Asking for Help with Verifying Genuineness of 2465B from Ebay


Mr. Eric
 

Hi Everyone,

I just purchased a 2465B from ebay. I'm trying to verify that it actually is a 2465B and not a rebadged and hacked lower bandwidth tek scope. From my understanding the best way is the serial number from the A1 board which I got. 670-9268-07. I looked up in the service manual and I saw that the A1 boards listed were:
670-9268-02
670-9268-04
670-9268-06
But I didn't see any mention of my A1 board: 670-9268-07 in that manual.

I also noticed that the last 2 digits "07" on my A1 board is actually a little white sticker with 07 written on it. I looked under the sticker and I didn't see anything else.

I'm a little thrown off, and I was wondering if anyone here had more insight to this. I just want to make sure that I indeed did get a genuine 2465B as I know others in this group have gotten "burned" on ebay. I did not purchase this 2465A from the ebay seller that has been mentioned in a few posts for hacking 2445s into 2465As.

Thanks in advance everyone!!!
Best Regards,
Eric


Jean-Paul
 

Who was the seller:

There are some unethical Epay sellers that had many such issues.

You should be suspicious of such sellers. Board numbers ar enot definitive and the white suffex 2 digit sticker is normal.

What was the epay lot # ?

Jon


Jean-Paul
 

Eric: Notice that 2465, 2465A and 2465B are different entirely, though in the same series.

Check the A5 control board see if any SMD tant leaking.

Does it pass CAL and all self tests?

Check BW and transient response?

Jon


Chuck Harris <cfharris@...>
 

There are a number of ways to tell the authenticity of the
board:

1) Look in the section where the transient adjustments live.
You will see two pots, and several small trimmer capacitors
all grouped together. The 2465B also has a small unsupported
air core coil (L403) with a scrunched up appearance; the 2445B
does not have this coil.

2) Look to the front side of U900. The 2465B has three square
trimmer pots R801, R802, and R850, that form an "L". The 2445B
only has two, as it is missing the "TRANSIENT" response trimmer pot.

3) Look in the triangular space framed by U400 hybrid, U500 hybrid,
and the angular section of the brown plastic pusher for the power
switch. In that section, there should be a square trimmer pot
labeled "HF ADJUST" on a 2465B. The 2445B does not have that pot.

4) Look to the back of the chassis side of U600. You should see
two square trimmer pots and a white adjustable inductor in a row.
In the open space between those pots, and below the doglegged
brown plastic actuator bar for the power switch, there should
be a "G" drawn with a Sharpie marker. In the immediate vicinity
of that "G", you should see 6 via's, two narrow, two wide, two
narrow on a 2465B. On a 2445B, you will see two circles with
solder filled vias in their centers, with a rectangle between them.

There are more component changes, but the above should suffice for
identifying which scope you really have.

-Chuck Harris

Mr. Eric wrote:

Hi Everyone,

I just purchased a 2465B from ebay. I'm trying to verify that it actually is a 2465B and not a rebadged and hacked lower bandwidth tek scope. From my understanding the best way is the serial number from the A1 board which I got. 670-9268-07. I looked up in the service manual and I saw that the A1 boards listed were:
670-9268-02
670-9268-04
670-9268-06
But I didn't see any mention of my A1 board: 670-9268-07 in that manual.

I also noticed that the last 2 digits "07" on my A1 board is actually a little white sticker with 07 written on it. I looked under the sticker and I didn't see anything else.

I'm a little thrown off, and I was wondering if anyone here had more insight to this. I just want to make sure that I indeed did get a genuine 2465B as I know others in this group have gotten "burned" on ebay. I did not purchase this 2465A from the ebay seller that has been mentioned in a few posts for hacking 2445s into 2465As.

Thanks in advance everyone!!!
Best Regards,
Eric






Craig Cramb
 

This a a repost of Chuck Harris description of a 2445b to 2465b hack job. Maybe this will help you find out if you are dealing with a true 2465B.

This information was obtained by searching Tektronix 2465, 2465A, 2465B


Briefly, because I have discussed this before:

1) Replace the labels that say 2445B with labels that say 2465B.
2) Add a jumper to the A1 motherboard connector that goes to the
A5 controller. This jumper misrepresents the scope type as a
2465B to the controller. The controller, thinking it has
a 2465B motherboard enables the 5ns/div step on the timing switch.
3) Isolate the two spiral inductor networks, by cutting traces, and
solder in a pair of jumper wires to bridge the signal path.
4) Do your level best to tweak the response as a 2465B, even though
you are missing 3 trimmer pots, 1 inductor, and a spiral delay
line matching network; have 3 wrong valued trimmer capacitors and
several wrong valued resistors; and your scope uses graded
vertical preamp hybrids that were culled out after production
because they could not meet the 2465B performance requirements.

Seems like a poor thing to do to your 2445B, but what do I know, I'm
just a dumb engineer.

-Chuck Harris


 

On Mon, Dec 21, 2020 at 07:15 AM, Mr. Eric wrote:


But I didn't see any mention of my A1 board: 670-9268-07 in that manual.
Your topic says 2465B and in the text you mention both 2465A and 2465B.
The board number you mention was used only in 2465A so I guess that's what it is.
670-9268-xx was use in 2465A and 2467 with latest last digits of -09 for 2465A and -10 for 2467.
2465B and 2467B used 671-0722-xx with latest last digits of -16 for 2465B and -17 for 2467B.
/HÃ¥kan


Mr. Eric
 

Thank you everyone.

Yes Zenith, I messed up the title and wrote 2465B, I meant 2465A in the title. Thank you for catching that.

It is definitely not a 2467, no microchannel plate crt.

So it sounds like the consensus is that a 670-9268-07 A1 board is a 2465A, and the 07 just refers to a revision of the board that was made after the published date of the 2465A/2467 service manual that I have and therefore the revision 07 is not mentioned in it.

The ebay seller was picky2000. I had searched the messages of this group and didn't find anything negative about this seller which is one of the reasons I bought it from him. What threw me off was that the description said calibrated and tested, but when I received it the trace rotation was wayyyy off and the geometry setting is noticeably off too. Voltage levels look good, but I only have a basic 15Mhz function gen to test with, I don't have a leveled sine-wave gen to do any better tests.

I did a basic bandwidth test using the leobodnar 30ps risetime pulsegen and I measured a risetime of 1.09ns on this 2465A. I have another 2467 that with the same test shows a risetime of 0.98ns. I was hoping that my 2465A would be a little closer to 1ns. According to what I have read 1.09ns indicates a BW of 0.35/1.09ns = 321.1Mhz (assuming a gaussian response). It was set to the 50ohm load setting. How accurate or adequate of a test this is, I'm not sure...

The 2465A does pass all self tests and the Cal 05 shows Hrs On 1508 PWR On/Off 620, I know the hours can be changed but the CRT looks really good, clean and crisp compared to my 2467 which has 22584 hours, so it would be nice to think that my 2465A actually does have 1508 hours.

Thanks for all the help everyone and sorry for messing up the title.


 

Eric wrote:

What threw me off was that the description said calibrated and tested, but when I received it
the trace rotation was wayyyy off and the geometry setting is noticeably off too.
My impression (please correct me if I'm wrong) is that trace rotation is a correction for the local magnetic field, which is why it is an operator control. If the scope was calibrated (or even merely adjusted) to look good at one location (e.g. San Francisco) then it MUST be out of rotation at a significantly different location (e.g. Chicago). I'd expect that even the frame of a building, or nearby electrical, laboratory, or medical devices could affect the rotation.

-- Jeff Dutky


Jean-Paul
 

To Jeff: The TEK CRTs have a fine MuMetal CoNetic shield and are NOT affected by earht or other ext mag fiedls of normal gauss level.

To Eric: >>trace rotation was wayyyy off and the geometry setting is noticeably off too.>>

I have bought many 246x/A/B, never seen that isse.

For the GEOM and ROT "WAY OFF" the trimmers were either maladjusted and NEVER properly set OR the scope was poorly packed and the freight vibration somehow rotated the pots.

More likely scenario: Pots are old and scratchy.

Even if set, they may not have moved in decades.

EVERY old scope potentiomètre controls and trim pots may need cleaning and exercise.

I am sure our mavens like Chuck can shed more light on this.

Enjoy!

Jon


TomC
 

On 12/21/2020 11:26 AM, Mr. Eric wrote:

I did a basic bandwidth test using the leobodnar 30ps risetime pulsegen and I measured a risetime of 1.09ns on this 2465A. I have another 2467 that with the same test shows a risetime of 0.98ns. I was hoping that my 2465A would be a little closer to 1ns. According to what I have read 1.09ns indicates a BW of 0.35/1.09ns = 321.1Mhz (assuming a gaussian response). It was set to the 50ohm load setting. How accurate or adequate of a test this is, I'm not sure...
Using Leo Bodnar's pulse generator, my 2465 (no A or B) measures 0.91 nsec. So there seems to be something not right with your 2465A. It should be better than my 2465. And your 2467 should certainly be substantially better.

Did you have the horizontal sweep in X10 mode? I used X10 mode and the 0% 10% 90% and 100% graticule lines. Rise time measured using the cursor lines.

Tom


 

On Mon, Dec 21, 2020 at 08:41 PM, Jeff Dutky wrote:


I'd expect that even the frame of a building, or nearby electrical,
laboratory, or medical devices could affect the rotation.
Gravity is a factor. Placing it vertically/horizontally makes a difference. Magnetism would be a very important factor were it not for the mu-metal shield around the CRT. Whether it deserves to be called "wayyyy off" is a matter of opinion. A change of rotation of one, max. two minor divisions across the horizontal would be normal under normal conditions..

Raymond


Mr. Eric
 

Jeff,

That's very interesting, I had no idea that the local magnetic field would have such an impact. But that completely makes sense why its an operator control. Thanks for that info.

I will say though that after looking at the ebay images in more detail, the trace rotation is off in the seller's pictures as well =) Would this also have an effect on the geometry? I'm judging geometry by the delta_t cursor lines, they are mildly bowed in the center of the cursors toward the center of the crt. However this might just be a failure of understand on my part and the cursors being slightly bowed has no bearing on an actual signal...

Realistically, the seller probably just said calibrated and didn't actually adjust anything, or did the absolute bare minimum


 

On Mon, Dec 21, 2020 at 08:58 PM, TomC wrote:


Using Leo Bodnar's pulse generator, my 2465 (no A or B) measures 0.91 nsec.
I've found the automatic parametric tests in this family inaccurate and varying in their results.
Of course, rise time measured depends on overshoot. Accepting 3% - 5% overshoot during rise time adjustment (not uncommon) results in significant shorter rise time than accepting "0%" overshoot.
Converting observed rise time into BW, especially with different step sources is not something to specify within 0.1%. 1% complies more with "the truth".

And your 2467 should certainly be substantially better.
AFAIK, the 2467 has the BW of the 2465A, 2465B and 2467B both have a specified BW of 400 MHz.

Raymond


 

On Mon, Dec 21, 2020 at 09:10 PM, Mr. Eric wrote:


Realistically, the seller probably just said calibrated and didn't actually
adjust anything,
I love this! As has been written before, "calibrating" in its pure sense means nothing more than comparing against something considered a standard. Without specifying the results, i.e. deviations, it means nothing.

That "standard" only makes sense if its deviations from some agreed standard are known and within specified limits. "NIST calibration" means compared against ...

Raymond


TomC
 

On 12/21/2020 12:11 PM, Raymond Domp Frank wrote:

AFAIK, the 2467 has the BW of the 2465A, 2465B and 2467B both have a specified BW of 400 MHz.
Any of the above (whether 350 or 400) should be better than my 300 MHz 2465 that has a rise time measured at 0.91 nsec.


Chuck Harris <cfharris@...>
 

Trace rotation can change if you bang the scope around....

But more likely is that "calibrated and tested" means that
it was calibrated and tested at some point in its life.

I would expect an A to be about 1ns rise time.

trise = 0.350ns/fbw(in MHz) -> 1ns.

I don't hold much confidence in the trise measurements
these scopes make for themselves...

Note, that the screen is all marked out for trise measurements.
The 0% and 100% markings at full scale are for the flat tops,
and flat bottoms of the waveform. The measurement is at the
10% and 90% graticule lines.

Many seem to think that the full scale is for the peak spike,
but it really isn't a part of the measurement.

-Chuck Harris

Mr. Eric wrote:

Thank you everyone.

Yes Zenith, I messed up the title and wrote 2465B, I meant 2465A in the title. Thank you for catching that.

It is definitely not a 2467, no microchannel plate crt.

So it sounds like the consensus is that a 670-9268-07 A1 board is a 2465A, and the 07 just refers to a revision of the board that was made after the published date of the 2465A/2467 service manual that I have and therefore the revision 07 is not mentioned in it.

The ebay seller was picky2000. I had searched the messages of this group and didn't find anything negative about this seller which is one of the reasons I bought it from him. What threw me off was that the description said calibrated and tested, but when I received it the trace rotation was wayyyy off and the geometry setting is noticeably off too. Voltage levels look good, but I only have a basic 15Mhz function gen to test with, I don't have a leveled sine-wave gen to do any better tests.

I did a basic bandwidth test using the leobodnar 30ps risetime pulsegen and I measured a risetime of 1.09ns on this 2465A. I have another 2467 that with the same test shows a risetime of 0.98ns. I was hoping that my 2465A would be a little closer to 1ns. According to what I have read 1.09ns indicates a BW of 0.35/1.09ns = 321.1Mhz (assuming a gaussian response). It was set to the 50ohm load setting. How accurate or adequate of a test this is, I'm not sure...

The 2465A does pass all self tests and the Cal 05 shows Hrs On 1508 PWR On/Off 620, I know the hours can be changed but the CRT looks really good, clean and crisp compared to my 2467 which has 22584 hours, so it would be nice to think that my 2465A actually does have 1508 hours.

Thanks for all the help everyone and sorry for messing up the title.






Mr. Eric
 

Chuck,

When I take the rise time measurement, I'm using the var knob of the volts/div in order to scale the flat top and bottom of the squarewave to the 0% and 100% graticules. I then use the deltaT cursors at the intersection of the 10 and 90. I will give a thanks and shoutout to W2AEW for his videos that teach these things. I've been wondering for half my life on why I would want an uncalibrated volts/div....

So ideally a 2465A should be producing a risetime measure of 1ns and I'm getting 1.09ns. That's unfortunate. Is it possible for this to be calibration or a dying cap in some filter in the front end? I will say that the inside of this scope is pretty clean which was really nice to see...

The only things I have for testing is the Leobodnar 30ps pulser and HP 8656A Signal Generator 0 to 990Mhz that has a calibration sticker from 2013 that says, calibration not required, for reference only =)


 

On Tue, Dec 22, 2020 at 01:46 AM, Mr. Eric wrote:


So ideally a 2465A should be producing a risetime measure of 1ns and I'm
getting 1.09ns. That's unfortunate. Is it possible for this to be calibration
or a dying cap in some filter in the front end?
There are quite a number of things that influence the observed rise time.
To name a few that are easily overlooked:
- The horizontal (time) calibration of the 'scope
- The type, quality and length of the cable between pulse generator (PG) and 'scope.
- The impedance matching (SWR) between PG and 'scope
- The *actual* waveform from the PG
- The amount of (acceptable) overshoot when adjusting the step response: Almost always some overshoot is needed for the 'scope to attain its spec'ed BW. Often, step response adjustment specifies or specifically allows for it.
- The amplitude of the pulse and the scope's V/div setting

Raymond


 

On Tue, Dec 22, 2020 at 02:13 AM, Raymond Domp Frank wrote:


So ideally a 2465A should be producing a risetime measure of 1ns and I'm
getting 1.09ns.
It's incorrect to say BW can be measured by measuring rise time. It depends on the 'scope's characteristics, the exact step shape (slew rate, over/undershoot, flat). Rise time gives an indication of flatness across a certain frequency range. In practice, direct BW measurement/specification is used and an approximate derived rise time is given. The TDS3000-series comes to mind but there must be many others.
Why is that?
Observe a sine wave, with a frequency known to within a few percent, with constant level at the 'scope input, and make sure that impedances of sine wave generator and 'scope input are well matched.
Observe the amplitude on the 'scope, starting from a frequency where the 'scope has "100% amplitude" and increase the frequency while observing the decrease in amplitude on the 'screen, until the amplitude is 100% - 3 dB, or about 70.7% of the original amplitude. There's your upper BW limit. In practice, you'll almost always see some wobbling when approaching the upper frequency.
Once you've established BW, go specify the approximate rise time, using 0.35/(rise time) for 'scopes with Gaussian behavior (simple roll-off). For your digital 'scope, use 0.40 or even a bit more. That's because the filtering in these 'scopes is (and must be) steeper, partly to avoid aliasing above BW-frequency.

Raymond


Chuck Harris <cfharris@...>
 

Hi,

The transient adjustments are never going to result in
a perfectly square waveform from the tunnel diode pulser.

In the first place, no pulser is perfect itself.

Typically, transient response is majorly affected in several
areas. There is a chomp out of the top of the waveform that
is caused by the spacing of the leads leading to the deflection
plates. The interactions are very many.

You can tell what does what by touching various parts of the
circuit with a small piece of metal on a wooden stick... or
use one of the diddle sticks that has a small metal blade.

I find that the more perfect the square edge, the slower the
transient response. You have to leave a little peaking, and
a little ugliness in the top to get the better than 1ns risetime.

-Chuck Harris

Mr. Eric wrote:

Chuck,

When I take the rise time measurement, I'm using the var knob of the volts/div in order to scale the flat top and bottom of the squarewave to the 0% and 100% graticules. I then use the deltaT cursors at the intersection of the 10 and 90. I will give a thanks and shoutout to W2AEW for his videos that teach these things. I've been wondering for half my life on why I would want an uncalibrated volts/div....

So ideally a 2465A should be producing a risetime measure of 1ns and I'm getting 1.09ns. That's unfortunate. Is it possible for this to be calibration or a dying cap in some filter in the front end? I will say that the inside of this scope is pretty clean which was really nice to see...

The only things I have for testing is the Leobodnar 30ps pulser and HP 8656A Signal Generator 0 to 990Mhz that has a calibration sticker from 2013 that says, calibration not required, for reference only =)