Epson PF10 problems

Tony Duell ard at
Fri Dec 23 16:48:47 CST 2005

[PX8, etc ROM carriers]

> Interesting tidbit that they were used in those other machines,  I didn't know 
> that.

About 20 years ago, back when Maplin (UK Electronic shop) actually sold 
enough components to design something with, and when ZX81s were still in 
use, I designed an interface for the school's 81 (8 bit ADC, digital I/O 
lines). I used some connectors that Maplin called 'Multicon', but which 
were actually Molex 0.062" things. 

Anyway, Maplin were out of stock, and didn't know when they'd get any 
more. I actually called Molex to ask if there were any other distributors 
for said connectors, and they gave me some names and sent me their 
catalog. I am sure those carriers (and the sockets they fit into) were in 
there. In fact I think I asked many of the distributors if they carried 
them. None did from what I remember. 

I wonder if they were almost a standard at one time.

> > 2) Is the PX4 technical manual on the net anywhere (I've found the PX8
> > one already).
> Do you have a link handy?

It's on Bitsavers (, but use one of the listed 
mirror sites if you can). Go to the document archive, it's in the 'epson' 
directory. Warning: It's big!

> > The thing I need most at the moment is the pinout of the cartridge
> > connector. I have a 3rd party 512K (!) RAMdisk module there which doesn't
> > seem to work.
> First I've heard of any third-party stuff for that machine as well.

I don't know the origins. It was in the machine when I bought it at a 
radio rally (hamfest) about 15 years ago. From what I rmember, the seller 
had a pile of them, I think all the same spec.

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.


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