Re: S-100 resurrection in Australia
- From: s100fan <s100fan@xxxxxxxxx>
- Date: Tue, 31 Mar 2009 16:05:57 -0700 (PDT)
On Apr 1, 1:18 am, "John Crane" <jc email> wrote:
<snips>
Most chips can be replaced easily (Mouser, Digi-Key, etc.), others may
require a search among the antique chip dealers. The obvious exception is
ROM chips. If a ROM is dead, you will need to program another one as
finding a direct replacement is extremely rare. For this, you will need the
code that was in the ROM.
I have source code for the ROM, but not tools to program the chip.
<snips>
As far as caps go - tantalums die with age too but have low values. I'd
replace EVERY electrolytic and tantalum cap I find - especially if you
intend to actually use the machine, as opposed to a static display piece.
It's cheap insurance. Ceramics live longer and are usually ok. Sockets go
bad too and chip pins get corrosion/oxidation on them. DeoxIT (available at
Radio Shack) works for this. As far as chips themselves, it's usually the
buffers or inverters that go first. Resistors at the low voltages in
computers are reliable - but at high voltages (ham radio gear) they can
drift off spec over the years.
If I can isolate the already failed components by the methods you
suggest and get a working system, I'll then invest in the preventive
replacement of working caps.
The IMS was built for industrial environments and has very heavy power-
conditioning specs. My 16v and 8v power buses are running slightly
over voltage because local current is 240VAC and system is calibrated
for 220VAC. But card voltages after the voltage regulators all check
out <10% over spec which I understand should not be a problem.
Good luck and welcome to the S-100 world!
Thanks very much for your advice. Finding the necessary equipment, or
somebody within range of Canberra, Australia who has it, will be first
hurdle.
-John
.
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