It does sound like there might of been some static damage on the board. The ROM shares lines with the RAM wonder if a RAM has fried? Or a buffer?
On the M100 the Vdd, Vee, Vb and GND lines are marked so it is quite easy to check the +5, -5V & +3.6V are on the board OK. ________________________________ From: M100 <[email protected]> on behalf of Greg Swallow <[email protected]> Sent: Tuesday, June 5, 2018 02:59 To: [email protected] Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install For sure Josh. Checked continuity after installing the two SIP rows. Have also checked since from top of chip leg through motherboard and sounds good. Will have to check the M100 Service Manual for some reference VDC check points. I had this happen with my first M102 mod and re-flowing the solder took care of it, but not doing it this time. Am afraid I fried something. Don't see any evidence, but I did get a solder cross between pins on a neighboring IC. Caught it and cleaned it before I re-assembled the M102. Have a new magnifying light now to help. What I had was small and not enough for my failing eyes -- I see a ring of five of everything. Trying to get it done before eyes get much worse. I also have five M100 to do with Mike Stein's PCB and three or four of those will hit eBay. God Bless, GregS <>< ----- Original Message ----- If all you have is a MM, I'd say the next step is to verify continuity to the ROM chip. Measure for continuity from the metal of the ROM chip leg over to the corresponding leg on a RAM chip or the CPU. Make sure your socket is working correctly. -Josh
