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Micom 2000
June 8th, 2009, 07:55 PM
The Tools section hasn't had a post for over a month. The thread in the forsale section had an interesting thread on a Heathkit VTVM which expanded to oscilloscopes and other things.
Common was the view that one of the Monitors would move it to "off-topic", but eager to talk about it. I hesitated about mentioning my old Dumont Scope from the mid-fifties as well as many other ancient electronic "Tools" such as frequency generators or an old "Decade" box. A google found that even the Computer History Museum has a Dumont scope in it's collection. Surely vintage or otherwise, "Tools" isn't limited to soldering irons or Tork screwdrivers. It's about electronics. Scopes, VTVMs, and continuity testers are all part of many collectors tools. Even Tubes (Valves) enter into it.

Tools could be a very interesting section if it opened up. Had the Heathkit thread been transferred here it would have likely be still continuing. Perhaps with this thread it can be.

What tools do you have for testing and repairing computers ? Some of the stuff Tezzi does with his computer tools amazes me as well as what many other posters efforts do.

Lawrence

Unknown_K
June 8th, 2009, 08:01 PM
Simple tools: POST card, fluke multimeter, soldering/desoldering irons, security screwdrivers.

Would be nice to have a scope but for the things I collect even if you found a faulty chip you would need to grab a new one from a working board anyway (outside or RAM).

Druid6900
June 8th, 2009, 08:09 PM
Logic probe, signal injector, parallel port 2 channel O'scope, POST card, curve tracer, DMM, soldering iron, 3rd hand, snort-type solder extractor, various hand tools.

I think that about covers my main day-to-day tools.

Lou - N2MIY
June 9th, 2009, 04:09 PM
Electrical tools I find most helpful (in order) are:

DMM
Scope (here's mine: http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=65)
Logic Analyzer (http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=210)
Solder Sucker (the RadioShack desoldering iron - new tips are cheap, so if it's a four layer board with fine traces, that job deserves a new tip!)
Pencil iron with sharp tip (how many of us know the tricks to tin a new or recently sharpened tip?)
Card extender (for bringing dec modules up and out of backplanes so they can be probed)
EPROM programmer
Frequency counter
Small shortwave radio (tune it to the frequency of the oscillator you want to check before hauling test equipment out)

I totally understand the value of a meter with a D'Arsonval movement, but I tend to use the scope when a fast response is required.


And the "mechanical" tools:

Good wire strippers
Good small diagonal cutters
Good fine needlenose pliers
DIP Clips (maybe that's electrical? - Gotta have 14 pin through 40 pin)
Finger (we have 10, for feeling for overheated devices)
Wire wrap tool
Fine pick (for poking, prying)
Magnifying glass
Really bright desk lamp
Single edge razor blades (scraping, cutting, etc.)
Wet sponge for cleaning the iron tips


"Software" tools

Floppy Machine (http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=3) with Imagedisk and PUTR



Lou

Chuck(G)
June 9th, 2009, 05:21 PM
In order

A piece or two of wire
DMM
Logic Probe
Scope
Pillow
Odds and ends from my hellbox
Logic Analyzer

As exotic as it is, a logic analyzer is rarely useful in repairs. By the time I get to the scope, I'm relying more on the logic analyzer in my head and find it more useful just to sleep on the problem rather than going through the bother of setting the analyzer up.

tezza
June 9th, 2009, 05:50 PM
Apart from the obvious (soldering iron, wick, screwdrivers etc.) mostly just a $20 digital multimeter.

However, I have had assistance from pavery's scope, on the Pet project and Kaypro drive fix. I used it for some of the later repairs to other things but essentially just to show voltage. The multimeter would have been ok for this too.

Oh, and to check if there was any AC ripple in the DC output from the Osborne 1 PSU (there wasn't).

I think the only fix I've done which would have been impossible without the scope was the Kaypro drive (with the Pet, the whole board was replaced in the end). All the rest of the repairs were largely a matter of multimeter voltage testing, deduction and good luck! (a fair amount of the latter I suspect).

Tez

Micom 2000
June 9th, 2009, 08:40 PM
Of course as a computer professional you would have the gamut of devices.

Logic probe: I have one which I constructed as part of my digital computer course. We were then instructed how to use it and to find faults on chips mounted on the ET3400 trainer or a circuit board. I was delighted to find a faulty flip-flop. It was pretty primitive.
IIRC the H-P one was the cadillac of probes. What's yours ?

Signal injector: Obviously needed if you wanted an output.

PP Scope: Is this one of the CPU-based scopes obviating the need for a scope with a CRT ?

POST Card: Excellent tool for when everything on the computer seems dead. Just bought one of the chinese offerings but haven't tried it yet.

Curve Tracer: What is it for ?

DMM(digital multimeter (?): Essential. I have an old analogue B+K as well a some pocket analogue and digital VMs

Soldering guns: Best are the temperature select ones and for other uses, different sized tips. Also a solder sucker for when unsoldering.

3rd hand: I have an old one which also on one of it's arms has a magnifying glass. Definitely makes some jobs easier.

Also handy at times are the bare circuit-board plug-ins. I even have a fondness for my ancient Decade box for adding different resistance values. More for audio are the Frequency generators and Tube-testers.

One of my frustrations is the virtual indecipherability of the manufacturers labelling of memory cards. Other than installing them in a computer are there any ways of determining their values ? Altho you can usually read the speed and value of chips some are also indeciperable.

Lawrence


Logic probe, signal injector, parallel port 2 channel O'scope, POST card, curve tracer, DMM, soldering iron, 3rd hand, snort-type solder extractor, various hand tools.
I think that about covers my main day-to-day tools.

channelmaniac
June 9th, 2009, 09:51 PM
By far and away I use the DMMs and Logic Probes the most.

Beyond that I have:

Dual Trace Oscilloscope
ESR cap meter
Function Generator
Logic pulser
CRT tester/rejuvenator
Frequency Counter
Computer Monitor Signal Generator (TTL/Analog, standard through XVGA resolutions)
Crystal tester
3 different EPROM programmers (one REAL old one for doing ancient chips)
Soldering/desoldering stations

And, The Internet. Useful for finding schematics or chip data sheets. (http://www.datasheetarchive.com)

RJ

cosam
June 10th, 2009, 12:29 AM
I love my tools, but for years I got by with little more than a $10 multimeter, el-cheapo soldering iron and basic hand tools. Various screwdrivers, needle-nosed pliers, side cutters, tweezers, an X-acto knife and the like are still very high on my most useful list, even if most have since been replaced with better quality versions. I think "roughing it" like that really makes one appreciate good tools and how much easier everything is when you actually have the correct equipment for the job at hand. All these things seem to become indispensable very quickly when you get used to having them and you really wonder how you ever got along without them.

Getting an oscilloscope really opened a lot of doors for me. Using a Fluke 115 after messing around with a cheap multimeter was quite an eye-opener too. Next on the list will probably be a proper soldering station. I think I may be developing a tool-collecting problem in order to feed my terrible vintage computer habit ;-)

Druid6900
June 10th, 2009, 06:48 PM
Of course as a computer professional you would have the gamut of devices.

Logic probe: I have one which I constructed as part of my digital computer course. We were then instructed how to use it and to find faults on chips mounted on the ET3400 trainer or a circuit board. I was delighted to find a faulty flip-flop. It was pretty primitive.
IIRC the H-P one was the cadillac of probes. What's yours ?

Both the logic probe and signal injector (logic pulser) are B&K and I got it as a kit with a clip-on chip monitor (the ones with an LED for each pin) and a couple of plain chip clips for attaching the various and sundry leads that came with the kit and replace the probe point.


Signal injector: Obviously needed if you wanted an output.

As mentioned above. I call it a signal injector because it can generate several different types of signals.


PP Scope: Is this one of the CPU-based scopes obviating the need for a scope with a CRT ?

Yup, it is. I just hook it up to a thinkpad's parallel port and I have a scope I can actually SEE LOL. Comes in a 4 channel version as well.


POST Card: Excellent tool for when everything on the computer seems dead. Just bought one of the chinese offerings but haven't tried it yet.

I use the POST cards a lot as the stuff I usually get, I get because it isn't working.


Curve Tracer: What is it for ?

It's a box I built a long while back that allows testing ICs, transistors and passive components in-circuit when hooked up to a dual trace scope (like the PP one I have) with X/Y capabilities and (after you get used to what the various curves are supposed to look like) allow you to run down the pins of ICs on a board and find open/short/leaky gates/components.


DMM(digital multimeter (?): Essential. I have an old analogue B+K as well a some pocket analogue and digital VMs.

I don't use this a whole lot, mostly for rough voltage measurements and testing diodes when the curve tracer is somewhere else in the house LOL.[/QUOTE]


Soldering guns: Best are the temperature select ones and for other uses, different sized tips. Also a solder sucker for when unsoldering..

Can't do much in the way of repair without a least one each of these :)


3rd hand: I have an old one which also on one of it's arms has a magnifying glass. Definitely makes some jobs easier.

Yes, mine is the one with the two sliding, articulated arms and the high-powered magnifying in the middle. Mandatory after a certain age :)


Also handy at times are the bare circuit-board plug-ins. I even have a fondness for my ancient Decade box for adding different resistance values. More for audio are the Frequency generators and Tube-testers.

One of my frustrations is the virtual indecipherability of the manufacturers labelling of memory cards. Other than installing them in a computer are there any ways of determining their values ? Altho you can usually read the speed and value of chips some are also indeciperable.

Lawrence

ziloo
June 10th, 2009, 09:48 PM
.....Yup, it is. I just hook it up to a thinkpad's parallel port and
I have a scope I can actually SEE LOL. Comes in a 4 channel
version as well....

Hello Druid,

1- Is the performance comparable/better/lower than a standard scope?

2- Would you please answer the following question (if possible) regarding
the OScope probe?

http://www.vintage-computer.com/vcforum/showthread.php?t=15744&page=3


Thank you

ziloo

Druid6900
June 11th, 2009, 08:12 PM
Hello Druid,

1- Is the performance comparable/better/lower than a standard scope?

2- Would you please answer the following question (if possible) regarding
the OScope probe?

http://www.vintage-computer.com/vcforum/showthread.php?t=15744&page=3


Thank you

ziloo

Much lower, I think it's about 4MHz bandwidth, but considering you don't need probes and I mostly use it to drive my curve tracer, it's not a problem.

I rarely use a scope to fix anything, in fact, I probably use my TTL/CMOS/DIP DRAM chip tester ten times as much.

As for the probes, yes, they should be matched to the bandwidth (or exceed it) and I used to "tune" the probes using the built in reference output every time I used it (yours may not have one).

In fact, even when I was with Tandy, the only time I ever used a scope was when I was doing the old analogue alignment on a floppy drive or the old hard drive controller boards.

carangil
June 12th, 2009, 01:06 PM
At my previous job, I had to debug and service some legacy digital logic circuits, which is similar to repairing an old computer. A lot of our stuff had no CPU.


Digital sampling oscilloscope
Logic probe
Frequency counter
Multimeter


Very basic tools. I was debugging a synchronous serial bus, so I had one scope channel on clock, and the second channel on the bitstream. I only had 2 channels,so I used a resistor divider so the Tx and Rx lines were different voltage weights. Then the fun came when I had to decode the packet by hand!

That job was really fun.

dave_m
June 15th, 2009, 02:08 PM
I hesitated about mentioning my old Dumont Scope from the mid-fifties as well as many other ancient electronic "Tools" such as frequency generators or an old "Decade" box.


Wow, you have a Dumont. I have heard of them but have never seen one. Could you post a picture of it?

Here is a picture of my oldest piece of test equipment, a Hewlett Packard Model 5240A Digital Frequency Meter. It is an old counter that used Nixie tube displays. When I started in the electronics industry in 1969, a lot of the test equipment like counters and voltage meters had Nixie displays. I was always fond of them. The counter is hooked up to the calibrator signal (1KHz) from a scope. The second photo shows a closeup of the numerical filaments.

1790

1791

Micom 2000
June 18th, 2009, 08:08 PM
I thought I had some pics of my Model 340 but I couldn't find them. I also have the schematics for it. The last time I worked on it, over 10 years ago, the Y trace didn't work because a "neon" (resistor?) was blown. I doubt if they're even available any more. But the round little CRT lit up. One thing I noticed was the tubes were mainly all audio tubes like one can find in older hi-end tube amps.

I found some Google images of Dumonts, but not my particular model. At some point I'll have to dig it out and take some pics. Also copy the schematics.

Lawrence

Druid6900
June 19th, 2009, 07:13 PM
You know what I could really use for my test gear collection?

A tilt/swivel base for my Taxan Multivision 770+ monitor :)

Dwight Elvey
June 20th, 2009, 05:59 AM
Hi
If I had to pick tools that I felt were important to
fixing old computers it might be in this order:

100MHz Scope with delayed trace
( really a powerful way to analyse complex actions )
EPROM programmer
( not just to replace dead firmware but as a debugging tool.
I often write simple debug code and blow an EPROM. It
is a much easier way to check a board full of RAM that
is soldered in. One just writes a bit of test code. You get
the idea )
Analog volt meter ( not VTVM or FET input but just normal )
Soldering Iron ( Obvious uses )
Solder Sucker ( couldn't live without this one )
Bits and Pieces of wire ( can't always probe working devise without this )
Normal hand tools ( pliers, screw drivers, cutters, strippers etc )
Dwight

ziloo
June 20th, 2009, 08:02 AM
Hi
....100MHz Scope with delayed trace
( really a powerful way to analyse complex actions )


Hello Dwight,

Would you please explain how the delayed trace works and
how you use it to analyze complex events?

Thank you

ziloo

Micom 2000
June 20th, 2009, 02:13 PM
Great site. Thanks. But I still can't toss my old Electrosonics catalogues. :^)

Lawrence


And, The Internet. Useful for finding schematics or chip data sheets. (http://www.datasheetarchive.com)

RJ

Micom 2000
June 20th, 2009, 02:29 PM
Many years ago I removed most of the swivel bases from my monitors, so they would fit in my shelving. So now on my top shelves I have a S--t-load of bases none of which have any markings as to which monitor they belong to. Doh. :^{ It's entirely possible I have it. Identifying it is another problem. Usually when I want a base for a current monitor I haul them down and go thru a process of elimination. Of course some of the monitors never came with a base, and other bases are orphans from a discarded or left behind monitor. Mea Culpa.

Lawrence


You know what I could really use for my test gear collection?

A tilt/swivel base for my Taxan Multivision 770+ monitor :)

Micom 2000
June 20th, 2009, 03:03 PM
Now that I have a POST card my next most desired piece of equipment for over 2 decades was an EPROM burner. Could never afford one. I even need one to be able to burn some chips for a couple of Grid 1520 LTs. Grid in it's wisdom only allowed 3 models of small capacity Conner HDs, and of course they have usually failed in most Grids over the years, as mine has. One of the guys on the Yahoo Grid forum came up with a BIOS code to overcome the problem, but of course that demands an EPROM burner. The Grids also had 2 vacant(in mine) sockets in which you could put a boot OS or sequence which preceded the OS boot-search. Many put the Grid-Dos or MSDOS there, or of course anything else you wanted.

The 1520 was an AT, but had 8 SIPP sockets, allowing 8megs of memory. Up until my HDs failed, I could run Win 3 on them. Another item on a much too overlong "to-do" list. :^(

Lawrence

Druid6900
June 20th, 2009, 07:54 PM
Many years ago I removed most of the swivel bases from my monitors, so they would fit in my shelving. So now on my top shelves I have a S--t-load of bases none of which have any markings as to which monitor they belong to. Doh. :^{ It's entirely possible I have it. Identifying it is another problem. Usually when I want a base for a current monitor I haul them down and go thru a process of elimination. Of course some of the monitors never came with a base, and other bases are orphans from a discarded or left behind monitor. Mea Culpa.

Lawrence

Yes, I can understand that, L, but you're the one that asked me if you had shipped the base with the monitor because you found one where the Taxan used to be sitting LOL

Dwight Elvey
June 21st, 2009, 04:56 AM
Hello Dwight,

Would you please explain how the delayed trace works and
how you use it to analyze complex events?

Thank you

ziloo

Hi
Lets say you were trying to decode a new disk format. You
need to gat a sample of the bit stream right at the start
of the header. The problem is there may be several sectors
starting but you really only want to see the first sector on
the track. You need to sync the scope on the index pulse
but the data doesn't start for 200 us after the index and
you want to see only 10 or so 1 us pulses on the screen
at a time.
You can't do this on a scope without delayed trace.
Another example is that you've been watching to
see where in a ROM sequence the code gets lost. You
know it is someplace in the first 1K someplace. You
set your sync on a repeated reset you get from the
scopes self trigger. You scan across, watching the
CE signal to the ROM until you find where it got lost.
Stepping back one CE at a time, you find the instruction
that caused all the troubles.
I've done both of these with my scope.
Dwight

ziloo
June 21st, 2009, 05:58 AM
Great explanation Dwight...thank you!
And another thanks to Druid :).

ziloo

Micom 2000
June 22nd, 2009, 12:28 PM
Actually I was talking about a rubber inset on the base of the monitor. If you have an idea for identifying the tilt-base I could search thru the ones I have. Embarassingly, as a certified Atari ST freak, with about 5 ST monitors I can't find one that fits. I can't believe that of all these monitors I acquired there isn't one. Similarly for about 7 treasured 17xx/18xx/2000 8-bit Commodores (with a VCR as tuner they make excellent TVs). I just have 2 boxes of these seemingly useless bases which don't appear to fit my most treasured monitors. Yet I don't dare to toss them in case they actually fit on some of my monitors. Argggh !!
I think it's a rip-off that bases were never standardized.

Lawrence


Yes, I can understand that, L, but you're the one that asked me if you had shipped the base with the monitor because you found one where the Taxan used to be sitting LOL

Druid6900
June 22nd, 2009, 06:52 PM
Actually I was talking about a rubber inset on the base of the monitor. If you have an idea for identifying the tilt-base I could search thru the ones I have. Embarassingly, as a certified Atari ST freak, with about 5 ST monitors I can't find one that fits. I can't believe that of all these monitors I acquired there isn't one. Similarly for about 7 treasured 17xx/18xx/2000 8-bit Commodores (with a VCR as tuner they make excellent TVs). I just have 2 boxes of these seemingly useless bases which don't appear to fit my most treasured monitors. Yet I don't dare to toss them in case they actually fit on some of my monitors. Argggh !!
I think it's a rip-off that bases were never standardized.

Lawrence

I'll take a look (and picture) of the bottom of the monitor where the T/S base goes and maybe that'll narrow it down a bit.

Some monitors have pretty unique connector patterns and spacing is usually pretty non-standard too, so, if something is close, we'll start measuring.

Dwight Elvey
June 22nd, 2009, 08:50 PM
Great explanation Dwight...thank you!
And another thanks to Druid :).

ziloo

Hi
I should note that blowing EPROMs with simple test code
is an under used method of debugging.
Dwight

James0555
August 11th, 2009, 11:26 AM
It's a box I built a long while back that allows testing ICs, transistors and passive components in-circuit when hooked up to a dual trace scope (like the PP one I have) with X/Y capabilities and (after you get used to what the various curves are supposed to look like) allow you to run down the pins of ICs on a board and find open/short/leaky gates/components.

Is this the as what was called an octopus, used a transformer and some resistors I think, had a charts for differnt states such as shorts and opens?

I think I still have some info around here someplace.

Jim

Druid6900
August 11th, 2009, 07:47 PM
Is this the as what was called an octopus, used a transformer and some resistors I think, had a charts for differnt states such as shorts and opens?

I think I still have some info around here someplace.

Jim

Yes, it is the same thing and I have a file on this computer out-lining the contrustion of one. It's not really that difficult to build at all.

Yes, here it is now, complete with directions, theory of operation and samples of the "signatures"

James0555
August 12th, 2009, 03:19 AM
Yes that is it and I believe I have that same article. Also have one that was given to me a long time ago (early 70s I think) it was photocopied on that paper that is now fading away. Should find it and retype it as well. We had one in the shop I worked at in the AF back then. Worked great maybe time to build one.

Thanks.

Jim

kyeakel
August 12th, 2009, 04:43 AM
Lou,

Do you have more info on how to build the "Floppy Machine with Imagedisk and PUTR", that is one slick piece of equipment.

Kipp

skolapper
September 4th, 2009, 01:20 PM
Im looking to buy a 1979 900 but they seem hard to find. I have my eye on one at the moment that has a older restore done. How much should i plan on spending low and high? What should I look for? Thanks

Lou - N2MIY
September 4th, 2009, 03:26 PM
Kyeakel,

Sorry for taking so long to reply on this... The inspiration for the floppy machine is from Dave Dunfield : http://www.classiccmp.org/dunfield/img/index.htm

On that page, you'll see a link regarding connecting an 8" floppy drive to a PC. You'll also see info on imagedisk.

Twice I've written to him to thank him for the time he put into this, but I never heard back. He must be a busy guy.

All the drives are powered and connected to the PC at the same time. All I did is add toggle switches to switch the drive select lines. There is no magic here (that I can take credit for) whatsoever. But it sure is handy!

Lou

analog
September 16th, 2009, 07:40 PM
I've got an old HP logic analyzer... Very handy for figuring what I miswired on my homebrew cards :lol:

Like this:
http://www.leftfield.org/~dd/images/TE/HP1631D.jpg

Some versions of it have a few analog (scope) channels, but my model only has the pods ( digital inputs )

dave_m
September 16th, 2009, 08:02 PM
Some versions of it have a few analog (scope) channels, but my model only has the pods ( digital inputs )

The 1631D has two channels of sampled analog. Connect scope probes to the input BNC jacks on the front panel.

analog
September 17th, 2009, 03:16 AM
Yeah, I've got a 1630x - no analog inputs :-/

Couldn't remember the model number when I was looking for a picture; I did know that 1631 was close though :lol:

dave_m
September 17th, 2009, 06:35 AM
Yeah, I've got a 1630x - no analog inputs :-/

Couldn't remember the model number when I was looking for a picture; I did know that 1631 was close though :lol:

OK, I see. I have an HP1630G which I like very much. But it has only 8 timing channels and up to 48 state channels for microprocessor bus monitoring. The 1631D in your picture has up to 16 timing channels plus two digitized analog scope channels. Super machine for vintage troubleshooting.

I have used the HP1630 in Industry back in the 80's and have aways enjoyed its simplicity of use. Although the Tektronix and Gould Biomation analyzers were always more popular at my company.

channelmaniac
September 17th, 2009, 06:50 AM
By far and away I use the DMMs and Logic Probes the most.

Beyond that I have:

Dual Trace Oscilloscope
ESR cap meter
Function Generator
Logic pulser
CRT tester/rejuvenator
Frequency Counter
Computer Monitor Signal Generator (TTL/Analog, standard through XVGA resolutions)
Crystal tester
3 different EPROM programmers (one REAL old one for doing ancient chips)
Soldering/desoldering stations

And, The Internet. Useful for finding schematics or chip data sheets. (http://www.datasheetarchive.com)

RJ

Made a change! Traded off the Gould dual trace digital storage scope w/GPIB bus & integrated plotter.... and picked up a nice TDS-210 LCD scope from Tektronics.

WOW! That's one NICE scope!

Grabbed it last month off a guy on Craigslist while I was in Denver on our annual father/son road trip.

analog
September 17th, 2009, 03:09 PM
OK, I see. I have an HP1630G which I like very much. But it has only 8 timing channels and up to 48 state channels for microprocessor bus monitoring. The 1631D in your picture has up to 16 timing channels plus two digitized analog scope channels. Super machine for vintage troubleshooting.

I believe mine has 16 timing channels, I'll have to double check. I only have two pods though, I should get some more.