Epson PF10 problems

[Roy J. Tellason]

On Tuesday 27 December 2005 08:20 am, Tony Duell wrote:
> > I don't think this one has BASIC in it.  There are eproms,  Portable
> > WordStar,
>
> Probably not if you have wordstar. There are only 2 EPROM sockets, BASIC
> fills an EPEOM, I think wordstar would as well.

The wedge has a socket,  too.

> The EPROM you really need is the utilities one. Without it, you don't
> have PIP, and therefore no way to copy files.

I think nsweep might be in there,  though I'm not sure,  it's been too long.

> From memory, a PX8 has the following connectors :
>
> A coaxial power connector for the charger
>
> An 8 pin mini-DIN 'serial' port for the disk drives. It can also be used
> for a printer, but only at a cery limited selection of baud rates. It is,
> at least, at RS232 levels. Only 5 pins are wired (ground, TxD, RxD,
> handshake out, handshake in, the latter being on the pins used on the
> RS232 poer for DTR and DSR).
>
> An 8 pin mini-DIN 'RS232' port  All pins usedm you get the normal
> hardware handshake lines.
>
> A 3.5mm stereo jack socket (like a 'walkman' headphone socket) 'BCD'
> port. This is for a BarCoDe reader, the connections being ground, signal
> and +5V power out from the PX8. From what I can see the signal goes both
> to one channel of the ADC chip and to a pin on one of the gate arrays
> which contains logic to measure the time between transitions of the
> signal. Note there's no barcode software in the BIOS ROM

Sounds about right.

> Another 3.5mm jack socket 'ADC In'. This is an analogue input to another
> channel of the ADC chip, the other connecitons being ground and a
> TTL-level trigger signal

It'd be nifty to see if I can find some use for them,  once I get it working.

> A 3.5mm mono jack socket 'SP out' for an external loudspeaker.
>
> A 50 pin header 'System Bus' which is essentially the unbuffered Z80 bus
> lines.

I think that's what the wedge connects to.

> > > You can turn it off with the little switch inside the main batter
> > > compartment. The machine should run from the main battery (or a 5V PSU
> > > connected in place of the main battey) if there are no otehr problems.
> >
> > To the battery connector?  Ok...
>
> Connect a _reguylated 5V PSU_ (nothing else)  to the battery connector
> inside. I mentioned where to get the sockets in an earlier message, you
> can get the polarity from the technical manual or by examining the NiCd
> pack.

I *made* that pack,  the one that came with it was shot.  I also used to run a 
retail battery store,  and salvaged a whole bunch of similar connectors from 
cordless phone batteries that folks brought in for replacement,  and I'm sure 
that one of those will work.

A regulated 5V supply should be no problem for me.

> I will emphasise this again because it's important. There is no regulator
> circuit between the battery and the standby supply line (maintains RAM,
> real time clock, etc when the machine is turned off) or, indeed the main
> logic supply line. Do not connect an unregulated supply here, you will
> wipe out chips throughoug the machine.
>
> > > Do remember there are no regulators in the PX8 PSU. The power supply
> > > must be close to 5V (4.8V is OK), not a random unregulated one. You may
> > > well do a lot of damage with the latter.
> >
> > Are you talking about going right into the battery input connector?  Or
> > to the charger input on the rear of the machine?  The "power supply" I
> > use with it is a wall wart,  I don't recall what it's rated at,  but it's
> > labeled with that dymo tape stuff as being for that machine,  came with
> > it when I got it.
>
> The wall-wart is an unregulated thing. Claimed to be 6V 600mA on the
> label (and in the manual), in reality it's nearer 12V off-load. This
> charges the main battery, and the machine depends on the fact that the
> the battery will clamp the voltage to 4.8V or so to limit the voltage on
> the logic supply lines. Do not, I repeat, use that PSU in place of the
> battery, do not, in fact, plug it in without as good battery in place
> (there is a proteciton zener diode, but I don't trust it!)>

Hm.

> I run mine from a regulated electornic workbench supply connected in
> place of the battery (and set between 4.8V and 5V). I would think the 5V
> supply from another computer would be OK (e.g. an old PC power supply),
> but I've not tried it, so don't blame me if you kill all the ICs in the
> PX8...

I have enough 7805s and similar to deal with that,  for sure.

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