------------------------------
     HOW TO EXPAND YOUR VDC RAM
   ------------------------------

This file by (C) 1988 by Regnad of Regnads Realm BBS.  Okay to upload,
download and store in any manner as long as this message is retained.

   Before we get started there is one thing you need to know.  If your unit is
still under warrantee this proceedure will void that warrantee!

   You might be asking what the heck is VDC?  I'm glad you asked that
question, because there are other people that don't know either.  VDC RAM is
the RAM the C-128 uses to hold the characters displayed on the 80 column
screen.  You heard about VDC RAM in the last L-BUG Bytes (refer to the Sept 88
edition).  Ok what exactly are we talking about?  The specialized RAM for the
VDC chip, THAT'S what!  Don't worry if you still don't know what I'm talking
about, because we'll talk more about that later.  Just take it for granted
right now that there is a chip dedicated to displaying the 80 column
characters called the VDC or Video Display Chip.

  This chip has a 16k byte area for the storage of characters that are to be
displayed to its screen.  There is NO program that you can load from disk
directly into this area.  This area is updated by a special ML routine.  It
has to use the VDC to access it.

   What we will do is make more room to put more junk in there so we can do
different things!  Right, maybe even seriously Strange things!

 What do we need to get started?

   We will need two chips called Dynamic RAM chips.   Their number is 4464. 
These are 18 pin dip chips.   You can also get some good 18 pin dip sockets
but they really are optional.  Optional if you never want to take the 64k
chips out and put the 16K back in there.   For this demonstration we are going
to put the sockets in and you will be able to see how this is done.  We also
need some tools, such as the following:

a desoldering tool or solder wick
a soldering iron
some rosin-core solder
a philips screwdriver
a quarter
and if you have one a chip insertion tool would be nice.

   Now what?  Ok what we need to do now is turn off the computer.  You may
leave it on if you like serious surprises like electrical shock, but I
reccommend strongly that you might want to turn it off.  Disconnect the cables
to your computer and turn your computer keyside down.  Take out the screws
that hold the case together.

Once you get inside there is a metallic case in the back part of the circuit
board.  I took mine off and left it off.   This is where the quarter comes in
handy.   Take the quarter and tape it to the metallic case and throw it as far
as you can.  Now you have only lost a quarter and the case will NEVER bother
you again.  Once under the case you'll find a large chip that says 6385 on it
somewhere.   That is the VDC chip.   It should have 40 pins or something like
that.  Nearby that chip you will find two smaller 18 pin dip chips.   They
should be numbered 4416.  There might be some small difference in the number
there, but those two guys will be the chips you need to remove.  BE CAREFUL to
notice on the chips where the little dimple on the chips is pointing.  This
will tell you where the number one pin of the chip is and you need to replace
them with the new chip pointing in the same direction.  Now very carefully so
as NOT to damage the motherboard, remove the chips and replace 'em with the
sockets.  Ok, so now what are you waiting for?  Install the 4464's in the
sockets being sure you have the dimples in the chips pointing in the same
direction that the old chips were, make sure that everything is clean in and
around the sockets, you know the old thing...  look for shorts, blobs, longs,
cold solder joints that sort of thing....  When you are sure there are none of
that kind of nastiness in there then you are ready to close that case back up.


[PRESS RETURN]: