HP 2671 Graphics ROM

-----Oorspronkelijk bericht----- Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] Namens Tony Duell Verzonden: zaterdag 20 maart 2010 19:07 Aan: cctalk at classiccmp.org Onderwerp: Re: HP 2671 Graphics ROM board, the one This sounds as though it might be a different cersion of the HPIB board, but I'll give the numbers in a second. can compare. OK, I've dug my 2671G out and taken it apart. I find the instructions on the bottom very amusing. They tell you 'no user serviceable parts inside' and then tell you just how to take the cover odd. Go figure... Anyway The PSU is a 02670-60070. I would be suprised if there are any changes there. The HPIB interface is 02670-60072. U14 (2016 RAM) and U15 (ROM) are not fitted. U2 (an 8049 microcontroller) is 1820-2833. The DIP switches are set : 1 Open (Mode) 2 Open )2K) -- this has no effect if U15 is not fitted! 3 Closed (Int ROM ) -- this means the 8049 will run from its internal ROM 4 Open (Test) The printer PCB (on the back of the thermaal print mechansim) seems to be iether a 02760-60067 or 02670-80084. U3091 (8049) is 1820-3096 U101 (ROM) is 1818-1819 There is a 10 way dIP switch set as follows : 1 Open 2 Open 3 Closed 4 Open 5 CLosed 6 Closed 7 Open 8 Closed 9 Open 10 Closed If I am reading the scheamtics properly : SW8 -> 8049 will run a program from it's internal ROM SW10 -> power-fail or watchdog tinme-out will casue a rest Others -> 8K esternal ROM (A12 is used), but note thatsince SW2 is open, PSEN/ does not enable the ROM. This means that the ROM is for data storage (font?) only, not for program code. Unfortunately I don't ahve an 8049 programmer at the moment. It's something I must get roudn to buidling. Which means I can't dump the microcotnrollers... -tony