Tech question: EII+ with Rev. 1 having trouble communicating with Macintosh
2009-11-02 by Rescio
hi all, i bought a EII+ a while ago and it came with some mailfunctioning of the voices. But this is cured by replacing the supercmos ic, i Also reseated every ic, everything works great exept that it can't communicate with a MAC. Yes i did check everything already, mine is a Rev 1 with the RS422 already installed. I ordered a special cable by Rob from EmulatorArchive, have tested it with two Mac's a SE30 running 7.1 OS and a Classic II running 7.0 both with or without Appletalk on/ off. Oh yes the mainboot Eprom is 2.1 for EII+ and the Scanner eprom is 3.0 i use 3.1 OS software, model 6050 serial 1878. I¡¦m beginning to think there is something wrong with the RS422 port ¼ Exept were to look??? I also exchanged the 26LS31 and 26LS32 IC¡¦s (IC132 & 108), did the REV.1 check exept i don't understand one thing, IC107 pin 22 needs a resistor and at the other side +5v If i measure pin 22 without having done this i get a 0.48 v if my REV1 should be mod correct out of the factory, should this be any near +5v instead of this 0.48? at the schematic i see at pin 17 a resistor drawn and +5v, if i measure there i get 3.48v max. Is this correct? could it be that this scn2651 is mailfunctioning, can i replace it just like that or do i need something else? I also post this in the EIII forum, please check the print screen i provided in this post, with leftside the schematic of IC107 and right the REV.1 check Here is the link: http://eiiiforum.com/index.php?topic=393.msg2758#msg2758 I hope someone can help me master this problem, thank you very much :)