Epson QX-10, CP/M

From: jpero_at_pop.cgocable.net <(jpero_at_pop.cgocable.net)>
Date: Fri Jul 24 21:11:00 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.

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
Received on Fri Jul 24 1998 - 21:11:00 BST