16 Jun
2006
16 Jun
'06
2:35 a.m.
Subject: Re: Data I/O Series 22 EPROM Programmer help
From: "Ethan Dicks" <ethan.dicks at gmail.com>
Date: Fri, 16 Jun 2006 13:59:04 +1200
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On 6/14/06, Roy J. Tellason <rtellason at verizon.net> wrote:
It's bipolar and also programable (fuseable links) and they do have
a tendancy to develop shorted paths where they were once "opened".
Allison
We used to do a LOT of c64 repairs way back when,
and every one of those
beasts had a "906114" PLA in it that as I understand it was an 82S100 part.
And it was a very common failure item, resulting more often than not in a
blank screen or perhaps some bizarre display.
Right... it's the address bus manager, among other things. When it
fails, the CPU can't get to RAM or ROM or the VIC-II, typically.
Any idea as to why that should fail so often?
Thermal death? It's a bi-polar part, not *MOS, and it does run hotter
than the rest of the components.
-ethan
16 Jun
16 Jun
10:09 a.m.
On 6/16/06, Allison <ajp166 at bellatlantic.net> wrote:
It's bipolar and also programable (fuseable links)
and they do have
a tendancy to develop shorted paths where they were once "opened".
Does that mean that one could take a failed part and re-blast it with
the original program and return it to service?
-ethan
2:49 p.m.
On Thursday 15 June 2006 10:35 pm, Allison wrote:
It's bipolar and also programable (fuseable links) and they do have
a tendancy to develop shorted paths where they were once "opened".
Ah, I didn't know about that last bit...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Any idea as to why that should fail so often?
Thermal death? It's a bi-polar part, not *MOS, and it does run hotter
than the rest of the components. 
10:01 p.m.
[82S100 PLA]
It's bipolar and also programable (fuseable links)
and they do have
a tendancy to develop shorted paths where they were once "opened".
Yes, but why is it such a problem in the C64 (and SX64?) Is it just that
so many of those machines were sold that if only 0.1% of them fail it's
still a lot of dead chips? The 82S100 was used in a lot of other things
(including the PDP11/44 IIRC), and you don't hear about those failing all
the time.
-tony
6780
days inactive
6780
days old
3 comments
4 participants
participants (4)
-
ajp166＠bellatlantic.net -
ard＠p850ug1.demon.co.uk -
ethan.dicks＠gmail.com -
rtellason＠verizon.net