This is a pretty easy project and though it won't make a night or day difference, any little speed gain helps. This
"Tune up" was explained to me by Guru Richard Bell. As you know this board is what attaches the console to the PEB, and
with projects like the crystal upgrade or 32K on the 16 bit bus which speed up the console, getting that data to and from
the PEB just a little bit quicker can't be a bad thing!
Keep in mind that is mod is more about "bottle neck relief" than speed increase for a stock console.
In other words this mod serves to allow higher speed in conjunction with the 16 bit memory speed and
overclocked crystal speeds. This is one of those projects where you may not see much, if any, advantage, but
for about $2.00 in parts, and about 30 minutes soldering it really can't hurt!
What we are doing here is replacing the 3 74LS244 buffers with 3 74HCT244 buffers. Make sure that the new 244's are marked
HCT. These are "HIGH SPEED" buffers and the T makes them compatable with TTL inputs. While you are at it for a
few cents more go ahead and replace the two electrolytic capacitors as with the age they are at
they probably are drying out.
I have all the parts in question marked by yellow boxes in the pictures below.
So what you will need are:
3 - 74HCT244 IC's
4 - 22 uf electrolytic capacitors 25v-35v (35v preferred)
Please make sure that all wiring and soldering is double checked before re-applying power.
Though computer components are pretty hardy some do not take to being
wired up backwords or incorrectly. I have done my best to make sure that all diagrams
and instructions given here are correct, but I can not be responsible for any damage
an incorrect upgrade might cause.
Desolder the parts shown, and take care not to remove an of the foil.
Replace with the new parts, paying attention to the
orientation of the chips, and the polarity of the capacitors, see figure 1.
There are also two of the same type capacitors located in the end of the flex cable that plugs
into the console that should also be changed, see figure 2.