By the first sorry if I write in English - I'm from Italy - barely read your messages by guess but writing or
using google translation seems not ok fo rme, since one time found Your group resolutive I try again...
Hi, I found one of such multimeter at a flea markt but the eprom 27c256 is gone (reads all 00s) does anyone have a rom image (the eprom label is: U212 DMM).
The multimeter logic board have the space for the installation of the 488 interface, but without components, probably for the '488 model will be useful a different rom. (the 2510G model) The interface between the multimeter logic and the 488 interface is made by two optocoupler so a simple two way, two wire link (interesting, may be connected to an external micro w/o 488 ...) I not will bad have a service manual(the schematic will be ok), but curiously its easy found a really old servman (the '5xx tubes scopes) but not this one...(maybe oldies products lasted more longer than newest?) The logic is based on a 8031/2 micro (one time my preferites) instead of dedicated chips and also the 488 interface(my guess), in this case a simple 7106 may be replaced with another one but with micro the hardware is not the all ! (fortunately is external rom)
Can someone help me? bye & TIA delo