manual on hpmuseum.net, one of the output ports on the terminal processor (a Z80A) controls the 6 self-test LEDs and a line to the video controller to select 50Hz or 60Hz vertical frequency. I can find this output port (an 8 it latch) on the the the terminal PCB, the bit that would set vertical freuqencty is linked to a pin on the video controller chip, indeed on the DP8350, that pibn does select vertical frequency) Now, I can find _references_ to the DP8350 data sheet, but not the complete data sheet. Does anyone have that one? -tony