29 Aug
2006
29 Aug
'06
4:53 p.m.
Hello All. I'm new to this list and would like some advice on learning the inner
workings of vintage computers. I have some basic experience with electronics and some
simple measurement tools (multimeter, logic probe). So far, I've repaired a couple of
older machines (Kaypro's, Compaq portables) but this has amounted to swapping dead
hard or floppy drives, replacing dead batteries, etc. So here are my questions: (1) Is
there a "trainer" system good for learning about microcomputer design and
operation, and (2) would an oscilloscope be useful for this purpose, and if so, what Mhz
rating is needed to work on older machines? I've noticed the price is directly
proportional to this number! Thanks, John R.
29 Aug
29 Aug
6:03 p.m.
Hello All. I'm new to this list and would like some advice on learning =
the inner workings of vintage computers. I have some basic experience =
with electronics and some simple measurement tools (multimeter, logic =
probe). So far, I've repaired a couple of older machines (Kaypro's, =
Compaq portables) but this has amounted to swapping dead hard or floppy =
drives, replacing dead batteries, etc. So here are my questions: (1) Is =
there a "trainer" system good for learning about microcomputer design =
There certainly _were_ Heathkit made at least one, so did (IIRC) HP. They
turn up on E-bay from time to time, but tend to go for what I consider to
be rather too much money.
What I would do in your position is get one of the simpler, but
well-known, 8 bit micros with few, if any, gate array chips (an Apple ][,
but not a //e, for example). And make sure a schematic is available.
Then, armed with test equipment, try to _really_ understand the design.
The first machine you do this for will take a long time. Later on you'll
be able to understand the schematic of a newly-obtained machine in a
couple of days.
Of course if you pick a machine that somebody else here knows about, you
can ask on the list questions like 'What the heck is NAND gate U24b for'.
and operation, and (2) would an oscilloscope be useful
for this purpose, =
and if so, what Mhz rating is needed to work on older machines? I've =
This is a personal thing. I don't use a 'scope much, prefering a logic
analyser, others prefer a 'scope.
But as I've said before, the most important piece of test equipment is a
brain. I've sorted out quite nasty logic faults using a multimeter, an
LED+resistor, and a lot of thought. But give the best logic analyser in
the world to somebody who doesn't know what they are doing, and it won't
help them at all.
To answer your second question, aim for a bandwidth ('MHz rating') of
about 3 times the fastest signal you want to look at (this may be the
master clock frequency). For most 8 bit micros, a 50MHz 'scope is fine.
And just as 'nobody ever got fired for buying IBM', you rarely go wrong
if you huy a Tektronix 'scope (no I don't work for them, I just like
their products).
-tony
30 Aug
30 Aug
8:35 a.m.
I couldn't agree more with Tony's recommendations. However if you can
find one for a reasonable price the Heathkit and HP 5036 trainers are
great. I praticularly like the HP if you can get all the manuals for it
since they also teach you how to use logic probes, logic analyzers, etc. Be
carefull buying older Tektronix scopes, the capacitors and switches go bad
in them with age and if they're not used regularly.
Joe
At 02:03 AM 8/30/06 +0100, Tony wrote:
Hello All. I'm new to this list and would like some advice on learning =
the inner workings of vintage computers. I have some basic experience =
with electronics and some simple measurement tools (multimeter, logic =
probe). So far, I've repaired a couple of older machines (Kaypro's, =
Compaq portables) but this has amounted to swapping dead hard or floppy =
drives, replacing dead batteries, etc. So here are my questions: (1) Is =
there a "trainer" system good for learning about microcomputer design =
There certainly _were_ Heathkit made at least one, so did (IIRC) HP. They
turn up on E-bay from time to time, but tend to go for what I consider to
be rather too much money.
What I would do in your position is get one of the simpler, but
well-known, 8 bit micros with few, if any, gate array chips (an Apple ][,
but not a //e, for example). And make sure a schematic is available.
Then, armed with test equipment, try to _really_ understand the design.
The first machine you do this for will take a long time. Later on you'll
be able to understand the schematic of a newly-obtained machine in a
couple of days.
Of course if you pick a machine that somebody else here knows about, you
can ask on the list questions like 'What the heck is NAND gate U24b for'.
and operation, and (2) would an oscilloscope be
useful for this purpose, =
and if so, what Mhz rating is needed to work on older machines? I've =
This is a personal thing. I don't use a 'scope much, prefering a logic
analyser, others prefer a 'scope.
But as I've said before, the most important piece of test equipment is a
brain. I've sorted out quite nasty logic faults using a multimeter, an
LED+resistor, and a lot of thought. But give the best logic analyser in
the world to somebody who doesn't know what they are doing, and it won't
help them at all.
To answer your second question, aim for a bandwidth ('MHz rating') of
about 3 times the fastest signal you want to look at (this may be the
master clock frequency). For most 8 bit micros, a 50MHz 'scope is fine.
And just as 'nobody ever got fired for buying IBM', you rarely go wrong
if you huy a Tektronix 'scope (no I don't work for them, I just like
their products).
-tony
2:46 p.m.
I couldn't agree more with Tony's recommendations. However if you can
find one for a reasonable price the Heathkit and HP 5036 trainers are
great. I praticularly like the HP if you can get all the manuals for it
I will admit to never having used either, but I've heard plenty of
recomendations from them.
My point was that you don't _need_ such a trainer. If you've got one, by
all means use it.
since they also teach you how to use logic probes,
logic analyzers, etc. Be
carefull buying older Tektronix scopes, the capacitors and switches go bad
in them with age and if they're not used regularly.
It's like many older things. They will need a bit (a lot?) of TLC to get
them back to rights.
But personally, I'd rather get an old Tektronix and spend a month
restoring it, knowing I've then got an instrument I can believe, than use
certain modern-ish 'scopes that never seem to give a believable trace.
Notice I said 'certain', there are pletny of (expensive) modern 'scopes
that I would trust.
-tony
6:47 p.m.
Hi Tony and Joe. Thanks for the advice! I found an expensive example ($450
and up) of the HP trainer on ebay, then found something similar made by a
company called EMAC (it even has the same 8085 processor). Not as
expensive, especially if you solder it yourself. I need the practice
anyway. Thanks again, John R.
----- Original Message -----
From: "Tony Duell" <ard at p850ug1.demon.co.uk>
To: <cctalk at classiccmp.org>
Sent: Wednesday, August 30, 2006 4:46 PM
Subject: Re: Need microprocessor trainer, oscilloscope advice?
I couldn't agree more with Tony's recommendations. However if you can
find one for a reasonable price the Heathkit and HP 5036 trainers are
great. I praticularly like the HP if you can get all the manuals for it
I will admit to never having used either, but I've heard plenty of
recomendations from them.
My point was that you don't _need_ such a trainer. If you've got one, by
all means use it.
since they also teach you how to use logic
probes, logic analyzers, etc.
Be
carefull buying older Tektronix scopes, the capacitors and switches go
bad
in them with age and if they're not used regularly.
It's like many older things. They will need a bit (a lot?) of TLC to get
them back to rights.
But personally, I'd rather get an old Tektronix and spend a month
restoring it, knowing I've then got an instrument I can believe, than use
certain modern-ish 'scopes that never seem to give a believable trace.
Notice I said 'certain', there are pletny of (expensive) modern 'scopes
that I would trust.
-tony 
2:03 p.m.
On Aug 29, 2006, at 7:53 PM, John D. Reeve wrote:
Hello All. I'm new to this list and would like
some advice on
learning the inner workings of vintage computers. I have some basic
experience with electronics and some simple measurement tools
(multimeter, logic probe). So far, I've repaired a couple of older
machines (Kaypro's, Compaq portables) but this has amounted to
swapping dead hard or floppy drives, replacing dead batteries, etc.
So here are my questions: (1) Is there a "trainer" system good for
learning about microcomputer design and operation, and (2) would an
oscilloscope be useful for this purpose, and if so, what Mhz rating is
needed to work on older machines? I've noticed the price is directly
proportional to this number! Thanks, John R.
Don't worry, you don't need much bandwidth for troubleshooting older
TTL logic...a 35MHz or 50MHz scope will do fine. I recommend a
Tektronix 453...They're small, cheap, reliable, and very capable.
Don't be fooled; it's a high-end professional oscilloscope, but it's
old...hence cheap. Like computers, they don't become less capable with
age, but unlike computers, we still do the exact same thing with
oscilloscopes now that we did 75 years ago...graph voltage against time
on a display. Today's 'scopes do things like FFTs and limit testing,
but 99% of most peoples' needs (whether they believe it or not) will be
met just fine with an old Tek 453 or 465.
You can probably pick a 453 up on eBay for less than $75. If you can
afford more than that, look for a Tektronix 465 or 475. (or 475A, etc)
Check out these URLs for very good info on the 453:
http://www.diyguitarist.com/TestEquipment/Tektronix453.htm
http://www.reprise.com/host/scopes/default.asp
I've had a 453 (still have it), a 475 (a friend has it now), and my
current Tek scopes are a 2465A and a TDS-3012. I also have an HP
54111D, but it hasn't seen much use since I got the TDS-3012.
For trainers...a Heathkit ET-3400 is small, cheap, and fun. HP made
a REALLY nice one built around the 8085, but they tend to be not so
cheap...I have a spare one that I'm about to put up on eBay.
-Dave
--
Dave McGuire
Cape Coral, FL
11 Sep
11 Sep
10:20 a.m.
Hello All. I'm new to this list and would like
some advice on learning the
inner workings of vintage computers. I have some basic
experience with
electronics and >some simple measurement tools (multimeter, logic probe).
So far, I've repaired a couple of older machines (Kaypro's, Compaq
portables) but this has amounted >to swapping dead hard or floppy drives,
replacing dead batteries, etc. So here are my questions: (1) Is there a
"trainer" system good for learning about >microcomputer design and
operation, and (2) would an oscilloscope be useful for this purpose, and if
so, what Mhz rating is needed to work on older machines? >I've noticed the
price is directly proportional to this number! Thanks, John R.
John,
The cheapest solution ( free !! ) I can think of is a Heathkit ET3400
emulator ! If you cannot find one online, contact me direct ( offlist ) and
I'll E-mail it to you. It's a pretty decent emulator. The graphics are okay.
This is for the 6800 microprocessor. It's a great teaching aid and the price
is right...
Best regards, Steven Canning
10:28 a.m.
I think the average price of a HP 5036 on eBay is about $80 to $100. I
have sold several over the last few years and never got over $110 for
one.
Paxton
Astoria, Oregon
USA
3:20 p.m.
Thanks for the advice guys. I've gotten hold of an oscilloscope and am
planning to plumb the depths of my collection of old computers. I haven't
fried anything yet... Cheers, John R.
----- Original Message -----
From: "Steven Canning" <cannings at earthlink.net>
To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
Sent: Monday, September 11, 2006 12:20 PM
Subject: Re: Need microprocessor trainer, oscilloscope advice?
Hello All. I'm new to this list and would
like some advice on learning
the
inner workings of vintage computers. I have some basic experience with
electronics and >some simple measurement tools (multimeter, logic probe).
So far, I've repaired a couple of older machines (Kaypro's, Compaq
portables) but this has amounted >to swapping dead hard or floppy drives,
replacing dead batteries, etc. So here are my questions: (1) Is there a
"trainer" system good for learning about >microcomputer design and
operation, and (2) would an oscilloscope be useful for this purpose, and
if
so, what Mhz rating is needed to work on older machines? >I've noticed
the
price is directly proportional to this number! Thanks, John R.
John,
The cheapest solution ( free !! ) I can think of is a Heathkit ET3400
emulator ! If you cannot find one online, contact me direct ( offlist )
and
I'll E-mail it to you. It's a pretty decent emulator. The graphics are
okay.
This is for the 6800 microprocessor. It's a great teaching aid and the
price
is right...
Best regards, Steven Canning
3:37 p.m.
The cheapest solution ( free !! ) I can think of is a Heathkit ET3400
emulator ! If you cannot find one online, contact me direct ( offlist ) and
I'll E-mail it to you. It's a pretty decent emulator. The graphics are okay.
This is for the 6800 microprocessor. It's a great teaching aid and the price
is right...
Maybe, but there is one heck of a difference between working on an
emulator and using (and modifying, interfacing, etc) the real hardware.
And the OP wants to learn about hardware, I believe.
-tony
4:23 p.m.
On 9/11/2006 at 11:37 PM ard at p850ug1.demon.co.uk wrote:
Maybe, but there is one heck of a difference between
working on an
emulator and using (and modifying, interfacing, etc) the real hardware.
And the OP wants to learn about hardware, I believe.
Why not start with a "mostly on one chip" type of setup, say a Z8 or 8051
and work from there? There are plenty of small circuits published using
them and, as the student's knowledge grows, other bits can be added on.
Perhaps one of the inexpensive boards from here might be a good start:
http://www.futurlec.com/DevelopmentBoards.shtml
Cheers,
Chuck
5:24 p.m.
Hi Guys. By the way, I've been working through the BASIC Stamp learning
modules. Is that what you have in mind? Lots of good information on simple
circuits and interfacing a microcontroller to various devices, but
surprisingly little about how the stamp actually does its magic. John R.
----- Original Message -----
From: "Chuck Guzis" <cclist at sydex.com>
To: <cctalk at classiccmp.org>
Sent: Monday, September 11, 2006 6:23 PM
Subject: Re: Need microprocessor trainer, oscilloscope advice?
On 9/11/2006 at 11:37 PM ard at p850ug1.demon.co.uk
wrote:
Maybe, but there is one heck of a difference
between working on an
emulator and using (and modifying, interfacing, etc) the real hardware.
And the OP wants to learn about hardware, I believe.
Why not start with a "mostly on one chip" type of setup, say a Z8 or 8051
and work from there? There are plenty of small circuits published using
them and, as the student's knowledge grows, other bits can be added on.
Perhaps one of the inexpensive boards from here might be a good start:
http://www.futurlec.com/DevelopmentBoards.shtml
Cheers,
Chuck
12 Sep
12 Sep
6:01 a.m.
On Sep 11, 2006, at 7:23 PM, Chuck Guzis wrote:
This is a good idea. One can put together, using wire-wrap or
point-to-point soldering, an 8752-based machine in an hour or two.
Five chips, only one of which is a 40-pinner. Burn a copy of the
well-known 8052AH-BASIC into it and you've got yourself quite a neat
little machine. The BASIC interpreter has excellent I/O capability,
interrupt support, and even floating-point math.
If anyone wants to do this but lacks the stuff, I have 8752 chips and
the means to program them. And the BASIC interpreter, of course.
-Dave
--
Dave McGuire
Cape Coral, FL
Maybe, but
there is one heck of a difference between working on an
emulator and using (and modifying, interfacing, etc) the real
hardware.
And the OP wants to learn about hardware, I believe.
Why not start with a "mostly on one chip" type of setup, say a Z8 or
8051
and work from there? There are plenty of small circuits published
using
them and, as the student's knowledge grows, other bits can be added on.
6447
days inactive
6461
days old
13 comments
8 participants
participants (8)
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