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I got this piece new-in-the-box a last year and I've finally powered it up & checking it out. Even the battery seems ok. It must be time for me to start digging through the history of the group and this scope. First need to see if it can talk to my computer.
Ron

On Tue, Jan 21, 2025 at 02:35 PM, vk2bea wrote:

but I don't see where to actually set the pattern that is matched.

OK, I did overlook the paragraph...

a. Turn the Δ REF OR DLY POS control to the clock mode character, the qualifier bit, or a digit of the word.
b. Turn the Δ control to define the underlined character. Digits of the word can be set to 0, 1 , or X with BIN radix, 0 to 7 or X with OCT, and 0 to F or X with HEX . Note that the clocking edge can be redefined here.

I've looked over the 2465B manual but I can't for the life of me find where it describes setting the word recognizer pattern.

I can set the trigger to trigger on the word recognizer match and I can change the radix but I don't see where to actually set the pattern that is matched.
If anyone knows ... please let me know!

On Tue, Jan 21, 2025 at 12:15?PM Keith via groups.io <keith=
[email protected]> wrote:

The initial step of probing TP800 and twiddling the delta ref knob seemed
straightforward, but I'd love to know what this is for, the manual does not
say.

...

I believe I was able to get up to step 16 correct, but the next steps
(starting from 17) baffled me. The manual says connect the time marker to
both the 2465B and a second scope's CH1, and the Gate Out of the 2465B to
the second scope's CH2 and trigger off that channel. But then the next
paragraph (jj in the manual) completely confused me. What is it all about?
What's the purpose of the second scope, what is a 'usable time mark' ? It's
as clear as mud.

Hey Keith,

I remember wondering the same things when I calibrated my 2467, though at
the time I didn't understand enough of how these scopes work to do more
than follow the instructions.
There is some mention of calibration and calibration constants in the
Theory of Operation section, maybe that'll help?

The principle involved is that you first calibrate the CRT and the cursors,
and then everything else is adjusting gains & offsets to a given time
reference to align sweep times, and delay offsets (I believe) to the
calibrated CRT (and cursors), as well as calibrating the the two sweeps (A
and B) with respect to each other. Note that sweeps on these scopes are
calibrated even with the horizontal VAR control out of detent, which is not
the case for earlier scopes (I believe).
The sweeps need their delays calibrated as you can e.g. measure time delays
with dual delay display and e.g. overlaying edges or waveforms. The A sweep
delays can be calibrated by displaying the B-trace after a delay (or dual
delays), but the B-sweep delays are calibrated by looking at the B sweep
gate, I believe.
If you look at the sweep schematics, you'll see that the delay gate of the
B-sweep hybrid is routed to the sweep gate output, which I believe is only
useful for calibration, and hence I believe the steps using the B-delay
gate are calibrating the B-sweep delay.
It's been a while since I dug into this. I'm fairly sure I never sussed out
the purpose of each of the steps, and my reasoning might have been off to
begin with, but maybe you'll figure this out?

... time passes ...

Now that I think about it, I can see how the A sweep delay(s) are used to
highlight the A sweep, as well as to implement B delay sweeps and dual
delay sweeps. I'm struggling to figure out what the B sweep delay reference
is actually used for. After reading the ToO section, I believe the B-sweep
may be used for options to measure stuff, maybe e.g. pulse timings, meaning
it'd need calibrated delays?

Siggi

John,

Look for pots R2918 and R2931 on the A5 board. These are the centering and gain. Usually the centering pot is centered and the gain is adjusted. Resistors R710 and R910 on the A1 board could be too high. The latter is for the horizontal section. These I replaced with a pair of 20meg 1% in series in my B version. The original 39 meg 1/4W carbons were almost 60 meg in mine.

Mark

Hi All. On my 2465A the scale factors are readable and seem to be accurate but they are nearly off the bottom of the screen. I have to look at an angle to read them. Is there an adjustment that is necessary to bring them back into view? Or do I just need to learn to stand on my tip toes!

Everything else seems to fine with the scope... but this is pretty annoying.

Thanks in advance for any advice.

John w.
N7ZMG

So I started to go through the cal steps - the power supplies, DAC ref and CRT (cal08) steps seem reasonably straightforward. Then I tried cal01, the horizontal cal step.

The initial step of probing TP800 and twiddling the delta ref knob seemed straightforward, but I'd love to know what this is for, the manual does not say.

Oh well, onto the next step, connect up a time mark generator. I used the Siglent function generator, it seems to be adequate when using it in Pulse waveform mode, specifying the period e.g. 0.1mS where it says set the time markers. You need to set a suitable pulse width, not too large but not so small that the pulses become difficult to see. But it seems adequate.

I believe I was able to get up to step 16 correct, but the next steps (starting from 17) baffled me. The manual says connect the time marker to both the 2465B and a second scope's CH1, and the Gate Out of the 2465B to the second scope's CH2 and trigger off that channel. But then the next paragraph (jj in the manual) completely confused me. What is it all about? What's the purpose of the second scope, what is a 'usable time mark' ? It's as clear as mud.

- Keith

Thank you David.

I am very curious to see any data on their tunnel and pin diodes.

On Tue, Jan 21, 2025 at 10:20?AM david via groups.io
<davide_us@...> wrote:

I will check for them there. I don't remember where I got them from, will look there.
David

I will check for them there. I don't remember where I got them from, will look there.
David

Did as you suggested, main TB at 5ms/div and delayed at 5us/div, sync in from VSync. Got what I needed from an excellent but faint display. Now to deal with the revealed issue (NOR gate coupled to an SR Latch, to truncate the VSyncso it starts immediately after the end of the last line in the frame is complete).

Thanks for the steer. - much appreciated

--
Christopher Hilton-Johnson
The Stone Barn
Cottisford
Oxfordshire
NN13 5SW

07831 458867

Are they on the TekWiki and KO4BB sites? They would be the best places to
archive them if they are not already there.

DaveD
KC0WJN


On Mon, Jan 20, 2025 at 16:33 david via groups.io <davide_us=
[email protected]> wrote:

I have a PDF File titled - "TEK_XREF_TUNNEL_DIODES", also have a PDF file
- "TEK-MADE INTEGRATED CIRCUIT CATALOG" If you would like them, I will
upload to files directory.
David

I have a PDF File titled - "TEK_XREF_TUNNEL_DIODES", also have a PDF file - "TEK-MADE INTEGRATED CIRCUIT CATALOG" If you would like them, I will upload to files directory.
David

Hi all,

I thought it might be useful to share my updated conclusion. My fix tamed the problem somewhat, but not enough to make it fully usable, so I replaced it with a compatible tube, which was a 154-0731-00 from a 465. This solved the problem: the display is now perfect, pin-sharp, constrasty and, more importantly, it remains so over time.

Besides, I found what seems to be the explanation in a document available on Tekwiki, discussing the Tektronix CRT reject codes:



More specifically, code R324 (page 5) entitled "Spurious mesh emission" is described as causing "a glowing spot or area which persists after the beam is removed" - well, well!. This is caused by "MgO particles not properly covered by aluminum [on the surface of the scan expansion mesh]". And, "It also appears if the aluminum is not conductive because of oxidation", which, I suppose, might explain why some tube develop this problem after several years, as aluminum deteriorates. So in conclusion, the tube is basically dead when it starts glowing, and there is no other cure than replacing it.

I hope this can be useful to those experiencing the same problem.

Raymond ACK on all,

I forgot about " show quoted text" to see interleaved response.

I referenced Jim W avalanche and Tek TD pulsers only as possible alternatives to Leo Bodnar, the gold standard

The PG506 is reasonable on fast but nowhere near as good the Leo B. I never used the avalanche JW.

I tried old Tek TD pulser adapter, but tweaky, high level input required.

Am lucky to have two of the old versions of the Leo Bodnar, handy to compare two plugins or channels.


Jon

The following items have been added to the Files area of the [email protected] group.

* /070-6860-00.Tektronix.2465B-Operators.Manual.pdf ( /g/TekScopes/files/070-6860-00.Tektronix.2465B-Operators.Manual.pdf )

*By:* vk2bea <vk2bea@...>

*Description:*
070-68860-00 2465B / 2455B / 2445B Oscilloscope - Operators manual (high quality scan with navigation links)

Sorry for delay and thanks!

I should probably mention that the schematics are NOT 100% accurate. What has been published is a scan of the last pre-production drawings. A final production set was never completed because there was never the intent to publish the finalized schematics in the manual. Most of the errors on the schematics are typos in captioning or incompleteness. For example, on several of the drawings there were added hand written information intended to be included in the next revision, Where there is a single line connecting two or more components but signifying a bus, an added slash with a number indication the number of conductors has been added. Other errors are obvious typos, +15VAC or -5VAC for example which are on the Front Panel schematics should be +15VDC and -5VDC respectively. To my knowledge there are no AC voltages present within the instrument other than the "line trigger" signal from the Auxiliary Power Board <A07>. I am not aware of any incorrect IC designations nor module interconnect errors.

Best regards,

Ferrous

It seems to me there was a pressure device for forcing cleaner around the shafts. It screwed onto the mounting and pushed cleaner in around the bearing. Have not seen one for years.
If these are the Allen-Bradley/Ohmite type pots you can pry off the back coverings and use Deoxit faderLube on them. Takes some care. The little tabs on the covers can be bent back into place to hold them. These are very good pots but, because they can't be easily cleaned, often develop bad spots or get noisy. I have even heard of drilling holes in the caps but would worry about particles getting into the pot.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

Firstly, thanks for all the helpful, and generous, responses.

I decided to dribble Deoxit ‘down’ the spindle entry and it appears that it may well have got to the track and adjustment is very much improved. I hadn’t expected this to work.

Too early to confirm success but I’ll give it (a) some more and (b) some more time and retry tomorrow.

Hey Ferrous,

This is amazing, it's sure to extend the life of some of those TDS420/460
scopes that otherwise would have been landfill - thanks!

Siggi

On Fri, Jan 17, 2025 at 1:36?PM Ferrous Steinka via groups.io
<ferrous.steinka@...> wrote:

Although not 100% accurate schematics for the TDS400 series have been
posted to the files section of this group as well as TekWiki. They were
scanned from "C" and "D" size engineering drawings and then converted
mostly to "A" legal size. These were late pre-production drawings and did
not contain the power supply (not Tek made). I did not have access to
final engineering drawings. No manual was ever published by Tektronix for
the TDS400 series which contained schematics or parts layout drawings or
pictures. Being the first all digital oscilloscope which relied
extensively on microprocessor control, it was new territory. The next
series, TDS500, had manuals which were similar to past Tek manuals complete
with schematics, theory of operation, and pictures.

I have no background in manual writing or compiling, just a technical
background working at Tektronix for about 30 years. I was able to obtain
the drawings from one of the engineers who designed the TDS series, now
passed on. I tried to post on TekWiki but was not savvy enough to figure
out the posting process.

I had sent a couple of the trigger related schematics to Tim Wright who
was having triggering issues with his TDS420 in hopes it would help him
find his problem. I then posted all my jpg files to the cloud and informed
Tim that they were available for him to use. Kurt Rosenfeld at TekWiki has
also been informed of the existence of the schematics.

Both Tim and Kurt have assembled my jpg images into a single pdf file. I
thank them both for doing something that I had been unable to do which
resulted in my work to be available to those who may need it. The TekWiki
availability is here:
- or:


The schematics are available in the Group files section here:

/g/TekScopes/files/Tektronix%20TDS420_460%20Schematics.pdf

Best regards,

Ferrous Steinka