Skip to main content
Home Forums 68kMLA Quadra 840av ROM SIMM? — #6
Post #6 by dougg3
Source Forum68kMLA
CategoryTroubleshooting
Post DateFri, 7 Sep 2012 - 02:18
Original URLhttps://68kmla.org/bb/threads/quadra-840av-rom-simm.23986/
Post
Ya know, I'm not sure on that! I can definitely solder a socket onto the motherboard, but I don't know what it takes to make it work. My SIMM would need a hardware mod at the very least.

The Quadra 700 is able to detect that a ROM SIMM is inserted and automatically disables the onboard ROM. My uneducated guess is that it uses one of the VCC pins on the SIMM to override a weak pull-down resistor on the soldered ROM chip select or output enable lines (thus pulling it high and inactive), but I don't know. I suppose I could check the 840av's motherboard out and trace some things, but it's such a pain to get the motherboard out that I probably won't be working on that anytime soon :) I've already broken the clips that hold the CD bezel on (such brittle plastic!)...grrrr....

mp.ls