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I have a defective 70900B local oscilator plug-in module.
Cannot find proper documentation to start repair.

To get my 70000 SA working again, can I swop the 70900B out for an older gen 70900A ?

Any suggestions are welcome.

Add to this a fourth metric; phase noise.

You won't be doing yourself any favor if the frequency reference you use in your shop is noisy.? Of course, you'll need to have some equipment capable of measuring said noise, as well as a less noisy reference to use in those comparisons.

There's a reason one who pursues the most favorable characteristics in all of these metrics is called a "Time Nut"... it is never-ending; the deeper one dives into learning and striving for accuracy and precision, the farther down one finds the bottom of the hole.

?

On Sat, Jun 15, 2024 at 11:26 AM, Maciej Kawalkowski wrote:

All good feedback from everyone. thank you.

Boards arriving 6/20/2024

Hi Guys,

I am starting to look at the 180 oscilloscope series. I bought a 180A and a 181A mainframes, a 1825A time base and a 1806A differential vertical amp.?

I could order the 180A and 1825A manuals to Artek, but I am not able to find that of the 1806A.

Have someone please the 1806a manual?

Thanks

There are two or three parts to "optimal" in the lab frequency reference context. The first is that if all gear uses the same reference, then they all will agree within +/- one count of whatever units are measured, typically to 1 Hz resolution for counters, generators, and spectrum analyzers and such. This is regardless of absolute frequency precision. If each piece has its own internal reference, any differences in measurements will include the differences in references. A common reference for all conveniently eliminates these differences. Most "regular" gear won't notice these details. It shows when making high resolution measurements, or when frequencies are multiplied up by large factors, say, in communications gear.

The second is the absolute precision at any point in time, depending on the reference source quality. The third is the stability, over various time frames. These usually go hand in hand - the best references have very high precision and stability, and the never-ending pursuit of improvement and perfection.

Ed

I have one of these inexpensive units running to send 10MHZ to all my devices.

Since the GPSDO runs on 12v it can be used with portable gear. Takes about 3 mins to lock from cold.

https://brisbaneradiosociety.net/10-mhz-reference-by-vk4amg/

In my case, I don't bother with a common reference piped around all my test gear. I usually rely on the various OCXO references in my test gear. I do check and adjust them every year or two.

However, I do sometimes connect the reference from one (vector) sig gen to another if I want to vary the phase of one output compared to the other.

There is also a risk that an external reference can add spurious terms or it can add jitter and degrade the noise performance. It can also be quite a complicated thing to set up because you would want the reference to distribute reliably even when some bits of test gear are powered off. I just don't see much advantage to having a common frequency reference.

However, some people will run a GPSDO 24/7 and pipe it around their workroom using a suitable distribution amplifier. I like to turn everything off when I finish in my workroom so this isn't a realistic option for me anyway.

I'm not a time nut, so take this with a bit of salt.

You're dealing with two things here in measurement, stability and accuracy.

Accuracy you can get easily enough by a GPS, or even Rubidium, and in the short term, OCXO.? This answers the "how close is that to 10 Mhz" question.? I suspect that it means most with uncoupled test equipment not locked to a lab standard, or portable equipment where locking is not possible.

Most portable stuff will be OCXO if that.

Stability is another matter.? Various sources can be made on frequency, but then how long do they stay there?? Depends on the reference.

Do you need this?? Depends on the measurement, IMHO.? If you have multiple counters in the lab, then the best thing is to lock them to a source, if you can.? Not all will.

If you do a lot of portable work, you pays your money and you takes your chances.

If you are specifically interested in long term stability, or accuracy, then you've answered your own question.

Then again, there's the pursuit of accuracy for the sake of accuracy


Harvey

Guys,

I've heard people say that having a totally accurate external frequency reference available and distributed to all the test devices on one's test bench which can accept it is an optimal solution. But what is it an optimal solution to? What's the advantage of such a system? I've heard various absolute standards mentioned over the years. Currently GPS satellites seem to be in, but I've heard such-and-such a radio station being recommended as well. What's it all about?

J.

Hello Yves_Tardif,
unfortunately my initial answer bounced from the email address you sent me your program.
Thanks for your program. The 5350B is really a weird beast!
I made some initial tests on friday following your instructions. At first not working. Had to remove checkmark in Keysight Communicator -> Settings -> "Enable Keysight GPIB cards for 488 programs". Now it worked, but some measurements showed "0".

Over the weekend I was busy with other obligations. So I tried again today with no success. Hitting "Stop" did not work so I could not select Input 2.
Input 1 not working because of fried sampler. This was the reason the counter was donated to me.

Regards Ernst?

Hello there!

Just bought a few plugins and another mainframe for 8660 system. One of the plugins have coax and normal pins missing in the conector and want to repair it.

There is a chance to know type and part number or a vendor who sell them (new or used)??

Best regards,
Ruben

Keith Hallman has a large selection of Capacitor catalogs & data sheets with some Engineering Bulletins:
... scroll down, past the various Cat. cover photos.
( extensive & very helpful, ... but some Engineering & Technical Bulletins missing? ):



-- Anyone know of other extensive component catalog collections ?

Hi Richard,

Alas, I think you may have learned the wrong lesson.

The proper lesson, IMHO, is don't connect the 410B's
AC ground clips to anything but a locally grounded,
chassis ground.

It's been a long time since I explored these meters,
and their problems, but there are some serious safety
issues, in my opinion.

The 410C is safer than the 410B, but in both, HP punted
on safety in my opinion.

Ordinarily, the 410's, in DC modes, have the guts of the
meter floating relative to the case. That means you can
get away with hooking the "common" lead to 400V relative
to ground, and still be safe.

AC wrecks all of that.

When the meter is put into the AC mode, the common lead
becomes connected to chassis ground, in preparation for
the grounded AC probe, and its body.

This can cause quite a surprise if you have the common
lead connected to something that is elevated from chassis
ground, as poof your meter's switch burns up.

At least with the "C" model, you can unplug the AC probe,
but you still can't solve the AC function position issue.

-Chuck Harris


On Tue, 18 Jun 2024 08:01:33 -0700 "Richard Knoppow"
<dickburk@...> wrote:

Well, you answered my question, namely how hot do the probes get.
The EA35 draws slightly more power than the 2-01C but both are close
to 2 Watts so probably probes with either will feel the same. I
wanted to make sure the correct voltage setting for the EA34 was 6.3
Volts and evidently it is.
The handbook is full of warnings about the meter chassis and
ground connections going to power line ground. I have a 3 to 2
adapter on the power plug to mine. Actually, I learned about this
problem long ago when my main mentor blew his 410B up by grounding
something.

On 6/18/2024 6:51 AM, Chuck Harris wrote:

P = I x E

6.3V x 0.3A = 1.9W

The probe's body provides a bit of heat sinking, but the 2W has
to go somewhere.

Cradle your hand around a 2W resistor running full power, and
get back to me ;-)

Heat is the main reason why 410C's are always missing their AC
probes. The probe gets uncomfortably hot, so it gets removed
and stored in a safe place when it not being used.... never to
be found again.

The other reason the probes get removed and lost is they are
practically useless for everyday measurements. The probe body
is also the probe's grounded return lead. It isn't safe to
willy-nilly ground AC power circuits, as you have to do to use
this probe.

-Chuck Harris

Well, you answered my question, namely how hot do the probes get. The EA35 draws slightly more power than the 2-01C but both are close to 2 Watts so probably probes with either will feel the same. I wanted to make sure the correct voltage setting for the EA34 was 6.3 Volts and evidently it is.
The handbook is full of warnings about the meter chassis and ground connections going to power line ground. I have a 3 to 2 adapter on the power plug to mine. Actually, I learned about this problem long ago when my main mentor blew his 410B up by grounding something.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

P = I x E

6.3V x 0.3A = 1.9W

The probe's body provides a bit of heat sinking, but the 2W has
to go somewhere.

Cradle your hand around a 2W resistor running full power, and
get back to me ;-)

Heat is the main reason why 410C's are always missing their AC
probes. The probe gets uncomfortably hot, so it gets removed
and stored in a safe place when it not being used.... never to
be found again.

The other reason the probes get removed and lost is they are
practically useless for everyday measurements. The probe body
is also the probe's grounded return lead. It isn't safe to
willy-nilly ground AC power circuits, as you have to do to use
this probe.

-Chuck Harris


On Mon, 17 Jun 2024 21:03:32 -0700 "Richard Knoppow"
<dickburk@...> wrote:

I posted before about the heater voltage for the two different RF
rectifier diodes and noted that indirectly heated tubes are supposed
to be run close to the specified voltage. I note that this isn't
always true, V-2, the input DC amplifier of the 410B being an
example. this tube is run at about 4.5 VAC. I think the reason is to
reduce contact potential. V-2 seems to be very sensitive to being
gassy. The instruction book describes how to choose tubes with
minimum gas. I think the low heater voltage has the purpose of
reducing the effect of gas on contact potential. This same trick is
used frequently on 6H6 and 6AL5 tubes used as detectors and noise
limiters to reduce induced hum. My original question had to do with
the heater voltage for the EA-53. The handbook and the data sheet for
this tube specify 6.3 volts where the earlier Eimac 2-01C specifies 5
VAC. My 410-B has the Amperex EA-53 in it. The heater had been set at
about 5.5 VAC so I reset it to 6.3 Volts. Did not seem to make a
difference but the probe gets rather hot. I wonder if this is normal.
It gets quite warm at 5 Volts and my memory of other 410B probes is
that they run hot. Please comment. I find nothing in the material at
-hp- Archive pertaining to this. I am assuming 6.3 V is correct and
will leave it there unless someone has definite contrary information.
The calibration seems very accurate. This thing is an ancient war
horse but its a favorite and I have put a fair amount of work into
it. Mine is a very early version with a smooth-edged front panel.

Also, Sprague put out a series of what were called "Service Sheets" or something similar that went into detail on the performance of various series of their capacitors - they are very scarce and it would be wonderful if anyone that has any would upload them to the group.

I uploaded several Sprague catalogues that have a limited amount of information on various models:

/g/HP-Agilent-Keysight-equipment/files/Components%20&%20Connector%20Catalogues

Also covering Sprague as well as other manufactures are the Radio's Master series:



Hal

I posted before about the heater voltage for the two different RF rectifier diodes and noted that indirectly heated tubes are supposed to be run close to the specified voltage. I note that this isn't always true, V-2, the input DC amplifier of the 410B being an example. this tube is run at about 4.5 VAC. I think the reason is to reduce contact potential. V-2 seems to be very sensitive to being gassy. The instruction book describes how to choose tubes with minimum gas. I think the low heater voltage has the purpose of reducing the effect of gas on contact potential. This same trick is used frequently on 6H6 and 6AL5 tubes used as detectors and noise limiters to reduce induced hum.
My original question had to do with the heater voltage for the EA-53. The handbook and the data sheet for this tube specify 6.3 volts where the earlier Eimac 2-01C specifies 5 VAC. My 410-B has the Amperex EA-53 in it. The heater had been set at about 5.5 VAC so I reset it to 6.3 Volts. Did not seem to make a difference but the probe gets rather hot. I wonder if this is normal. It gets quite warm at 5 Volts and my memory of other 410B probes is that they run hot. Please comment. I find nothing in the material at -hp- Archive pertaining to this. I am assuming 6.3 V is correct and will leave it there unless someone has definite contrary information. The calibration seems very accurate.
This thing is an ancient war horse but its a favorite and I have put a fair amount of work into it. Mine is a very early version with a smooth-edged front panel.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

my goof:

most likely: Tantalum glass sealed (dry ?) ?(? Not:? steel, silver, Aluminum ? ) Axial capacitors,?