PDP-8/E MM8EJ G233 Troubles

E1 and E7 do the ma3,4 and 5 decode Dave ----- Original Message ----- From: "Kyle Owen" <kylevowen at gmail.com> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Sent: Friday, January 17, 2014 6:38 AM Subject: PDP-8/E MM8EJ G233 Troubles > Hi all, > > Recently, my PDP-8/E has been acting funny. I finally had some time tonight > to run a memory test and found that all addresses matching the pattern > XX5XX read back all zeros. Everything else tests fine. I swapped the XY > driver board (G233) and found that the problem went away. > > I can't seem to locate a schematic online. My PDP-8/E preliminary > maintenance manual only describes the G227, for the 4k core board. Can > anyone help with a schematic, or judging from the symptom, point me to a > particular area on the board? I've got a 'scope and should be able to > diagnose it if I know where to start looking. > > Thanks, > > Kyle > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2247 / Virus Database: 3681/6511 - Release Date: 01/17/14 >