5 Jun
2006
5 Jun
'06
7:26 p.m.
Subject: Re: SBC6120 (a build-it-yourself PDP-8 clone) grammer checked
From: woodelf <bfranchuk at jetnet.ab.ca>
Date: Mon, 05 Jun 2006 14:46:33 -0600
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at
classiccmp.org>
I take it was tossup between a scope and good soldering iron
for the first best investment once you get off the kitchen table for
projects. The SBC6120 is good reason to get a better iron for me now.
A decent workbench with power and storage I number one in my book.
Lighting for it number two. Third is a good soldering iron. Around
number 7 is a 'scope after a decent pair of VOM and DVM and simple
logic probe. Number 6 is a quality set of handtools (cutters, needlenose,
screwdrivers and the like). If I were to think on it I'd certainly put
other tools and equipment before a scope.
PS. I notice most TTL projects are wire wrapped that I
have seen on the
web rather than having a PCB made.
Obvious reason. Rework in the form of circuit corrections are easily
done with wirewrap and can be costly and time consuming with PCB.
Allison
10 Jun
10 Jun
5:40 p.m.
A decent workbench with power and storage I number one
in my book.
Lighting for it number two. Third is a good soldering iron. Around
number 7 is a 'scope after a decent pair of VOM and DVM and simple
logic probe. Number 6 is a quality set of handtools (cutters, needlenose,
screwdrivers and the like). If I were to think on it I'd certainly put
other tools and equipment before a scope.
For electronic test instruments (not including hand tools, etc), my order
would be something like
1) A good VOM (analogue) or DMM, whichever type you prefer.
2) A logic probe
3) A bench power supply (at least 5A output)
4) The other of the VOM/DMM pair
5) A 'scope or logic analyser, depending on what sort of work you're doing
6) The other one of those instruments
7) Strange stuff that you get because you see it at a cheap price and it
looks interesting (curve tracers, valve testers, LCR bridge, etc)
PS. I notice most TTL projects are wire wrapped
that I have seen on the
web rather than having a PCB made.
Obvious reason. Rework in the form of circuit corrections are easily
done with wirewrap and can be costly and time consuming with PCB. 
13 Jun
13 Jun
8:22 p.m.
On Saturday 10 June 2006 05:40 pm, Tony Duell wrote:
I find it helps when prototyping to be able to build one bit of the
circuit, check it works properly, then add a bit more, and so on. This is
easy with wire wrap, harder on a PCB.
That was the way I learned how to build things as well, only we started with
a hunk of blank sheet metal and ended up with a 5-tube radio. :-)
--
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
For electronic test instruments (not including hand
tools, etc), my order
would be something like
1) A good VOM (analogue) or DMM, whichever type you prefer.
You need both! Though I do tend to reach for the digital stuff more often
than not, but that's more a matter of physical convenience than anything
else (little teeny DMM sits on my desk AAMOF).
2) A logic probe
I've not found those as useful as I'd have thought at one time. Got one here
that's "Continental Specialties" (?) or maybe later when they changed their
name to "Global Specialities" and I don't remember the last time I used it.
I even bought another one that Yamaha had out that produces an audible tone
as well. And I don't remember the last time I used it.
3) A bench power supply (at least 5A output)
5A at what voltage?
4) The other of the VOM/DMM pair
Yes.
5) A 'scope or logic analyser, depending on what
sort of work you're doing
6) The other one of those instruments
Scopes I've been using for ages, but never had occasion to use a logic
analyzer. Or could afford one.
7) Strange stuff that you get because you see it at a
cheap price and it
looks interesting (curve tracers, valve testers, LCR bridge, etc)
I'd love to get my hands on an LCR bridge, and am considering building one.
Got a curve tracer given to me some time back, and it's proved useful. And
built a tube tester from a kit, because that was the cheapest way to get one
at that time. Still works, too.
PS. I notice most TTL projects are wire wrapped that I
have seen on the
web rather than having a PCB made.
Obvious reason. Rework in the form of circuit corrections are easily
done with wirewrap and can be costly and time consuming with PCB. 
14 Jun
14 Jun
12:24 a.m.
On 6/13/2006 at 8:22 PM Roy J. Tellason wrote:
That was the way I learned how to build things as well,
only we started
with a hunk of blank sheet metal and ended up with a 5-tube radio. :-)
In my case, it was a piece of 3/4" thick pine board. If you didn't have
surface-mount sockets, you mounted the under-chassis type with spacers so
the lugs cleared the board for soldering. Back then, nice straight wires
taking right angle bends was a sign of careful construction. My father did
likewise in his day, only his wires weren't insulated and tended to be
around 14 AWG instead of my 18 AWG DCC wire.
Those were the days of real "breadboards".
Cheers,
Chuck
1:25 a.m.
On Wednesday 14 June 2006 12:24 am, Chuck Guzis wrote:
On 6/13/2006 at 8:22 PM Roy J. Tellason wrote:
Yes indeed, I've built a few things like that. Very short hunks of dowel at
the corners for "feet" so that screw heads wouldn't be dragging, and
fahnstock (sp?) clips for the connections "off-board". :-)
--
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
That was the way I learned how to build things as
well, only we started
with a hunk of blank sheet metal and ended up with a 5-tube radio. :-)
In my case, it was a piece of 3/4" thick pine board. If you didn't have
surface-mount sockets, you mounted the under-chassis type with spacers so
the lugs cleared the board for soldering. Back then, nice straight wires
taking right angle bends was a sign of careful construction. My father did
likewise in his day, only his wires weren't insulated and tended to be
around 14 AWG instead of my 18 AWG DCC wire.
Those were the days of real "breadboards". 
1:38 a.m.
New subject: (a build-it-yourself PDP-8 clone) NOT!
Roy J. Tellason wrote:
Yes indeed, I've built a few things like that. Very short hunks of dowel at
the corners for "feet" so that screw heads wouldn't be dragging, and
fahnstock (sp?) clips for the connections "off-board". :-)
Oddly most of the tubes and small parts you can find for still
bread-boarding a radio. It is only the transformers and coils
that are a pain to find as they say use ABC-123 coil for the broadcast
band and XYZ-987 for ... .
But if you like breadboard radios check out http://www.schmarder.com/radios/index.htm
and Dave's fine collection.
1:43 a.m.
New subject: (a build-it-yourself PDP-8 clone) NOT!
On Wednesday 14 June 2006 01:38 am, woodelf wrote:
Roy J. Tellason wrote:
Coils have *always* been a PITA for me, which is why I'm thinking lately of
building some kind of gadget to measure inductance, even if it's as simple
as a bridge or something...
Yes indeed, I've built a few things like
that. Very short hunks of
dowel at the corners for "feet" so that screw heads wouldn't be dragging,
and fahnstock (sp?) clips for the connections "off-board". :-)
Oddly most of the tubes and small parts you can find for still
bread-boarding a radio. It is only the transformers and coils
that are a pain to find as they say use ABC-123 coil for the broadcast
band and XYZ-987 for ... . But if you like breadboard radios check out
http://www.schmarder.com/radios/index.htm and Dave's fine collection.
I'll try and have a look tomorrow, as I'm fading fast here. :-)
--
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
9:30 a.m.
From: "Chuck Guzis" <cclist at
sydex.com>
On 6/13/2006 at 8:22 PM Roy J. Tellason wrote:
Hi
I did my first short wave receiver from an article in "Boys Life".
I use a piece of ply wood and borrowed a neighbors router
to make channels for all the wires and screws. It didn't
need the corner feet :)
Dwight
That was the way I learned how to build things as
well, only we started
with a hunk of blank sheet metal and ended up with a 5-tube radio. :-)
In my case, it was a piece of 3/4" thick pine board. If you didn't have
surface-mount sockets, you mounted the under-chassis type with spacers so
the lugs cleared the board for soldering. Back then, nice straight wires
taking right angle bends was a sign of careful construction. My father did
likewise in his day, only his wires weren't insulated and tended to be
around 14 AWG instead of my 18 AWG DCC wire.
Those were the days of real "breadboards".
Cheers,
Chuck
1:05 p.m.
On 6/14/2006 at 6:30 AM dwight elvey wrote:
I did my first short wave receiver from an article in
"Boys Life".
I use a piece of ply wood and borrowed a neighbors router
to make channels for all the wires and screws. It didn't
need the corner feet :)
When I was a boy, the local branch of the public library had an 1890's book
titled "Harper's Electrical Book for Boys" (IIRC). It showed how to make
everything from telephones to dynamos and lead-acid secondary cells and
carbon-arc lamps. It had directions that said things like "Go to a
blacksmith's shop and have him fabricate the following part" or "Oil of
Vitriol can often be obtained from your local illuminating gasworks."
I really liked that book, even though I never built anything from
it--blacksmiths were in short supply at the time--and I never did find my
local gasworks. I wonder if electronics will get to the point of some
young lad wondering where on earch one would find a 74LS00 or 2N2222 or
1N914 or even "hookup wire".
Cheers,
Chuck
5:16 p.m.
From: "Chuck Guzis" <cclist at
sydex.com>
----snip----
I really liked that book, even though I never built anything from
it--blacksmiths were in short supply at the time--and I never did find my
local gasworks. I wonder if electronics will get to the point of some
young lad wondering where on earch one would find a 74LS00 or 2N2222 or
1N914 or even "hookup wire".
We are already there. Even RS is not carrying simple parts any more.
Dwight
Cheers,
Chuck
7 p.m.
dwight elvey wrote:
We are already there. Even RS is not carrying simple
parts any more.
Dwight
I notice RS in Canada ( under a different name now ) has a lot of
switches and low voltage bulbs. Cell phones , clocks and computers
seem to the main items sold.
I have not seen a GOOD radio or reasionable Hi-Fi equipment in years.
PS. I am having a hard time finding hookup wire -- I am building a
tube/valve amp and nobody has wire that is for 600 volts DC that I like.
7:12 p.m.
woodelf wrote:
I have not seen a GOOD radio or reasionable Hi-Fi equipment in years.
PS. I am having a hard time finding hookup wire -- I am building a
tube/valve amp and nobody has wire that is for 600 volts DC that I like.
Gateway electronics in San Diego, Denver, or original in St. Louis has
a lot of wire. They will do mail order, though I usually go to the stores
rather than order, so can't vouch for their skill at taking orders. They
are a very old company, and I have known the founder and daughter
who runs it now for years, and they will make it right if there is a problem
and it needs solving.
Jim
9:42 p.m.
On 6/14/2006 at 6:30 AM dwight elvey wrote:
I have it (well, I would :-)). IIRC, the author worked for Edison for a
time.
I think it's beem reprinded by Lindsay Books (or at least was for a
time). So it may not be too hard to find.
I did my first short wave receiver from an article
in "Boys Life".
I use a piece of ply wood and borrowed a neighbors router
to make channels for all the wires and screws. It didn't
need the corner feet :)
When I was a boy, the local branch of the public library had an 1890's book
titled "Harper's Electrical Book for Boys" (IIRC). It showed how to make
everything from telephones to dynamos and lead-acid
secondary cells and
carbon-arc lamps. It had directions that said things like "Go to a
blacksmith's shop and have him fabricate the following part" or "Oil of
Vitriol can often be obtained from your local illuminating gasworks."
Some of the chemicals suggested for electorplating (and to a lesser
extent for batteries) were downright lethal!.
I really liked that book, even though I never built anything from
it--blacksmiths were in short supply at the time--and I never did find my
local gasworks. I wonder if electronics will get to the point of some
Well, 'Oil of Vitriol' is, IIRC, sulphuric acid, amd that is still not
too hard to get. And there are books on blacksmithing, so I guess you
could even do that part yourself if really determined! More seriously, a
lot of the metalwork described in 'Harpers electricing book for boys' can
be done mroe easiy with more moden tools (like an engineer's lathe for
screwcutting).
young lad wondering where on earch one would find a
74LS00 or 2N2222 or
1N914 or even "hookup wire".
I can easily imagine TTL disappering, but I think the TUPs and TUNs [1] (as
Elektor used to call them) will be availalbe.
[1] Transistor, Universal, PNP, Transistor Universal NPN. Basically,
generic trnasistors. Elektor used to publish circuits with trnasistors
labelled TUP and TUN (and diodes labelled DUG (germanium) and DUS
(silicon), along with quite long lists of components that would work in
all such positions.
-tony
15 Jun
15 Jun
1:14 p.m.
On Wednesday 14 June 2006 09:42 pm, Tony Duell wrote:
Well, 'Oil of Vitriol' is, IIRC, sulphuric
acid, amd that is still not
too hard to get.
Ah, interesting tidbit. I would imagine that it's available in places that
deal in batteries.
<...>
I can easily imagine TTL disappering, but I think the
TUPs and TUNs [1] (as
Elektor used to call them) will be availalbe.
[1] Transistor, Universal, PNP, Transistor Universal NPN. Basically,
generic trnasistors.
I've heard of them, I think it was on Tony van Roon's site, but have never
seen those referenced anywhere else.
Elektor used to publish circuits with trnasistors
labelled TUP and TUN (and
diodes labelled DUG (germanium) and DUS (silicon), along with quite long
lists of components that would work in all such positions.
Nice to know where that came from, I don't recall that bit being mentioned in
the original article I read but that wasn't any time recently.
A list such as that might be of some interest.
--
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
6:57 p.m.
[1]
Transistor, Universal, PNP, Transistor Universal NPN. Basically,
generic trnasistors.
I've heard of them, I think it was on Tony van Roon's site, but have never
seen those referenced anywhere else.
Elektor used to publish circuits with trnasistors
labelled TUP and TUN (and
diodes labelled DUG (germanium) and DUS (silicon), along with quite long
lists of components that would work in all such positions.
Nice to know where that came from, I don't recall that bit being mentioned in
the original article I read but that wasn't any time recently.
A list such as that might be of some interest.
11 p.m.
A list such as
that might be of some interest.
OK, I;ve found an old Elektor .
14 Jun
14 Jun
9:12 p.m.
On 6/13/2006 at 8:22 PM Roy J. Tellason wrote:
Have you (or anyone else) come across the 'Improverished Radio
Experimenter' books? THey're fairly modern (in the last 5 years or so),
and describe making valve receivers using this type of construction. The
valves go into those screw-terminal octal sockets normally used for
relays, coils, including the IF transformers are hand-wound on cardboard
tubes, etc). The result is a 3 valve superhet that takes up most of a
desk, but which apparently works.
-tony
That was the way I learned how to build things as
well, only we started
with a hunk of blank sheet metal and ended up with a 5-tube radio. :-)
In my case, it was a piece of 3/4" thick pine board. If you didn't have
surface-mount sockets, you mounted the under-chassis type with spacers so
11:05 p.m.
Tony Duell wrote:
Have you (or anyone else) come across the
'Improverished Radio
Experimenter' books? THey're fairly modern (in the last 5 years or so),
and describe making valve receivers using this type of construction. The
valves go into those screw-terminal octal sockets normally used for
relays, coils, including the IF transformers are hand-wound on cardboard
tubes, etc). The result is a 3 valve superhet that takes up most of a
desk, but which apparently works.
I seen a few mail order places selling them but I
want to get
"The Voice of the Crystal" -- build everything from scratch.
"Instruments of Amplification" -- build tubes/valves and transistors
from scratch.
I watch a lot of Japanese animation and they often having a si-fi
or alternate history setting have great "what if" inventions or
another version of common place things. If you like older space travel
the Japanese animated movie "The Royal Space Force:The wings of Honneamis"
is one to watch but it may be very hard to find.
15 Jun
15 Jun
6:34 p.m.
Tony Duell wrote:
> Have you (or anyone else) come across the 'Improverished Radio
> Experimenter' books? THey're fairly modern (in the last 5 years or so),
[...]
I seen a few mail order places selling them but I want
to get
"The Voice of the Crystal" -- build everything from scratch.
"Instruments of Amplification" -- build tubes/valves and transistors
from scratch.
I haev both, and love them.
'The voice of the Crystal' covers maing a crystal set using no commercial
electronic components (other than wire :-)). To be honset, this is the
less interesting of the 2 books, much of what's in it is in other books
too (although making a crystal earphone using the piezo-electric crystal
from a cigarette lighter is certainly novel.
'Instruments of Amplification' covers maing triode valves and copper
oxide transistors. Be warned this is not at all easy to do, and the
devices you make are pretty poor (lifetime of a few hours at most, gain
just over 1 if you're lucky!). Don't think you'll make a classic computer
using said devices. That said, it's amazing it's possible at all, and the
book is _well_ worth reading, if only to remind yourself than homebrewing
has not totlaly died out!
(You may have gathereed that I spend far too much on books!)
-tony
7:41 p.m.
Tony Duell wrote:
'Instruments of Amplification' covers maing
triode valves and copper
oxide transistors. Be warned this is not at all easy to do, and the
devices you make are pretty poor (lifetime of a few hours at most, gain
just over 1 if you're lucky!). Don't think you'll make a classic computer
using said devices. That said, it's amazing it's possible at all, and the
book is _well_ worth reading, if only to remind yourself than homebrewing
has not totlaly died out!
Heck I was thinking of Ne bulbs for a computer. :)
Well I guess it is time to admit I gave in to Modern Techolgy
and orderd a SBC6120.
I am deviving into older Valve stuff for my 6B4-G 3 watt channel
amp. Other than mostly improvements in speaker design and over all
better quality parts I don't see much difference in amplifer design
from the early 1960's with all the low end Single
Ended Triode stuff.
Most of the improvements on the real high end stuff seem to be
less cost cutting now that tubes are cheap and every thing else
is better priced. Still few people talk about regulated power and
screen supplys and correct Hi-Fi components compared to the stuff
from the 1940's.
16 Jun
16 Jun
5:53 p.m.
Heck I was thinking of Ne bulbs for a computer. :)
I seem to remember that Lindsay Books have reprinted at least one old
book on making neon signs :-)...
More seriously, there is a useful book called 'Cold Cathode Tube Circuit
Design' that contains circuits for using neon bulbs as counters and shift
registers. However, I don't think this book has been reprinted, and it's
not cheap second-hand (no, my copy is not for sale!)
-tony
7 p.m.
Tony Duell wrote:
Ok ... A neon bulb for 'One' and
'Zero' that flashes on and off.
Heck I was
thinking of Ne bulbs for a computer. :)
I seem to remember that Lindsay Books have reprinted at least one old
book on making neon signs :-)... More seriously, there is a useful book called
'Cold Cathode Tube Circuit
Design' that contains circuits for using neon bulbs as counters and shift
registers. However, I don't think this book has been reprinted, and it's
not cheap second-hand (no, my copy is not for sale!)
Since you got more books than
me, Do you have anything on the
frequency response of 0b2 voltage regulator with the standard .01 uf
bi-pass cap? I was hopeing to use a few in my latest amp?
-tony
.
7:07 p.m.
On Friday 16 June 2006 07:00 pm, woodelf wrote:
Tony Duell wrote:
Ok ... A neon bulb for 'One' and 'Zero' that flashes on and off.
I don't recall anything about the frequency response of those, but you might
find the datasheet helpful, which can be accessed at my tubes page, at:
http://www.classiccmp.org/rtellason/tubes.html
and I also happen to be downloading a bunch of related material from here:
http://www.electricstuff.co.uk/oldbooks.html
some of which might help...
--
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
Heck I was
thinking of Ne bulbs for a computer. :)
I seem to remember that Lindsay Books have reprinted at least one old
book on making neon signs :-)... More seriously, there is a useful book called
'Cold Cathode Tube Circuit
Design' that contains circuits for using neon bulbs as counters and shift
registers. However, I don't think this book has been reprinted, and it's
not cheap second-hand (no, my copy is not for sale!)
Since you got more books than me, Do you have anything on the
frequency response of 0b2 voltage regulator with the standard .01 uf
bi-pass cap? I was hopeing to use a few in my latest amp?
7:53 p.m.
On 6/16/2006 at 5:00 PM woodelf wrote:
Since you got more books than me, Do you have anything
on the
frequency response of 0b2 voltage regulator with the standard .01 uf
bi-pass cap? I was hopeing to use a few in my latest amp?
It's not above medium audio frequencies. (a few KHz at best).
The odd thing about gas-discharge tubes is that they work at all by sheer
probability.
If you can exclude all external and internal radiation (e.g. gamma
particles, light), a neon bulb won't fire at a voltage anywhere near its
spec-sheet level. The ionization avalanche needs an energetic particle or
photon to get it started. That's why neon bulbs fire at higher voltages in
a dark room than in a lit one. Manufacturers put a bit of radioactive
material (sometimes Krypton 85) in the gas mix to even things out. Very
old gas diodes tend to operate a bit more unpredictably than new ones
because a fair amount of the ionizing trigger material has decayed.
The curious upshot then, is that the time from the application of voltage
to the full ionization of a gas diode isn't consistent.
Cheers,
Chuck
10:37 p.m.
On Friday 16 June 2006 07:53 pm, Chuck Guzis wrote:
On 6/16/2006 at 5:00 PM woodelf wrote:
I find those parts interesting, anyhow. Which is why I've got myself an OC3
tube here, and some neons, to play with one of these days...
--
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
Since you got more books than me, Do you have
anything on the
frequency response of 0b2 voltage regulator with the standard .01 uf
bi-pass cap? I was hopeing to use a few in my latest amp?
It's not above medium audio frequencies. (a few KHz at best).
The odd thing about gas-discharge tubes is that they work at all by sheer
probability.
If you can exclude all external and internal radiation (e.g. gamma
particles, light), a neon bulb won't fire at a voltage anywhere near its
spec-sheet level. The ionization avalanche needs an energetic particle or
photon to get it started. That's why neon bulbs fire at higher voltages in
a dark room than in a lit one. Manufacturers put a bit of radioactive
material (sometimes Krypton 85) in the gas mix to even things out. Very
old gas diodes tend to operate a bit more unpredictably than new ones
because a fair amount of the ionizing trigger material has decayed.
The curious upshot then, is that the time from the application of voltage
to the full ionization of a gas diode isn't consistent.
17 Jun
17 Jun
6:03 p.m.
The odd thing about gas-discharge tubes is that they
work at all by sheer
probability.
If you can exclude all external and internal radiation (e.g. gamma
particles, light), a neon bulb won't fire at a voltage anywhere near its
spec-sheet level. The ionization avalanche needs an energetic particle or
Remidns me of the time I had a randomly flickering power-on neon on one
of the PSUs in my 11/45. As soon as I pulled the CPU out to get to it, it
stopped flickering. I thought 'Aha, a loose connection, shaken up by the
CPU fans when the CPU is in the rack', and started to invetigate. Nothing
wrong. I then discoveredm that even with the CPU in the rack, it would
stop filckering if I shone a torch (flashlight) on it. Hmmm....
photon to get it started. That's why neon bulbs
fire at higher voltages in
a dark room than in a lit one. Manufacturers put a bit of radioactive
I think one of the early computers (EDSAC?) used a matrix of neons and a
photomultipler as one of the ROMs. They had to 'flash' a light on the
matrix jut before each read (and gate out the resulting pulse from the PM
tube) to ensure a neon in the matrix would strike when required.
-tony
8:46 p.m.
On 6/17/2006 at 11:03 PM ard at p850ug1.demon.co.uk wrote:
I think one of the early computers (EDSAC?) used a
matrix of neons and a
photomultipler as one of the ROMs. They had to 'flash' a light on the
matrix jut before each read (and gate out the resulting pulse from the PM
tube) to ensure a neon in the matrix would strike when required.
I still have a neon "night light" in my shop that's just decrepit enough
that it comes on only during the daytime or when I turn the overhead lights
on. This avalanche effect of gas devices can come in very handy when used
for something like a PM tube.
(Point of curiosity: In British English, when is a tube a valve? You
fellows don't talk about "Cathode Ray Valves" do you? Is a photomultiplier
tube a "valve"? How about a TWT?)
Cheers,
Chuck
18 Jun
18 Jun
3:56 a.m.
Hi,
Chuck Guzis said:
(Point of curiosity: In British English, when is a tube a valve? You
fellows don't talk about "Cathode Ray Valves" do you? Is a
photomultiplier
tube a "valve"? How about a TWT?)
Photomultiplier tube and travelling wave tube is the norm over here in
my experience. The term "valve" is more of a function thing by analogy
with a valve controlling the flow of liquid, a thermionic valve is used
to control the flow of electrons. OK, so a crt controls the flow of
electrons, but it's primary funtion is to display the result, in fact you
could argue that a crt contains a valve :-)
--
Cheers,
Stan Barr stanb at dial.pipex.com
The future was never like this!
5:07 p.m.
my experience. The term "valve" is more of
a function thing by analogy
with a valve controlling the flow of liquid, a thermionic valve is used
I beleive the origin of the term 'valve' goes back to the diode, by
analogy with the one-way valve on a tyre or something like that.
-tony
19 Jun
19 Jun
3:45 a.m.
Hi,
Tony Duell said:
I seem to remember reading somewhere that Fleming introduced the term
around 1904 for exactly that reason.
--
Cheers,
Stan Barr stanb at dial.pipex.com
The future was never like this!
my experience.
The term "valve" is more of a function thing by analogy
with a valve controlling the flow of liquid, a thermionic valve is used
I beleive the origin of the term 'valve' goes back to the diode, by
analogy with the one-way valve on a tyre or something like that.
5:11 p.m.
I beleive the
origin of the term 'valve' goes back to the diode, by
analogy with the one-way valve on a tyre or something like that.
I seem to remember reading somewhere that Fleming introduced the term
around 1904 for exactly that reason.
18 Jun
18 Jun
5:04 p.m.
(Point of curiosity: In British English, when is a
tube a valve? You
fellows don't talk about "Cathode Ray Valves" do you? Is a photomultiplier
No, but there are many stories of uninformed customers telling the TV
enginere that the fault is the 'picture valve' :-)
tube a "valve"? How about a TWT?)
Hmmm. Good question. I am not sure of all cases, but we (the UK) would
talk about :
Diode valve, triode valve, tetrode valve, pentode valve, etc (up to
nonode valve), and things like 'frequency changer valve' (which is, I
think, what you'd call a 'converter tube').
But : Cathode ray tube, photomulitiplier tube, vidicon tube (and image
orthicon, iconoscope, if you go back that far), voltage stabiliser tube
(as in the gas-filled cold-cathode diode that started this thread :-)),
travelling wave tube, dekatron tube, nixie tube, trochotron tube, trigger
tube, etc
I think klystrons and magnetrons are more commonly 'valves' over here,
but 'tube' wouldn't sound too odd either.
Other terms change too. What you'd call a 'damper tube' in a TV
horizontal output stage, we'd call a 'booster diode (valve)' in a 'line
output stage'.
If anyone wants to know what I'd call a specific device, just ask.
-tony
6:16 p.m.
Tony Duell wrote:
Other terms change too. What you'd call a
'damper tube' in a TV
horizontal output stage, we'd call a 'booster diode (valve)' in a 'line
output stage'.
If anyone wants to know what I'd call a specific device, just ask.
^&%!$ As often as not I would guess. :)
-tony
6:21 p.m.
How about some of the more antique and exotics, such as "Crookes tube" or
"Geissler tube"?
How about the "Electron Ray Tube" aka "Tuning Eye Tube" (6E5, EM81,
etc.)?
Cheers,
Chuck
On 6/18/2006 at 10:04 PM ard at p850ug1.demon.co.uk wrote:
(Point of
curiosity: In British English, when is a tube a valve? You
fellows don't talk about "Cathode Ray Valves" do you? Is a
photomultiplier
No, but there are many stories of uninformed customers telling the TV
enginere that the fault is the 'picture valve' :-)
tube a "valve"? How about a TWT?)
Hmmm. Good question. I am not sure of all cases, but we (the UK) would
talk about :
Diode valve, triode valve, tetrode valve, pentode valve, etc (up to
nonode valve), and things like 'frequency changer valve' (which is, I
think, what you'd call a 'converter tube').
But : Cathode ray tube, photomulitiplier tube, vidicon tube (and image
orthicon, iconoscope, if you go back that far), voltage stabiliser tube
(as in the gas-filled cold-cathode diode that started this thread :-)),
travelling wave tube, dekatron tube, nixie tube, trochotron tube, trigger
tube, etc
I think klystrons and magnetrons are more commonly 'valves' over here,
but 'tube' wouldn't sound too odd either.
Other terms change too. What you'd call a 'damper tube' in a TV
horizontal output stage, we'd call a 'booster diode (valve)' in a 'line
output stage'.
If anyone wants to know what I'd call a specific device, just ask.
-tony
7:26 p.m.
How about some of the more antique and exotics, such as "Crookes tube" or
"Geissler tube"?
Yep, both of those asre 'tubes' in the UK
How about the "Electron Ray Tube" aka "Tuning Eye Tube" (6E5, EM81,
etc.)?
I think the official term is 'Electron Ray Tube' over here. The common
name is 'Magic Eye'.
-tony
16 Jun
16 Jun
7:14 p.m.
On 6/16/2006 at 10:53 PM ard at p850ug1.demon.co.uk wrote:
More seriously, there is a useful book called 'Cold
Cathode Tube Circuit
Design' that contains circuits for using neon bulbs as counters and shift
registers. However, I don't think this book has been reprinted, and it's
not cheap second-hand (no, my copy is not for sale!)
How about this one? Search engines are wonderful--my search term was "neon
multivibrator":
http://www.electricstuff.co.uk/oldbooks.html
Cheers,
Chuck
14 Jun
14 Jun
8:58 p.m.
On Saturday 10 June 2006 05:40 pm, Tony Duell wrote:
I would agree, but you can get away with only one when you're starting out.
For many years I used an analogue VOM only. To be honest, it's rare that
you need to make an accurate meashuremnt when repairing a classic
computer (you want to know if the 5V line is pressent and correct, but if
it's acutally 4.95V, things will still worl fine). Then I picked up a
cheap Fluke 85. I use that almost exclusively now, but the analogue meter
stays on my bench, it's better for osme things.
For electronic test instruments (not including
hand tools, etc), my order
would be something like
1) A good VOM (analogue) or DMM, whichever type you prefer.
You need both! Though I do tend to reach for the digital stuff more often than not, but that's more a matter of physical
convenience than anything
else (little teeny DMM sits on my desk AAMOF).
Tastes differ, I use one all the time. Actually, I've not used a normal
logic probe for the last 8 years or so, that's only because I bought a
LogicDart. But I debugged an awful lot of old computer stuff with a cheap
Radio Shack probe, and could do it again.
2) A logic probe
I've not found those as useful as I'd have thought at one time. Got one here
3) A bench
power supply (at least 5A output)
5A at what voltage? 4) The other of the VOM/DMM pair
Yes.
5) A 'scope or logic analyser, depending on
what sort of work you're doing
6) The other one of those instruments
Scopes I've been using for ages, but never had occasion to use a logic
analyzer. Or could afford one. I find it
helps when prototyping to be able to build one bit of the
circuit, check it works properly, then add a bit more, and so on. This is
easy with wire wrap, harder on a PCB.
That was the way I learned how to build things as well, only we started with
a hunk of blank sheet metal and ended up with a 5-tube radio. :-) 
10:57 p.m.
Tony Duell wrote:
(grin) Agreed. I've got a Fluke 8840A and it is really hard
to NOT wait for every digit on the display to settle down!
OTOH, if I pull out my Simpson 260P, the needle ballistics
are damped enough that you get a pretty quick "feel" for what
the number is.
I have an HP set (probe and pulser) and find them quite handy!
The biggest problem is making sure NOT to accidentally let it
touch some odd supply. :-(
Of course, it really works best with traditional TTL instead
of newer logic families (but, it's good enough to give you
a quick indication of "dead" lines, etc.
There are plenty of second-hand analyesers about that are fine for
classic computer repairs. I have an old Gould 100MHz unit.
As regards using it, it depends one what you work on, but I've found it
very useful for tracing microcode in some older machines. See what the
processor is really doing (and then work out if it should be doing it).
Problem with most logic analyzers is getting all the microhooks
(or easyhooks) that go with it. Without having to sell a kidney!
On Saturday 10
June 2006 05:40 pm, Tony Duell wrote:
I would agree, but you can get away with only one when you're starting out.
For many years I used an analogue VOM only. To be honest, it's rare that
you need to make an accurate meashuremnt when repairing a classic
computer (you want to know if the 5V line is pressent and correct, but if
it's acutally 4.95V, things will still worl fine). Then I picked up a
cheap Fluke 85. I use that almost exclusively now, but the analogue meter
stays on my bench, it's better for osme things. For electronic test instruments (not including
hand tools, etc), my order
would be something like
1) A good VOM (analogue) or DMM, whichever type you prefer.
You need both! Though
I do tend to reach for the digital stuff more often than not, but
that's more a matter of physical convenience than anything
else (little teeny DMM sits on my desk AAMOF).
Tastes differ, I use one all the time. Actually, I've not used a normal
logic probe for the last 8 years or so, that's only because I bought a
LogicDart. But I debugged an awful lot of old computer stuff with a cheap
Radio Shack probe, and could do it again. 2) A logic probe
I've not found those
as useful as I'd have thought at one time. Got one here 5) A 'scope or logic analyser, depending on what
sort of work you're doing
6) The other one of those instruments
Scopes I've been using for ages, but
never had occasion to use a logic
analyzer. Or could afford one.
11:07 p.m.
On Saturday 10 June 2006 05:40 pm, Tony Duell wrote:
For electronic test instruments (not including hand
tools, etc), my
order would be something like
1) A good VOM (analogue) or DMM,
If you're working much with analogue circuitry, particularly with
low-frequency events, it's still hard to beat a good old VTVM. Watching a
low-speed waveform go by with the meter needle set to center-zero just
can't be quite duplicated with digital displays. Reading resistances, on
the other hand, is very nice to do digitally.
I've still got my very old Mercury. Still works--old Reliable.
Cheers,
Chuck
15 Jun
15 Jun
6:25 p.m.
[Analogue .vs. ditial multimeter]
(grin) Agreed. I've got a Fluke 8840A and it is
really hard
to NOT wait for every digit on the display to settle down!
OTOH, if I pull out my Simpson 260P, the needle ballistics
are damped enough that you get a pretty quick "feel" for what
the number is.
Yep. Trying to get some voltate to maximum or minimum is a right pain
with a digital meter :-)
Oen other point. Most good digital meters are autoranging. Make sure you
can lock it on a particular range (or seleect the ranges manually, or
both). Habing it switch ranges and shift the desimal point halfway
through a measurement will drive you insane. As will waiting for it to go
from the highest resistance range to the lowest when
you're doing
continuity checks (think about it...)
>>> 2) A logic probe
[...]
Of course, it really works best with traditional TTL
instead
of newer logic families (but, it's good enough to give you
a quick indication of "dead" lines, etc.
One of the advantages of the LogicDart is that you have selectable
tresholds on the inputs. OK, all three channels have to be set to the
same threshold (it's actually quite rare that this causes a problem). The
insturemtn has pre-defined thresholds for TTL, 3.3V and 5V CMOS and ECL,
and you can also select your own (I used it to debug the -15V discrete
transistor logic in the HP9100, for example).
]...]
Problem with most logic analyzers is getting all the
microhooks
(or easyhooks) that go with it. Without having to sell a kidney!
Tell me about it. Unless you're insane (as I am), don't get a logic
analyser without the 'pods'. Making those is an interesting exercise in
high-speed analouge design. And only consider doing it if you know --
exactly -- the input spec of the main analyser unit
As regards the clips, I was lucky, Greenweld (back when they were in
Southampton) had some at a silly price (\pounds 1.00 for 10 or
something). I bought their entire stock [1] and passed them on to
friends, etc (no I don't have an more left, only the ones I need for my
own alanyser)
[1] I did the same thing when they had brand new, boxed, Emulex Q-bus
SCSI cards foe \pounds 10.00 each. I bought one, showed it to the system
manager wehre I was working (he was a serious DEC heed), and he basically
told me to go back the next day to buy the rest. I did. Again, I only
have a couple left for my own PDP11s....
-tony
8:51 p.m.
Tony Duell wrote:
Ah, cool! Mine are showing their age. Aside from CMOS and
HiNil, most stuff of it's vintage was different flavors of
TTL. I'd have to look at the schematics to see if the
thresholds are ratiometric or driven by real references.
[Analogue .vs. ditial multimeter]
Yup. This usually happens exactly *once* -- the first measurement
I make. Then, a suitable pejorative accomplishes the fix! :>
Meter has scales for .2K to 20M by decades (.2, 2, 20, 200, 2000,
20000) plus "auto". Also have to be careful to select 2 wire
vs. 4 wire measurements, etc.
(sigh) Too many buttons. And do I really *need* 5.5 digits?
(I think not! I don't keep it calibrated that often to
be able to use that much acuracy)
(grin) Agreed. I've got a Fluke 8840A and
it is really hard
to NOT wait for every digit on the display to settle down!
OTOH, if I pull out my Simpson 260P, the needle ballistics
are damped enough that you get a pretty quick "feel" for what
the number is.
Yep. Trying to get some voltate to maximum or minimum is a right pain
with a digital meter :-)
Oen other point. Most good digital meters are autoranging. Make sure you
can lock it on a particular range (or seleect the ranges manually, or
both). Habing it switch ranges and shift the desimal point halfway
through a measurement will drive you insane. As will waiting for it to go
from the highest resistance range to the lowest when you're doing
continuity checks (think about it...) >>> 2)
A logic probe
[...]
Of course, it really works best with traditional
TTL instead
of newer logic families (but, it's good enough to give you
a quick indication of "dead" lines, etc.
One of the advantages of the LogicDart is that you have selectable
tresholds on the inputs. OK, all three channels have to be set to the same threshold (it's actually quite rare that this
causes a problem). The
insturemtn has pre-defined thresholds for TTL, 3.3V and 5V CMOS and ECL,
and you can also select your own (I used it to debug the -15V discrete
transistor logic in the HP9100, for example).
]...]
I usually use mine with different CPU adapters. If I know I am
going to be doing something particularly "involved", I put
headers on the target and just run ribbon cables from the pods
to the target.
Problem with most logic analyzers is getting all
the microhooks
(or easyhooks) that go with it. Without having to sell a kidney!
Tell me about it. Unless you're insane (as I am), don't get a logic
analyser without the 'pods'. Making those is an interesting exercise in
high-speed analouge design. And only consider doing it if you know --
exactly -- the input spec of the main analyser unit As regards the clips, I was lucky, Greenweld (back
when they were in
Southampton) had some at a silly price (\pounds 1.00 for 10 or
something). I bought their entire stock [1] and passed them on to
friends, etc (no I don't have an more left, only the ones I need for my
own alanyser)
Yeah, I saw some micro grabbers here at 50c/each but decided that
buying 200 of them was ridiculous!
[1] I did the same thing when they had brand new,
boxed, Emulex Q-bus
SCSI cards foe \pounds 10.00 each. I bought one, showed it to the system
manager wehre I was working (he was a serious DEC heed), and he basically
told me to go back the next day to buy the rest. I did. Again, I only
have a couple left for my own PDP11s....
<grin> I did that with chrome audio cassettes... bought 2000 of
them in one lot. Amazing how much space 2000 cassettes take up!
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