In my PX4 are
2 EPROMs. One is the standard utilities ROM (PIP, STAT,
CONFIG, etc). The other seems to be the drivers for this RAMdisk. It is
in one of the carriers, but it's a hand-labelled ROM and looks to have
been crimped into the carrier by hand, not with one of the press tools.
Maybe a prototype or a low-volume product.
The roms in mine seem to be hand-labeled too, I think there are three
Are you talking about a PX4 or a PX8?
Both contain 3 ROMs, actually, but on the PX8, one is under a seperate
plastic cover on the bottom of that machine. That one, and the one on the
far right as you look at them in the PX4, is the OS/boot ROM/etc, and is
never normally changed (it's not in one of those carriers, it goes in a
normal DIL socket). The other 2, in carriers, appear as read-only 'disks'
to CP/M.
In my PX8, I have one ROM with the CP/M utilities (PIP, STAT, etc) and
one with BASIC. In the PX4 I have the utilities and the RAMdisk cartridge
drivers.
altogether. There's a "wedge" on the
machine, which I think has its own
The wedge is normally extra RAM which appears as a RAMdisk. On the PX8,
there was also a modem (300 buard), or a combined modem/RAMdisk unit. On
the PX4, I think the modem was a cartridge.
battery besides the main one and I think there's
also one other one inside
there someplace, it's been a *long* time since i peeked in there. I'd
The RAMdisk units do contain their own battery.
The machine itself contains 2 batteries. In the PX8, there's the main
battery pack (4 sub-C NiCds) and a separate 4.8V backup NiCd soldered to
the PCB. In the PX4, there's the main battery (either a back of 4 AA
NiCds connected to the 4 pin plug in the battery compartment, or 4 AA
primary sells fitted by rearranging the contact boards), and a separate
backup NiCd fitted inside the case and plugged into the PCB.
Considering I am not likely to use these machines every day, I find
recharageable battereis to be a pain. They are going to self-discharge in
storage and need charging before I can use it, they are going to fail
long before they should due to neglect. I've been running the PX4 on
alkaline AA primary cells anf the PX8 off my bench supply. Yes, I have to
do a hard reser every time and reset the configuration, but...
-tony