In message
<aanlktimvnyo+fgsgvbzk1jdmmazo-pbb+uwphrxnb...@mail.gmail.com>, Plastic
<plasticu...@gmail.com> writes
The ZIF carrier would be a neat way of doing it.
The BBC Micro also has a slot, to the left of the keyboard area, for
this purpose (it is a perforated).
It is normally covered over, so most people would not notice it being
there.
For Lee's project with the QL, a PCB taking 4 ROM's with a ZIF, would be
neat way of getting easy access to alternative ROM's.
If there's enough demand, I would be happy to make a few of these boards -
though they would be "prototype" PCBs and fairly expensive. Short run PCBs
tend to run around $40 each just for the PCB. Everything else would be
around $10. It might be easier to have more than one QL.
On the upside, ZIF sockets would make things easier.
At Sandy, we had one of the QEPIII programmers, which we used to program all
the EPROMS in everything we made. We also had a ZIF carrier which could hold
four ROM sets. It didn't just switch the CL lines - it unpowered the
unwanted slots, because once we put four Sinclair plastic-cased ROMs in
there and the current draw was too much and popped something in the power
section! Weird.
Dave
On Sat, Feb 12, 2011 at 6:16 PM, Peter Graf <pg...@q40.de> wrote:
Hi Lee,
> So I need to look out for a Gc, SGC or Minerva conversion kit,
> haven't seen those on eBay or sell my retro
For Minerva ROM you could try
1. Get an M27C512 and a 28 pin DIL socket (wide, long pins)
2. Program lower 48 KB with Minerva, and upper 16 KB with extension ROM
binary of your choice
3. Lift up pin 1, 20, 22.
4. Press M27C512 into an IC socket
5. Wire socket pin 20 to M27C512 pin 1
6. Wire socket pin 22 to M27C512 pin 20
7. Wire M27C512 pin 28 to M27C512 pin 22
8. Remove both QL ROMs from socket
9. Press in the M27C512 with it's socket into one of the QL sockets
All the best
Peter
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