🚀 go-pugleaf

In article <359@web.cme-durer.ARPA> paisley@cme-durer.ARPA (Scott Paisley)
writes:
>	Next question.  How many layers are the simm boards anyway?
>2 layer?  4 layer?  Actually what I'm trying to find out is, would it
>be possible to use the old 256 simms in my MacPlus, remove the old 256
>chips and put in the the 1M chips in there place?  Is this cheaper? Can
>someone who can hold a solder iron do this?  It seems that one could get
>chips alot cheaper than simms and save some bucks.  But is it worth it?

Two layer on the ones I've seen.

The new chips will certainly have a modified pinout, perhaps just an extra
address line.  This would entail more surgery to the SIMM boards.

The 1M chips that you are likely to find commercially are DIPs.  SIMMs use
extra small surface-mount chips with a J-lead design.  You will find them
hard to locate inexpensively in small quantity.  The pins on a surface-mount
chip are twice as close together as normal DIP pins.  The J-lead and close
chip-to-chip spacing make this operation very difficult.

You might be able to do it.  As a youngster, I performed microsurgery on
1/4-inch 7-segment LED arrays and got good results.  This sounds harder.

The best approach is to use real 1M SIMMs.  You can combine one set of these
with half of the existing 256K SIMMs and make 2.5 Mbytes.  Give the extra
256K SIMMs to a computer hardware hacker who will thank you profusely.