ZN wrote: > On 30/04/02 at 23:01 henk verbeek wrote:
> > Does anyone know how to upgrade the memory of a standard (classic) > > ql ? I have searched the net but i didn't find a circuit or > > anything. Are there no do it yourself circuits available ? > Done it many times in many ways. By far the simplest is to find a > 628512 (aka 614000) static RAM chip, usually comes in a 32-pin > surface mount package but regular DIP 32 is also available. This is > 0.5MB in a single very low power chip. In addition, you need two > 100nf capacitors, one 74HC153 logic chip and one 1N4148 diode. > If you want to put this RAM expansion into one of the ROM chip > sockets (plus the few extra wires you need), you can take both ROMs > and put them 'piggyback' one onto the other, carefully solder the > pins together (do this with pins facing up so solder does not go > onto the pins of the chip that will plug into the socket), and plug > the combination into any one of the two ROM sockets. It is quite possible that I still have a few built and ready to go, eprom adapter boards that place the entire ROM on one CMOS EPROM that you would just plug into your motherboard. That goes a long way towards freeing up both one of the ROM sockets and and at the same time, reduces the total power requirements a measurable amount. (runs cooler) The boards I have also provide a battery to hold clock time between power cycles, works most all the time. -- Paul Holmgren Hoosier Corps #33, L-6 2 57 300-C's in Indy
