6 Jun
2006
6 Jun
'06
3:22 p.m.
That goes back a ways! I don't remember the name of the machine, but it was a
patented process by IIRC PhotoCircuits based in NY. I had the opportunity to see
one of the machines run at one of their plants while working on another machine,
and it was pretty impressive. I'm not sure it was a cost effective solution for
double sided PCBs, but back then, it was certainly an alternative for multilayer
boards.
From: Brent Hilpert <hilpert at cs.ubc.ca>
There was another technique for making circuit boards
in the 70s: a
programmed/automated machine moved over the initially bare board and laid down
a fine wire from a spool to form the circuits. I think the wire stuck to the
board initially and the board was later lacquered or coated with something to
seal/hold the wires better. I forgot how the wire traces were terminated
around IC pin locations, probably a pressure weld.
I think the economics were such that it was too slow for large production
runs, but was suitable for prototypes and small production runs of larger,
more-complex boards. Last example I saw was a disk-controller for a TI-990
mini circa 1980.
Anybody remember the name for the technique?
6 Jun
6 Jun
4:07 p.m.
New subject: PCB vs wirewrap, was Re: SBC6120 (a build-it-yourself PDP-8
DWT was still actively discussed as late as 5 years ago. DWT has two
distinct advantages over traditional PCB. One of which is shorter
interconnect length; the other is lower crosstalk. I think it's declined
only because of the relatively slow production process and the gradual
phase-out of through-hole component mounting.
Several years before the 8080 debuted, I set about building my own
computer, severely under-estimating what it was going to take in terms of
time, etc. At the time, DIP was very new, so most ICs were packaged in
TO-100 cans or flatpacks. Rather than resort to fulll PCB with a
technology that I was unfamiliar with, I etched a single-sided PCB with
pads for both types of ICs and interconnected them with #24 enameled magnet
wire. I got as far as building a working 8-bit ALU with 2 registers, but
lost interest when I realized I didn't have a good solution for memory.
For a time, I toyed with getting a drum (used on aircraft, I think) from
Meshna, but never got around to it. By that time, the 8008 had made its
appearance and I was trying to figure out the best way to build a system
based on that chip. I wound up with a MITS 8800 evenually.
Cheers,
Chuck
8:07 p.m.
New subject: PCB vs wirewrap, was Re: SBC6120 (a build-it-yourself
technology that I was unfamiliar with, I etched a
single-sided PCB with
pads for both types of ICs and interconnected them with #24 enameled magnet
wire. I got as far as building a working 8-bit ALU with 2 registers, but
Over here there were wiring systems solder under the brand names of
'Verowire' and 'Road Runner'. You had a 'pen' which contained a
spool of
enammeled copper wire, the enammel was designed to melt at soldering
temperatures. You soldered the ICs/sockets/etc onto square pad board, and
rand the wire between the pins. soldering as you go.
The verowire tool was much nicer as it had a metal tip. The road runner
tool tended to melt if you weren't careful.
It was not really suiable for production (far too slow, and not
mechancially robust), but it worked well for prototyping (up to at least
FAST speeds if you used a ground plane board). I've built a lot of stuff
using it.
-tony
8:59 p.m.
New subject: PCB vs wirewrap, was Re: SBC6120 (a build-it-yourself
On 6/7/2006 at 1:07 AM ard at p850ug1.demon.co.uk wrote:
Over here there were wiring systems solder under the
brand names of
'Verowire' and 'Road Runner'. You had a 'pen' which contained a
spool of
enammeled copper wire, the enammel was designed to melt at soldering
temperatures. You soldered the ICs/sockets/etc onto square pad board, and
rand the wire between the pins. soldering as you go.
The verowire tool was much nicer as it had a metal tip. The road runner
tool tended to melt if you weren't careful.
I think that Vector briefly offered a similar system here. I don't recall
the name.
IIRC, this preceded the Strip-n-Wrap system that was offered with a tool
that cut small slits in the very thin insulated wire, so that it would
contact the corners of a square wirewrap post. This (ostensibly) was
wonderful because you could daisy-chain your wraps without cutting the
wire. It never worked that well for me--the connections weren't really
tight, the wire was expensive, and the insulation was very very thin.
Cheers,
Chuck
10:10 p.m.
New subject: Temperature Compensated Crystal Oscillators
Seems my luck in getting all mypackages to my house intact has ended. I
managed to snag a complete Media 100 video capture board setup for my old
Macs and the person who packaged it didn't do such a good job. I found a few
tantalum capacitors laying in the ESD bag, and on close inspection found
another 4-5 that were lose. I soldered the caps back where they should have
been and then noticed that one of the crystal oscillator had pins broken off
inside the device, plus there is a small brownish surface mount cap missing
next to the oscillator that I could not find.
So I wonder if that small cap is needed for the card to run, and where am I
going to find a new Crystal oscillator to replace the one that is broken.
Anybody happen to have a K1602 T laying around they don't need?
http://www.brookdale.com/champion/k1601.htm shows the part in question. The
frequency needed is 24.545454 Mhz.
P.S how do you read any marking on a tiny surface mount capacitor? My cheapo
magnifying glass didn't show anything, I even tried using a scanner at 1200
DPI and got nothing but a blur. At first I thaught it was a resistor but
the part number C238 I believe must be a capacitor.
Thanks for any help, I would rather get this unit working then have to toss
it (kind of rare) just because of a couple parts.
10:31 p.m.
New subject: Temperature Compensated Crystal Oscillators
On 6/6/2006 at 10:10 PM Teo Zenios wrote:
P.S how do you read any marking on a tiny surface mount
capacitor? My
cheapo
magnifying glass didn't show anything, I even tried using a scanner at
1200
DPI and got nothing but a blur. At first I thaught it
was a resistor but
the part number C238 I believe must be a capacitor.
Get a compound loupe--fairly inexpensive and absolutely indispensible.
10:49 p.m.
New subject: Temperature Compensated Crystal Oscillators
A loupe rarely helps for surface mount caps because surface mount
caps don't have markings. Very annoying. Most electrolytics do, either
in 'A' case style (and up), or the cans. I also have a number of 2512
and one size larger that have no markings. Only way to tell is with a
capacitance meter. And if you're dealing in picofarad range caps in RF
circuits and such, it doesn't help either, unless it's very very expensive.
--jc
Chuck Guzis wrote:
On 6/6/2006 at 10:10 PM Teo Zenios wrote:
P.S how do you read any marking on a tiny surface
mount capacitor? My
cheapo
magnifying glass didn't show anything, I even tried using a scanner at
1200
DPI and got nothing but a blur. At first I
thaught it was a resistor but
the part number C238 I believe must be a capacitor.
Get a compound loupe--fairly inexpensive and absolutely indispensible.
7 Jun
7 Jun
2:58 a.m.
New subject: Temperature Compensated Crystal Oscillators
On 6/6/2006 at 10:10 PM Teo Zenios wrote:
plus there is a small brownish surface mount cap
missing
next to the oscillator that I could not find.
So I wonder if that small cap is needed for the card to
run, and where am
I
going to find a new Crystal oscillator to replace the
one that is broken.
Check to see if the capacitor is connected between ground and +5. If so,
it's just a decoupling capacitor and just about any value between .01 and
.1 uF will do the job.
http://www.brookdale.com/champion/k1601.htm shows the
part in question.
The
frequency needed is 24.545454 Mhz.
You might check with Alltronics. They claim to have the frequency in stock
for $4.00:
http://www.alltronics.com/cgi-bin/email.cgi?item=OSC_24_545454&category…
I don't know if it's the right package or if it has a trimmer, but it's a
start.
Cheers,
Chuck
P.S how do you read any marking on a tiny surface mount capacitor? My
cheapo
magnifying glass didn't show anything, I even tried using a scanner at
1200
DPI and got nothing but a blur. At first I thaught it
was a resistor but
the part number C238 I believe must be a capacitor.
Thanks for any help, I would rather get this unit working then have to
toss
it (kind of rare) just because of a couple parts.
6594
days inactive
6595
days old
7 comments
5 participants
participants (5)
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