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I have an old A1 board with part number 671-0722-02, with a date of 1987 (design or manufactured?). I believe this part number is for a 2465B oscilloscope. Also, I can obtain a non-working 2445B for a low price. I am considering placing this 2465B A1 board in the 2445B chassis, clean it up, give it a hobbyist calibration. Will this give me a poor mans 2465B? What advice can the experts give me before setting out on this mission?

Tektronix wrote a series of 10 app notes pertaining to photometric measurements. The App Notes are as follows:

60-W-5750
58-A-2635
58-A-2702-1
58-A-2704-1
58-AX-2764-1
58-A-2912
58-A-2926-1
58-AX-3060-1
58-AX-3252
58-AX-3602

Does anyone know where I can get pdf copies of these documents?

grbosworth@...

From: Ronald Carlson <ronald.carlson.54@...>
To: [email protected]
Sent: Friday, March 2, 2018 10:29 AM
Subject: Re: Analog computing, X-Y display, was Re: [TekScopes] Wanted: Tek 503

Toby,


Also checking out Rolynn's suggestion of a 602 or 604 monitor.

Thanks, Ron



I've got a 608 monitor that works well..It was a piece of medical gear ..Dumped the med stuff and built the 'w7zoi Specan' into the vacant space...Has x,y,z outputs also for my eventual curve tracer
Jim

I decided to chase down the missing LO signal coming into the mixer. The oscillator signal is correct all the way through to U1040 output 9 at 10MHz. The output pin 12 of U1042A JK Flip Flop is divded by 2 with 5MHz on the output. However, output pin 8 of U1042B is still at 5MHz and at about have the voltage. It's suppose to dived by 2 agains down to 2.5MHz. Then it heads over to U1044. The output pin 12 of U1044 is dead. U1042 is very hot but the power rails are good. I say good. The 5v rail is about 4.85v through out the unit. I think U1042 maybe bad and even the decade counter U1044 could be bad. I guess I could pull these two chips and see if the 5v comes back up to a full 5v.

I found both chips at Very resonable.

Thank You!!

After persevering with Google Search I have found a few designs of
varying complexity
that could suit me, good old WW - now the fun begins.

Regards,

Dave

Dave, if you want to roll your own get a copy of 'Electronics and Wireless World"
DEC 2001 from yr local library. Page 922 has article 'Differential-in 100Mhz scope probe"
by Cyril Bateman. PC boards would not be available from him now, but his fully specified circuit and construction methods
should help you achieve your aim. and be easily down gradable to your target of 20MHz bandwidth with lower spec'd IC's
Some Specs are :

CMR : < 10Mhz >80dB>,70dB at 10MHz, 49dB at 120MHz (Ref 1V input and 10:1 attenuation set)

MAX4005 used inside the probes,MAX 4144 and MAX4107 used inside the direct input to scope
box. Copper pipe used for probe bodies.
Its also easy to calibrate and adjust. Cyril is (was?) a professional design engineer and a consultant
on capacitor design. He produced quite a few bits of pro spec'd test instrumentation in E&WW and his Cap esr tester is
likely to have been (and still be ) the most accurate esr meter so far ever designed for both enthusiast and semi pro work
I considered getting his PC boards at the time, but got myself a TEK P6046 and amplifier unit which both worked and were in spec
(If you are thinking of buying these be aware that not many are now in fully specified or even in working condition)

John

Hello--

I'm offering FS one each manual for a Tek 515/515A oscilloscope (no serial no.).

The manual is in VG condition (front cover missing a section near its
model-number window) and is unannotated.

I'm asking $5.00 plus USPS media-mail postage.

Questions welcomed, PayPal honored.

Thanks, and 73--

Brad AA1IP

Or find a Tektronix 536 oscilloscope and put identical plug-ins in the vertical and horizontal channels. Get a T plug-in with it so you have a time base if needed.

Byron WA6ATN

On Fri, 2 Mar 2018 18:48:31 -0300, you wrote:

Hello all,
First, thanks for all of you who gave me your inputs... In fact think I was
just seeking validation for the nonsense purchase which I was already
decided to do in my mind.
And I did...
The thing just arrived today and... well, it ended up to be less than a
bargain... But I`m not sure if it's a complete disappointment yet.

Let's see.

1. For sure, it's in really good mechanic and cosmetic condition... all the
knobs are intact, the markings are good, including of most of the push
button markings... (maybe except one or two).

I've heard tales of things wrapped in a layer of bubble wrap, and then
thrown off a UPS truck to land on the faceplate. By so much, you're
lucky.

2. It came with 2 7B53As (the additional one with option 5, in the right
vertical slot... Maybe good to uh... Raster!?). This second one is not
functional at all.

Then you've got spare parts at worst.

3. The vertical plugin (7A26) seems to be working fairly... But any
waveform greater than 4 div are clipped... I`m not sure if the mainframe
gain may be very low (or set such), so requiring the plugin's gain to be
increased beyond its dynamic range.
I don't think it's a problem of the vertical amplifier itself, as the
readout is showing well, close to the CRT's edges.

My memory says that the mainframe amplifier has several inputs (and I
could be wrong), one of which is the readout generator, one for each
vertical slot.

I'd try swapping the vertical and horizontal plugins. If the clipping
problem moves with the plugins, then that's one thing. If otherwise,
then you may or may not have a problem with the amplifier. You did
swap plugins, and I assume that the problem went with the plugin.

4. The "working" 7B53A is acting weird... It's sweeping backwards (from
right to left :-) quite funny) and in x1 magnification, it only fills about
3.5 divisions... Only with X10 engaged I can see a trace that crosses the
entire screen...

Not sure about this one, but a bias might be very off, this is
possible in op-amps, gain inversion.

Nevertheless, at x10, it seems the scan is fairly linear...(well, at x1
too, but rather compressed).

Could be a control, but I'm not sure. If the readouts are where they
should be, then I'm suspecting whatever's between the plugin (or the
plugin itself) and where the readout signal is injected. Follows for
both V and H plugins.

The MTB's timing seems to be responding well, getting slower CCW and faster
CW.
I can also see some upward bump of about 0.1div on the left end of the
trace (remember that the left end is actually where the end of the sweep
is) and a downward bump (of about the same 0.1 div) on the right end of the
sweep... I don't know what to think of that... maybe it's related to the
Hor. gain problem... Maybe it's some vertical channel switching artifact
(between the trace and the readout).
I also was able to engage the Delayed Sweep and it responds accordingly to
the DTB dial...
I can't engage the "MIX" mode... it seems the pulling knob is stuck. If I
pull it with a little more force, I can get it to show the DTB readout
while I keep pulling, but it doesn't stay there...It barely shows the
"yellow" band of the knob.

You might be able to roll the shaft between two marble plates (read
floor tiles), and that might straighten it out.

5. For the mainframe part, it seems the Readout is fully working,
reflecting the settings of both the vertical plugins, channel 1 and 2, and
the main time base and delay time base (as well as the x10 setting).

A very good sign is if they are where they are supposed to be.

The storage also seems to be working, maybe uncalibrated at worst, but I
have to dive a little bit more on the operation and the right function of
the buttons...The flood gun seem to be washing the CRT screen fairly evenly.

and hopefully, no screen burns.

6. The CRT... well that's where I have mixed feelings... For once, it's
definitely brighter than that of my poor 464...and that makes me happy
already, since I couldn't find a replacement for it.
But it also exhibits double peaking and a quite marked change of focus as I
increase the Intensity... But since the 7623A has Auto-Focus amplifier and
DC restorer (which the 464 lacks), there can be some plain electronics
fault at play.

Don't know enough about this to have an opinion.

Harvey

I will post some pictures as soon as I can take.

Do any of the above behaviors / defects ring your bells? Any First thoughts
are welcome!

I already downloaded from TekWiki the manuals (although I`m not sure I get
the SNs right) and, sure enough, I`m yet to go through all the usual first
steps... Check LV power supplies for Voltage and Ripple... Check the big
bulk capacitors... etc, etc...

Thanks in advance and Krgrds,

Fabio

Hello all,
First, thanks for all of you who gave me your inputs... In fact think I was
just seeking validation for the nonsense purchase which I was already
decided to do in my mind.
And I did...
The thing just arrived today and... well, it ended up to be less than a
bargain... But I`m not sure if it's a complete disappointment yet.

1. For sure, it's in really good mechanic and cosmetic condition... all the
knobs are intact, the markings are good, including of most of the push
button markings... (maybe except one or two).

2. It came with 2 7B53As (the additional one with option 5, in the right
vertical slot... Maybe good to uh... Raster!?). This second one is not
functional at all.

3. The vertical plugin (7A26) seems to be working fairly... But any
waveform greater than 4 div are clipped... I`m not sure if the mainframe
gain may be very low (or set such), so requiring the plugin's gain to be
increased beyond its dynamic range.
I don't think it's a problem of the vertical amplifier itself, as the
readout is showing well, close to the CRT's edges.

4. The "working" 7B53A is acting weird... It's sweeping backwards (from
right to left :-) quite funny) and in x1 magnification, it only fills about
3.5 divisions... Only with X10 engaged I can see a trace that crosses the
entire screen...
Nevertheless, at x10, it seems the scan is fairly linear...(well, at x1
too, but rather compressed).
The MTB's timing seems to be responding well, getting slower CCW and faster
CW.
I can also see some upward bump of about 0.1div on the left end of the
trace (remember that the left end is actually where the end of the sweep
is) and a downward bump (of about the same 0.1 div) on the right end of the
sweep... I don't know what to think of that... maybe it's related to the
Hor. gain problem... Maybe it's some vertical channel switching artifact
(between the trace and the readout).
I also was able to engage the Delayed Sweep and it responds accordingly to
the DTB dial...
I can't engage the "MIX" mode... it seems the pulling knob is stuck. If I
pull it with a little more force, I can get it to show the DTB readout
while I keep pulling, but it doesn't stay there...It barely shows the
"yellow" band of the knob.

5. For the mainframe part, it seems the Readout is fully working,
reflecting the settings of both the vertical plugins, channel 1 and 2, and
the main time base and delay time base (as well as the x10 setting).
The storage also seems to be working, maybe uncalibrated at worst, but I
have to dive a little bit more on the operation and the right function of
the buttons...The flood gun seem to be washing the CRT screen fairly evenly.

6. The CRT... well that's where I have mixed feelings... For once, it's
definitely brighter than that of my poor 464...and that makes me happy
already, since I couldn't find a replacement for it.
But it also exhibits double peaking and a quite marked change of focus as I
increase the Intensity... But since the 7623A has Auto-Focus amplifier and
DC restorer (which the 464 lacks), there can be some plain electronics
fault at play.

I will post some pictures as soon as I can take.

Do any of the above behaviors / defects ring your bells? Any First thoughts
are welcome!

I already downloaded from TekWiki the manuals (although I`m not sure I get
the SNs right) and, sure enough, I`m yet to go through all the usual first
steps... Check LV power supplies for Voltage and Ripple... Check the big
bulk capacitors... etc, etc...

Thanks in advance and Krgrds,

Fabio

I'm looking get get set up to be able to calibrate my own scopes. In reading the 485 manual a high frequency constant amplitude signal generator 100-350mhz is needed. If in the future I pick up a faster scope Should I get something more than 350mhz? Any recommendations? Asking here will save me from buying something that wont work for me. Thanks guys.

On 2018-03-02 3:31 PM, Ed Breya via Groups.Io wrote:

I'd recommend just using almost any analog scope that has X-Y capability for display. For low frequencies including audio, the response of the V and H should be virtually identical - you can easily check to be sure. Scaling is no big deal, and can be set up with the scope's range, variable, and position controls to whatever is needed. Even if not, a simple interface circuit should do the trick. You can also use a DSO if it has X-Y, to record very slow or single-shot experiments. Or, an analog storage scope.

I've found X-Y mode on a digital scope (TDS460A at least) to be
extremely unsatisfying. It seems to be far from the sweet spot of what
DSO's can do.

I've always had a soft spot for analog computers. Years ago, I had planned to build one, with lots of the usual function elements, and also some digital (kind of cheating) enhancements like A/D-EPROM-D/A operators for non-linear and arbitrary functions. The problem was that there were so many possible options that my tendency to overdo things would have made it a mind-boggling, complicated mess of functions and interconnect issues. So I never did it, but it's fun to think about.

When I think about such a project I think that a useful role for digital
would be in the (re)configuration of a module fabric (e.g., analog
crossbar switches).

There is also this:

But this is probably off topic by now...

--Toby

Until this discussion came up, I had no idea that analog computers are still so popular in some circles - looking online a little now, I see that they are alive and well to some extent, even though PCs and SW can do all that and more. There's something to be said for the real thing, hands-on experience.

BTW, I stumbled upon a manual for the GP-6, that appears to include all the circuit schematics. If you haven't found this already, here it is:


Good luck,
Ed

On Fri, 02 Mar 2018 18:39:11 +0000, you wrote:

3D printing can be a bit picky about settings. The smaller the layer
setting the denser the part, and the more rugged it will be. Extruder
temperature also plays a part.

Harvey

On Thu, 1 Mar 2018 at 15:59 Malcolm Hunter <malcolm.r.hunter@...>
wrote:

It can be done. I've 3D printed feet for the 465 based on this model I
"designed" based on the original feet:
. Printed in PLA, they are
functional but I wouldn't bank on them holding out for every day use.
Someone with a bit of 3D modelling ability and an original foot should be
able to craft a suitable replacement for the 335 too. Printed in something
a bit more durable would work and even if they weren't as good as the
original, you could have plenty of spares.

There are now services that'll demand-print and ship items, like e.g.
ShapeWays, which will print in a variety of materials. It'd be nice to have
a stash of 3D models for Tek replacement parts cataloged someplace, and/or
to have them listed on these print services.

I modeled the PCB bracket I needed for my FG504, but the PLA prints I got
from the 3D printer I have access to delaminated as soon as I put a screw
to them. The ShapeWays nylon print, however, worked just fine (see <
>),
and I know other people have had luck with the same print.

I priced out your thing on Shapeways, and the two materials/methods that
look likely are:

- Strong & Flexible Plastic Black (Selective Laser Sintering): $8.98.
- HP Nylon Plastic Black (Multi Jet Fusion): $17.96.

though perhaps it'd be possible to bring down the per-item cost for e.g. a
set of four by optimizing the design...

I'd recommend just using almost any analog scope that has X-Y capability for display. For low frequencies including audio, the response of the V and H should be virtually identical - you can easily check to be sure. Scaling is no big deal, and can be set up with the scope's range, variable, and position controls to whatever is needed. Even if not, a simple interface circuit should do the trick. You can also use a DSO if it has X-Y, to record very slow or single-shot experiments. Or, an analog storage scope.

I've always had a soft spot for analog computers. Years ago, I had planned to build one, with lots of the usual function elements, and also some digital (kind of cheating) enhancements like A/D-EPROM-D/A operators for non-linear and arbitrary functions. The problem was that there were so many possible options that my tendency to overdo things would have made it a mind-boggling, complicated mess of functions and interconnect issues. So I never did it, but it's fun to think about.

Until this discussion came up, I had no idea that analog computers are still so popular in some circles - looking online a little now, I see that they are alive and well to some extent, even though PCs and SW can do all that and more. There's something to be said for the real thing, hands-on experience.

BTW, I stumbled upon a manual for the GP-6, that appears to include all the circuit schematics. If you haven't found this already, here it is:


Good luck,
Ed

Thanks for the extra info. I certainly wish I could peer over your shoulder, I'd probably learn a lot.

A very cheap X-Y option right now is a 1720 vectorscope, if that has the bandwidth you need; it's one of the devices I'm using to test my circuit with. They are small, lightweight, and currently cheap on ebay (there's a $10 one right now). The 60x family seem to be very hard to find these days (although a friend bought a 603 from Sphere recently, which I am about to try out).

--Toby

On Thu, 1 Mar 2018 at 15:59 Malcolm Hunter <malcolm.r.hunter@...>
wrote:

It can be done. I've 3D printed feet for the 465 based on this model I
"designed" based on the original feet:
. Printed in PLA, they are
functional but I wouldn't bank on them holding out for every day use.
Someone with a bit of 3D modelling ability and an original foot should be
able to craft a suitable replacement for the 335 too. Printed in something
a bit more durable would work and even if they weren't as good as the
original, you could have plenty of spares.

There are now services that'll demand-print and ship items, like e.g.
ShapeWays, which will print in a variety of materials. It'd be nice to have
a stash of 3D models for Tek replacement parts cataloged someplace, and/or
to have them listed on these print services.

I modeled the PCB bracket I needed for my FG504, but the PLA prints I got
from the 3D printer I have access to delaminated as soon as I put a screw
to them. The ShapeWays nylon print, however, worked just fine (see <
>),
and I know other people have had luck with the same print.

I priced out your thing on Shapeways, and the two materials/methods that
look likely are:

- Strong & Flexible Plastic Black (Selective Laser Sintering): $8.98.
- HP Nylon Plastic Black (Multi Jet Fusion): $17.96.

though perhaps it'd be possible to bring down the per-item cost for e.g. a
set of four by optimizing the design...

Toby,

Documentation is just a notebook, a few pics before disassembling anything important.
Analog computers are two Comdyna GP-6. FWIW, the system could modeled in MatLab, Mathematica, or even MathCad. This project is modeling some audio transfer functions - it will be quicker for me to optimize by seeing and hearing the residual errors. For the display a vintage Tektronix 503 will do; has identical X and Y amplifiers so additional scaling circuitry and their effects is eliminated.
Also checking out Rolynn's suggestion of a 602 or 604 monitor.

Thanks, Ron

On 2018-03-02 12:25 AM, Ronald Carlson wrote:

Anyone have a Tek 503 that's looking for a new home?

The 503's specs fit nicely as an output display for an analog computer project I'm working on.

I'm curious about your analog computer. Are you
documenting/blogging/video'ing this anywhere? What is the goal?

I'm also working on circuits to drive X-Y displays, but at a very basic
level since I'm an electronics beginner.


--Toby

Or, perhaps there's a better, newer model the group could recommend?

The identical low frequency response horiz and vert amplifiers with a
square display make it initially an interesting option.

TIA, Ron

It is made on laser engraver. I have a friend that work on this machine and I make a corel with outlines and what need to be on scale.
it is made from black PVC foil past on Plexiglass.
First cut the foil on low power to remove the foil only and after this cut outline on big power.
I'm not sure which one will illuminate better, but will test all 3 before to choose one. Think this one with black foil back will be better then other because will illuminate only the scale on top of the LED.
I hope in next week to find a time to go to make the knob and will make some pictures with all installed.

I have been refurbishing some late 70s-early 80s HP gear and I only replace bad capacitors per ESR or Q meter readings. A schematic helps in making sure there are no other elements in parallel that would skew the results. Many power rail caps are in parallel so I just lift their one end and measure that way.

I have found several bad tantalum slug capacitors - I replace those with modern equivalents that often have similar part numbers and look very similar or identical. Those are not particularly cheap and I always replace the hermetic ones with new hermetics, not the cheaper yellow plastic encapsulated ones.

If a given type of a capacitor has failed more than once in a given instrument, I replace all - if there’s less than 5 or 6 total. Otherwise I do a judgment call based on circuit types and the stress the part is likely to experience.

The failure mode for tantalums that I checked was almost always high ESR or high DF, and capacitance changes were secondary and not always present.

I also test all electrolytics after 24hrs of preforming/burn-in at room temp. They seem to fail randomly and I also shotgun those that see lots of stress if any compatriots have failed. For me, they almost always fail with both ESR/DF and capacitance changes. I would still advise having a good ESR meter in addition to capacitance meter.

In some units there is a lot of failed electrolytics, in some others - few if any. I don’t have enough experience to see a clear pattern there yet.

Kuba