Don't neglect them while troubleshooting, especially the little red bastards. :-) My HP 2647A graphics terminal developed what appeared to be a sync problem when displaying more than one line of text. Swapping the suspect cards with known good ones from another terminal didn't change a thing. All self-tests passed, including text RAM and graphics RAM. Graphics mode worked perfectly. I finally swapped the two RAM cards (32K on each), changing the DIP switch configurations on each. At last, a RAM error. I excercised all of the DIP switches, put everything back together and it worked. This is the second time I've had problems with DIP switches in vintage HP gear. The other was in a 2117F I was working on for Dave McGuire. Same cure. Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/