Epson QX-10, CP/M

From: jpero_at_pop.cgocable.net <(jpero_at_pop.cgocable.net)>
Date: Fri Jul 24 21:25:40 1998

> > Date: Sat, 25 Jul 1998 00:08:37 +0100 (BST)
> > Reply-to: classiccmp_at_u.washington.edu
> > From: ard_at_p850ug1.demon.co.uk (Tony Duell)
> > To: "Discussion re-collecting of classic computers" <classiccmp_at_u.washington.edu>
> > Subject: Re: Epson QX-10, CP/M
>
> > The QX10 is a very nice CPM machine IMHO. I bought a couple at a
> radio
> >
> > The disk drives (1/3 height) are _strange_, BTW. They've got linear
> > postioners to move the heads, not stepper motors. Details of them are in
> > the tech manual, but alas all the interesting stuff is inside a couple of
> > ASICs on the drives.
>

Ooops! I wanted to comment on this too... when you move the heads
back and forth did you find soft detents rather like stepper? Then
this is really linear stepper type. These drives uses push-push
latching via that flip down door with LED window. Push once, door
opens, put disk in and push door shut to clamp down a floppy disk.
Push once again, door flips down and the disk pops out.
Is that it? This is same type as I have on Zenith and Morrow Pivot
had.

> Snipped of interesting tales...
>
> > Then it hit me. There were no defective components on either video board
> > (or anywhere else in the machine). There were no components missing. Now
> > was there a design bug.
> >
> > What there was were 16 components present that shouldn't have been -
> > 0.1uF decoupling capacitors on pin 9 of the DRAMs. When I used pin 9 as
> > the A7 address input, the resulting 1.6uF capacitance loading the driver
> > completely skewed the timing. Hence the fault. I desoldered the caps and
> > it worked fine.
>
> that's what I call this leap of intitutive or gut feeling. That
> would applies to this; fixed one motherboard that was hopelessly
> blown by one chipset only on basis of external symtoms that is vague?
>
> Jason D.
>
> Max, hint! I snipped out what not needed and kept the heart of what
> I wanted to comment on. Need to use alterative editors other than
> lynx. Lynx is good for textural surfing but very poor in editing any
> emails via website. I find joe editor program not too bad because of
> online help to help memorize those commands while using it.
> I'm right now using winblows w/ pegasus mail, (I found few flaws in
> that stuipid email program and trying to find a chance to wean off of
> it!) until I get enough stuff fit together to build decent couple of
> linux boxens later on.
>
> Jason D.
>
> > -tony
>
> Jason D.
> jpero_at_pop.cgocable.net
>
>
Jason D.
jpero_at_pop.cgocable.net
Received on Fri Jul 24 1998 - 21:25:40 BST