gnome@oliveb.UUCP (Gary) (08/23/86)
> To put in another graphics board you must first disable your present board. To > do this you remove a 74LS00 chip located on the bottom middle of the graphics > board. It is above where the +5 volts and ground wire connect. In newer > machines it is in a socket on older ones it is soldered in. NOTE this will > void your warranty if you do it yourself! After removing the chip then pins 7&6 > must be jumpered together and 3,8,11,14 must all be tied together. We got > this fix directly from AT&T. We just bought 300 of these units and some will be > modified. > All the usual disclaimers, ect... > > Paul L. Marcuzzo > Penn State University Well, actually, on REV P4 boards (theoretically all rev's that don't have the 3-pin disable jumper) you should try removing the LS00 and connect 3,11,14 together and 7 & 8 together. This should disable both the IO and memory address decoders and leave the bus clear for other display controller cards. You shouldn't be able to boot-up with the other configuration... Gary >- Usual disclaimer -< (hplabs,allegra,ihnp4,glacier)oliveb!oliven!gnome
gnome@oliveb.UUCP (Gary) (08/26/86)
> Well, actually, on REV P4 boards (theoretically all rev's that don't > have the 3-pin disable jumper) you should try removing the LS00 and > connect 3,11,14 together and 7 & 8 together. > This should disable both the IO and memory address decoders and leave > the bus clear for other display controller cards. > > You shouldn't be able to boot-up with the other configuration... > > Gary > > >- Usual disclaimer -< > > (hplabs,allegra,ihnp4,glacier)oliveb!oliven!gnome > One other thing, which I just found out -- If you can't boot with the add-on display controller in place, you will probably have to set DIP switch 7W (closest to the back of the machine) to "No controller mode". Switch 1 2 3 4 5 6 7 8 - - - - on on - - Don't forget to write-down the original switch settings! Good luck! Gary