[comp.sys.ibm.pc.hardware] need help reconfiguring NEAT chipset when adding memory

Q4105@pucc.Princeton.EDU (W.g. Price q4105 Mathtech) (03/15/91)

I need help upgrading a clone without (I now discover) enough documentation.
I am trying to add memory to an 'ABC' brand AT motherboard with the NEAT
chipset .. it has 2 banks of 1 meg dram and I have 2 banks of 256's to
add into sockets which are dual 256/1024.  The machine dies in POST before
spinning the floppies when I try adding the ram before changing the config.
1) Should I reprogram the NEAT extended CMOS -before- powering down to
add the new memory ?  2) Am I misreading the documentation that implies
adding 256's on top of 1024's should be allowed ?  3) What are the special
reset/POST key sequences to get into the extended setup and to bypass
the existing XCMOS registers in case I -really- mess up ?