24 Jul
1998
24 Jul
'98
2:25 p.m.
Date:
Sat, 25 Jul 1998 00:08:37 +0100 (BST)
Reply-to: classiccmp(a)u.washington.edu
From: ard(a)p850ug1.demon.co.uk (Tony Duell)
To: "Discussion re-collecting of classic computers"
<classiccmp(a)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...
Jason D.
jpero(a)pop.cgocable.net
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(a)pop.cgocable.net