Parting 5B10N

Nathan Johnson

I have a 5B10N that got smashed by shippers. The front panel(Both metal and
plastic pieces) was destroyed, and the Sec/Div knob was smashed. If anybody
wants any parts from it, they are yours for shipping.
Nathan KK4REY

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Re: Tektronix 468 anomaly - Ideas anyone?


On 18 Apr 2016 08:27:52 -0700, you wrote:

Yes, it was the 466 I was thinking of - non digital storage.
My 466 is a DM44 version. Nice, fast analog storage!

The 468 is ok for repetitive signals, with its cursor measurements etc. However, it has no digital on-screen readout, a maximum sampling rate of 25 MS/s and no equivalent sampling, i.e. real-time only.
No way you'd see a 100 MHz signal digitised on it!

Malcolm, I never liked the word "piggyback" for the DM44. I'll call it "penthouse" from now on!

The 468 does have trigger to sample clock jitter correction though.
Given that, I am not sure why they did not include equivalent time
sampling although the TRW flash ADC they used is limited to about 10
MHz so this would have required a sample and hold to be added which is
how the 2230 works. Maybe there was not enough room although the
addition is pretty minor.

Re: 5k plugins


I built a curve tracer several years ago from a magazine article.Installed 2 triple-banana-jack sets, spaced to fit the Tek adapters.Added a switch to select which jacks to display.Display is X-Y to any scope, but a 7A22 works great for the vertical since I can control the bandwidth to eliminate the noise.
 HankC, Boston WA1HOS

[Non-text portions of this message have been removed]

Re: Tek 2465B readout horizontal stability problem or not ?


Given your low sweep rate of 1ms/div, I suspect that is exactly what
it is.

At certain sweep rates, the sweep can interact with the readout
positioning through thermal effects in the amplifiers. The readout
jitter adjustments correct for this to a certain extent.

On the 7000 mainframes which generally suffer from this more, it gives
the readout (and mainframe) more character and personality.

On Mon, 18 Apr 2016 12:08:06 +0000 (UTC), you wrote:

Hi Albert 
Thank you for your response, I'll watch it all the time if this adjustment solves the problem.

On Monday, April 18, 2016 1:06 PM, "aodiversen@... [TekScopes]" <TekScopes@...> wrote:

  Horizontal readout jitter? Adjustment R805? Mentioned at page 5-15 and Adj Locations 4 of the Tek_2465B_2467B_Service_Manual_w_OCR_and_Schematics.pdf manual. Search for "readout jitter".


Re: TekScopes question


I made an account before the TekScopes group was created over at but it all seems to have worked out correctly.

Now that more of the contents have been transferred over, wow, I had
not realized that I posted so much.

And OMG, the search works. Yahoo, you had one job! What were you

On 18 Apr 2016 01:38:54 -0700, you wrote:

Michael, maybe you didn't Log In yet. The first time you click Log In you can enter your e-mail address and then receive a message with a link that leads you again to Then go to Profile (under "person" icon right-upper corner) and set your password and other things and save these. Then under Your Subscriptions --> Actions you can set e-mail preferences. I didn't try email delivery myself and I don't know whether e-mail delivery is enabled or disabled by the moderator while Yahoo is still in use.


---In TekScopes@..., <2465bct@...> wrote :

I didn't see any way to get an email feed from That is much more
convenient than checking for new messages in a browser. Did I miss something?


The Yahoogroups TekScopes message archive and the membership list have been
transferred to, but this new group will remain on hold until we
decide what to do. You can continue to use the Yahoogroup. I've disabled
posting at for now. We're also not accepting any new members at until (and if) we switch over.
Michael Dunn

Re: Horizontal calibration of a 7704


On Sun, 17 Apr 2016 15:55:31 +0100, you wrote:

My question is can I do it with the time bases I have?
Isn't that what I said?
Yes, but Jerry just has a way with words. :)

Re: Horizontal calibration of a 7704


Before I got a standardizer, I added test points to a single channel
vertical amplifier, a 7A16A in my case, so that I could attach a
voltmeter to the vertical signal outputs into the mainframe. This
allowed me to accurately test and set the mainframe deflection and

I agree with Craig though; since all of your timebases show the same
calibration error, I would just pick one as a reference and adjust the
horizontal deflection based on it and a frequency reference.

I see that there is a single horizontal gain adjustment, R522, on the
horizontal CRT amplifier board shown on schematic 7. You described a
lack(?) of horizontal gain? Maybe R522 is open.

Also check that the beam finder works in the horizontal direction. The
collector of Q514 needs to be at -14.8 volts. If it is higher, then
the horizontal deflection will be lowered.

On 17 Apr 2016 05:23:22 -0700, you wrote:

My 7704 is about .75 of a horizontal division out with all timebases, by which I mean a 7B80, 7B85, and 7B92A. I conclude it is the 7704 itself that needs horinzontal calibration. The manual specifies a procedure involving a calibration fixture as a horizontal plugin and a 7B71 as a vertical plugin, neither of which I have. Is there a way involving what
I do have that won't blow it up? I can see that logically most any timebase would do as a vertical plugin, and any other fixture as a horizontal plugin that would produce the same centred vertical line: my question is as to the practicability.



Re: Tek 2467A X/Y issues

Jeff Randels

Hey that's good to hear Siggi. Crank the CRT up brighter? Ok I am pretty
jealous at work about keeping it dim on our instruments.

I sought out the seller not the other way around. The A B glitching like
you had when I would adjust Sec/Div and had A B pulled convinced grab one.
The Tech at work thought maybe the switch asvit was a bit loose.

I thought going through some checks would be a good idea after the cap
upgrade. I am really happy with the performance after the upgrade other
than XY. But that was/is an unknown anyway

I did deoxit the slider switch. What is IPA?

I am amazed you could tell I had the intensity down. Only from the dialog I
guess as it appeared so bright and fuzzy on the video.

Well I will try brighter tomorrow, see what happens, & post back.

Re: Tek 475: square wave leading corners too rounded?


On Sun, 17 Apr 2016 00:46:02 +0100, you wrote:

On 16/04/2016 05:48, David @DWH [TekScopes] wrote:

I scrounged a BNC-T and 50 ohm terminator and improved my Arduino-based
square-wave generator to emit higher frequencies with less jitter.

For reference, the Gratten GA1042CAL with 250khz input via the BNC-T &
50ohm terminator:

The 475 on Channel 1 at .5 volts/div:

The 475 on Channel 2 at .5 volts/div:

The tilt on Channel 2 varies with attenuator setting. At .2 volts/div
it looks more like Channel 1.

Am I right in thinking this suggests vertical attenuator problems in
both channels, likely either due to dirty/oxidised leaf switch contacts
and/or cold solder joints in the attenuator blocks?
Yes, there is something going on with the attenuators but I doubt the
problem is with the switches or solder joints. An open circuit
usually causes a very high pass filter characteristic but at 250 kHz
that might be difficult to see. It would be helpful to lower the
square wave frequency a lot, like to 1 kHz, so that the DC response is
more evident.

Besides using a lower frequency square wave, the same square wave test
needs to be done at 5mV/div where none of the attenuator sections are
in the circuit. That will verify if the problem is only in the
attenuators. Knocking the 5 volt output from your Arduino down to 20
millivolts can be done with a couple of resistors to make a low
impedance attenuator at the Arduino.
I have done so. The squarewave frequency is now 1.25khz. The crudeness
of my ad-hoc Arduino-based squarewave generator is such that it isn't
(yet) easy to dial up an exact desired frequency; hopefully it's close

For reference, this is the output of the frequency generator on the
Gratten GA1042CAL:

This is Channel 1 on the 475, AC coupled:

This is Channel 2 on the 475, AC coupled:
This is Channel 1 on the 475, DC coupled:

This is Channel 2 on the 475, DC coupled:
Ok, so the tilt we see here is just the AC coupling which is normal.

All are shown with BW limit turned on (set to 20mhz on the 475; on the
Gratten it's just on/off), including on the Gratten, to limit noise
emitted by the Arduino that otherwise makes the traces hairy.

Note that the slow rise of the leading edge of the squarewave plateau is
still present. This is the 475 on Channel 2 at 5 microseconds per
division, demonstrating roughly 20 to 25 microseconds to reach the
nominal plateau:

I believe that slow rise accounts for the obviously rounded leading edge
of the square wave when displayed at .2 milliseconds per division.
And this is a problem.

Viewing the output of the Channel 2 vertical amplifer on the Gratten --
via the BNC connector on the back panel of the 475 -- demonstrates what
appears to be the same slow rise, though it's perhaps not as obvious due
to the graininess of the Gratten display. I presume this localises the
problem to the vertical amplifier rather than the vertical deflection
Unfortunately unlike some other designs, the vertical amplifier
circuitry in this case includes the vertical channel switch which is
what produces the channel 2 vertical output. That might explain why
we see the same "dribble up" on channel 1.

I think on the 465 the high impedance x10 and x100 attenuators are in
little hybrid modules which are installed into collet socket pins. You
can pull them out and reseat them to check that the socket pins are
making a good connection.

I did have one of these hybrid modules with a bad connection inside
where the pin attached. I touched it up with silver solder and it
worked as good as new.
On the 475, the attenuators are hybrid plug-in modules.

I'm not sure what to tackle next. Any suggestions?
I think you did rule out a problem with the vertical CRT deflection

Double check that the "dribble up" occurs on both channels. If so, I
think either they were both miscalibrated in the same way or there is
something going on with vertical channel switch U370 shown on
schematic 3.

I would be a little suspicious of C403. Can you reseat U370? Can you
replace U350? The 7474 IC is pretty common in parts bins.

Also double check that the "dribble up" is not an artifact from your
pulse generator using your Gratten. Examine the falling edge closely
to see if it displays the same thing using both oscilloscopes.

Does the "dribble up" change as the vertical position of the trace is

Note that "dribble up" refers to an actual transmission line
phenomenon at high frequencies which should not be present at 20 MHz
(or 200 MHz) and below. Your measurements using your Gratten rule out
this problem with the test coaxial cable you are using.

Re: PG-502 blowing fuses - PS repair


On 16 Apr 2016 03:03:14 -0700, you wrote:

But doesn't U640 require +12V to be there in the first place ?
It does because +12 volts to pin 12 powers the control circuits in
U640 which is a 723 voltage regulator. But +12 volts is independent
of what the +15 volt regulator is doing. It only depends on fuse

And when I provide the +5V I'll have to enable the +33.5 V branch with the consequence that +15V is going up also which in turn can have other consequences e.g. on the thyristor circuit.
The +15 volt regulator can be deactivated by removing Q600.

That's why I was asking to start the repair "outside" the frame by which I didn't mean an extender but *really" outside.and measure certain branches by supplying the required voltages externally.
What I do is use one of my power supply mainframes, a TM501 but the
others work for this, with the covers removed so I can access the
sides of the plug-in which also has its covers removed.

2430 fix repair or parts

Cuc Tu

I think this one is not a basket case since it will power on, pass POST, and ran the self cal. OK.

It was not used for a few years, but worked fine. It would first lock during POST, then it would complete POST with different failures (WP, CCD, PA), finally it passed all self tests and completed a self cal, but the display goes off after a minute of being on. I have only given it a handful of power cycles to get through this. It will not sweep and just shows a static, full scale repeating sine wave burst. When the sweep time is lowered, I can see a sine wave at each end with the center flat (in case that is characteristic of something).

I have opened the case and found the Lithium battery, which measured 3.67V. It's quite clean inside and no corrosion. That is as far as I went into it. Next I will get to the PS and I plan to just recap it. I have some references to a 2440 with a parts list to check against.

Just wondering if there are any specific things to look for beyond the usual leaky/bulging caps? I did not find the U800 chip often discussed. Does this model use that chip?

Thanks for any guidance here.

Re: Tek 2467A X/Y issues


Hey Jeff,

this, I think, is mostly working as intended. Possibly the CRT adjustment
procedure would allow the X/Y display to show a fraction brighter. I just
tried this on my 2467, and I get the same exact thing.
What you need to do is to (carefully) crank up the intensity after you
toggle to X/Y mode.
This is happening because the 2467s jealously guard against CRT burn-in,
and the CPU/MPU is simply turning down the beam current/intensity when you
click over to X/Y mode.

There's no way this has to do with the front panel switches, and whoever
indicated this might be the case has sold you a packet. The 2400-series is
all drive-by-wire, meaning that most all of the scope is controlled by the
MPU, which takes input from the front panel switches.
Incidentally, my 2467 had terrible glitching on the front panel switches,
but they cleaned up nicely by teasing some IPA in there and giving them a
good workout. I may also have given them a squirt or three of DeOxit D5 - I
don't remember.

BTW: Jeff's video link is here <>.


On Mon, 18 Apr 2016 at 22:52 Huzzunga.Din@... [TekScopes] <
TekScopes@...> wrote:

I have gone through all the boards with a cap upgrade, and there is a 100%
improvement in the scopes lowered intensity & sharper focus.

What started all this was the scopes inability to present, and then hold
an X/Y display. The scope would hold the 45 degree display for about 1/4 of
a second. It is about the same. I think I imagined it longer in the video.
The X/Y jumpers are in the outlined X Y locations.

I cleaned the Hybrid IC, and I am down to thinking the Sec/Div control.
While I had the scope apart for the A 1/ A 5 boards I separated the control
panel modules from the panel face. I took the Sec/Div control switch apart
noticed the inline switch that rides the Sec/Div cam like, had 3 terminals.
One terminal leg was cut off, and only the other 2 soldered in the board.
Likely an OFF/ON/OFF switch.

I have the Service Manual via download, waiting the arrival of the real
thing. It is a lot better than nothing, but not fully functional as I am
used to in these type of docs.

Because I was able to see the Sec/Div control to drive this in-line
switch, it seems mechanically that is okay, the tan plastic moves the
inline switch. This brings up a couple of questions in my mind.

1. Is it normal to see a 3 position switch with a lead cut of used in
original installations?

2. Is it normal to see a 3 position position switch with a lead cut off in
repair situations?

I think this switch is the heart of my X/Y problem. It is not holding ON
position, so my X/Y falls off. Makes sense to me, but I'm just a self
taught solder slinger.

If you want to see it happen, or have a laugh, there is a YouTube video on
my channel Huzzunga.

One more symptom I was unable to duplicate is when the switch is flipped,
and I am driving to stop the trace to display X/Y, after it does the
momentary X/Y thing sometimes turning the control back CW will flash all
the panel LED lights as opposed to begin driving the trace faster again.
If that symptom rings a bell for someone let me know.

I would rather buy an in-line switch, and replace it first, rather than
purchase a 70 something dollar used panel from eBay.

The symptoms again;
The scope displays X/Y momentarily, and sometimes after attempting an X/Y
display all the control panel LED lights will flash as the Sec/Div control
is turned Clock Wise.
If you have a part number on the Off/On/Off switch let me know. If it
sin't controls it starts getting harder to find. Or an IC.
Thank you for your time

Re: 5441 High Voltage

Nathan Johnson

I'll let you know on that, pending some 300ma fuses to test, not something I seem to be able to get locally.
Nathan KK4REY

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On Tue, Apr 19, 2016 at 16:14, kurt.harlem@... [TekScopes] <TekScopes@...> wrote:
If you lift the base of Q410, does the fuse still blow?

[Non-text portions of this message have been removed]

Re: 5441 High Voltage

Kurt Rosenfeld

If you lift the base of Q410, does the fuse still blow?

Just Joined

Cuc Tu

Hi All,

I'm the proud owner of a 2430 and 496. Both were my grandfather's and I've had them since his passing about 7 years ago, but we both used them when we had occasion to do so. The 2430 now has a problem after not being used for a couple years. I'll make a new topic just for this attempted repair. Also, the 496 has an intermittent phase lock error. Me, I'm jut a hobbyist technician with some experience in RF and microwave.

5441 High Voltage

Nathan Johnson

Working on a 5441, blown HV fuse. Transistor is good, so I'm suspecting one
of the HV diodes(CR412) and the multiplier(U410).
There really isn't a good way to test these diodes is there? Pretty much
need to replace and try that? Anybody have a modern 12kv/10ma diode they
For the multiplier, if it is toast, I should see a measurable short from
either the input or output to ground?
Thanks for any suggestions!
Nathan KK4REY
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Does anybody have the Tek hardware catalog that covers knobs?


Like for semiconductors, there was an internal Tek part number catalog for knobs, which I really need to try and correctly number the knobs on our site. knobs have no number on them, and many look similar, but have minor differences, making it very hard to identify some of these parts correctly. it is currently driving me crazy as I try and clean up our stock after the floor repairs and restoration (9 months of hell).

I have many other Tek internal parts catalogs, but not this one. I have also never seen the Tek CRT catalog, if it exists. I would really like to see that too.

any help greatly appreciated,
all the best,
walter (walter2 -at-
sphere research corp.

Re: FS: AM503 current probe amps


On 4/19/2016 4:29 PM, jerry@... [TekScopes] wrote:
No, without the probe. I was told they worked but without a probe I
can't test them. They look to be in good shape.

I kicked around buying a probe but they are expensive.

Thanks Jerry

At $30 I susupected as much

I will pass


Re: FS: AM503 current probe amps


No, without the probe. I was told they worked but without a probe I can't test them. They look to be in good shape.

I kicked around buying a probe but they are expensive.

Re: FS: AM503 current probe amps



Does that include the probe and do they work?


On 4/19/2016 3:34 PM, jerry@... [TekScopes] wrote:
I have two AM503 current probe amps that were included in a frame I
bought. They look to be in decent shape. One has a broken pull-tab and
the second has a cracked plastic bevel corner. I would like $30 per plus
shipping. I've been kicking around the idea of gutting them and using
them as modules for other projects as I don't have a need for them. Send
a PM if interested.