Hi,
I'm working to make some replacement A9 boards for the HP 5065A to the
new style schematic.
Will share the Gerber file when done.
The integrator capacitor is a 1986 vintage TRW 5.0ufd 50V 10% .42"DX1.0"L
axial.
Of course it has an HP part number and no manufactures #.
Any guess as to what
Well I hunted up the change pages for the A9.
The cap is polycarbonate, the original A9 was polyester.
If I can't find the polycarbonate I'll look into the PPS.
Cheers,
Corby
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I agree with Bert,
I always remove the battery.
They will cause grief eventually!
Use either in UPS or the separate DC input jack on the rear.
One note, if the battery is removed and the battery charge switch is in
the position to light the front panel lamp you will degrade the stability
of the
Here is an clip from one of the space qualified ones Bob mentioned.
"The RAFS employs classical rubidium gas cell atomic frequency standard
principles. It utilizes a physics package with a discrete isotopic filter
cell for best stability. The relatively large, cool absorption cell
provides excepti
Hi,
I'm cleaning out a BUNCH of modules from HP 5061A/B. See listing on eBay
below.
More lots of other modules to follow in groups that will fit into flat
rate boxes.
If you have specific wants contact me off list!
Cheers,
Corby
https://www.ebay.com/itm/HP5061A-5051B-A7-AC-amplifier-modules-
Paul,
I agree with Bob, the small telecom ones to include the Efratom ones have
a lifetime that is just a guess at this point.
A brand new PRS10 with a warranty and the original owner repair discount
would be a good bet, they do however have lamp assy problems unless that
has been redesigned.
Th
Attila,
I will send you some raw data.
Attached is a combined plot of a recent successful filter installation.
Only 20 to 25% of units will be improved with the filter mod.
Two things to look for.
1- The short term stability at 1 Sec (Allan Deviation) should drop from
the 2X10-12th range down
Joe,
"What is mounted on top of the 10811?"
That is a Clifton Labs Z1 buffer amp.
Still made but by another company.
Mounted on a small right angle bracket that is mounted using the existing
screws on the back of the 10811 adaptor assy.
It's input is connected to the 10Mhz out pins of the
Saw the plot in the June 12 post.
Pretty much limited by the 3816 up to 10K Seconds.
Would be interesting to see a long plot of the two 5065 against each
other!
Cheers,
Corby
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Back in June I picked up the mystery oven assy that turned out to be the
oscillator assy. of an HP 106A.
Since then I have repaired it and another 106B oscillator assy for a
friend.
My oscillators main problem was that one of the inner oven windings was
open.
Just for testing I installed an array
Hi,
I have Seven HP5062C chassis collected over the years.
Not sure how many tubes are installed (I can check) or their condition.
I'm pretty sure most of the quartz oscillators are missing but I see two
sitting by the pile.
Might be a very few modules missing.
Most of the top and bottom covers ar
Happy Birthday EFOS2 Maser!
The EFOS2 active hydrogen Maser at my place just turned 34 years old!
Pretty impressive reliability.
It is an Oscilloquartz Maser, they are now called T4 Science.
I know a guy in Norway that bought the refurbished EFOS3 Maser last
year directly from T4 Science! It is 3
Tim,
The EFOS2 uses an Aluminum cavity! So machining would be easier than
Copper!
The complete manuals with schematics are on Tom's Leapsecond.com site.
Making a homebrew Maser was bandied about a few years ago on TimeNuts.
Cheers,
Corby
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time-nu
"Copper has a quite high temperature expansion, so could you servo
that via the cavity temperature ?"
To answer, both Copper and Aluminum cavities use the temperature setting
to coarse tune the cavity.
Fine tuning is via Varactor diode and modern Masers do servo "Auto-tune"
the cavity to reduce d
Dick,
The AC connector used depends on if the unit is an option 010 or not!
Regular unit MS3106-14S-5S
Option 010 MS3126F14-12S
Service manual PN is 05062-90029
Cheers,
Corby
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I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with th
David,
I would let it set on the peg in Cs off mode for a fewdays.
It can take a long time for some tubes.
An external HV supply can also be tried if it does not come down in a few
days.
If it does come down turn the switch to operate to turn the filaments on.
The ion pump should peg again, th
Hi,
The tiny coil inside the beam path is the low frequency coil used for DC
testing of the tube.
The tube shown is a standard performance tube and has no degaussing coil.
The flat windings on top of the shield are the C-field winding.
The high performance cavity is even "prettier".
You can se
Scott,
If you pull the SMB lamp connector off of the chassis jack you can Ohm
out between the center pin and shield.
Try both polarities of the leads.
If the 1330 Ohm resistor is good you should read around 3330 Ohms.
This is the sum of the 1330 and a 2000 Ohm resistor.
The 12 Ohm (selected) r
Scott,
The resistor should be 12 Ohms nominal, I'd try installing a 12 Ohm and
see what happens.
The lamp should light within 10 seconds or so of applying power.
If you have a spectrum analyzer you can place a loose wire close to the
lamp assy and see the approx 120Mhz signal if it's oscillatin
Paul,
The Zeeman frequency you use depends on what synthesizer frequency your
unit is set for.
Either 48.82Khz or 53.53Khz.
See: https://www.febo.com/pipermail/time-nuts/2008-July/032378.html
The Zeeman coil is close to a short. You set the amplitude to the spot
that gives you the best look at
Well I thought that would get your attention!
It's not quite as simple as that, however it CAN be done.
First you need a good "mini" tube scavenged out of a 5061A/B.
These smaller diameter tubes HP made for 5061A/B replacements
are essentially a 5071A tube with different connectors.
Then you need
Pete,
That is a VERY early unit.
Those early ones did not have the TED device.
I have only seen one unit with an earlier SN!
Ohm the lamp oven windings to the threaded post protruding from the end
of the optical unit. (should be open)
Also check across the oven winding (50 Ohm)
If the windin
Very cool!
Thanks for sharing.
You could probably use any of the large vintage neon bulbs to replace the
missing lamp.
Cheers,
Corby
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Skip,
If you are setting against GPS then you are done.
For most applications either Zeeman frequency- synthesizer setting will
be fine.
What the Zeeman adjust lets you do is set the frequency (via the C-field)
to within the accuracy specs for the instrument without having to use
another referen
Looks like Oscilloquartz is getting ready to sell this commercially!
Will give the 5071A a run for the money!
Reliability should go way up as:
-No electron multiplier
-No ionizer filament
-No state selection magnets
Also all the fiddley bits (laser diodes and photodetectors) are external
to the tu
If you cannot get the ion current below 50ua or so after a week at 5kV
then you are out of luck.
Most likely you have resistive deposits on the ion pump insulator.
If you can get the tube to give a decent SN at those levels then you can
run with the alarm circuit bypassed.
I have run tubes a couple
Things to be careful about!
"I think the final vacuum improvement can be achieved more
quickly if the cesium oven is on."
The outgassing in a tube that has been off for an extended time
is almost all from the oven filaments and the ionizer filament.
The metal surfaces are virtual "sponges" and g
Donald,
I agree with John, remove the gearing gizmo from the 10811 assy. the
adjust hole lines up any way so no need to drill a hole. you just need a
long insulated tuning tool. Also agree that a quick indication of tube
operation can be seen if the beam current rises when the mod is turned
off.
Attached is a PIX showing (CW from top left) the:
>ionizer filament
>Oven filaments (STD oven)
>standard oven assy
>high perm oven assy
The HiPerf oven filament is the sealed spiral wound tube on the face of
the oven.
The posts on the top edge of the ovens is the connection to burn a hole
in the
A friend asked me a while ago why the FTS Cesium tubes were so light.
Since they were designed from the beginning to fit in a 5.25" high
chassis that cut quite a bit of the weight.
However a large amount of weight was saved by using a Ramsey cavity that
was not milled from a massive block of co
Attached is a plot showing the measured floor of the sine wave loop
in the 5061A/B and also in the 5065A, along with plot of an HP 5061B
with a high performance tube.
The tube is the limiting factor.
As you can see the margin provided by the current design is substantial.
Also if you look at t
Hi,
I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long.
I need 20 holes in each end tapped for 4/40 and 1/2" deep.
This is for a Rubidium project.
The local machine shop want's $360.00
Anyone have a machining setup that could do the work a bit cheaper?
If not I'll giv
Well that generated a lot of advice and thanks for it!
I think I might do it myself and go with a 1/2" hole depth and 1/4"
threaded depth.
I'll get some of that Aluminum Tap magic, some new taps and new drill
bits.
Good idea about drilling the end plates first and drilling thru to match.
Between th
Thanks everyone.
Not looking for a redesign, just figuring out how to get the holes
drilled and tapped.
I have come up with a scheme that looks promising and will let you know
how it goes.
The enclosure only has to hold +.1PSI of dry nitrogen without leaking.
It will have a pressure sensor insi
Donald,
HP changed from 12.631771.6 Mhz to 12.631772.5 Mhz in the later days.
The Zeeman frequency changed to correspond from 42.82Khz to 53.53Khz.
The 5071A uses a Zeeman frequency of 39.949Khz.
I believe they liked the stability a bit more at the different C-field
current.
Either way will pu
Donald,
Will look forward to seeing your Allan Deviation plots before and after.
That will be the only way to verify your modification will make any
improvement.
I suspect the improvement at a few seconds will degrade it at other Tau.
Cheers,
Corby
_
Well I did some research and found my new best friend!
If you remember I needed: "I have a square aluminum tube 5" X 5" with a
.25" wall it's 8 1/2" long.
I need 20 holes in each end tapped for 4/40 and 1/2" deep."
This for a Rubidium standard I am working on.
I found all about self forming ta
HP5065A +20V supply and C-field circuit mods
I'm doing some more work on the 5065A and thought I'd share the results
of a
modification (one of several that will be done on this unit).
I measured the +20V P/S temperature coefficient and got -13.5ppm per
degree C.
This equates well with the 1N938
Ulf,
You either should replace the -6010 old style A7 or if building one from
scratch build the late style.
The new style has a BP filter on the 2nd harmonic that makes the 2nd
harmonic reading a better indication.
On the old style as you adjust the CF (in open loop) you will see the 2nd
harmonic
HP5065A C-field mods and optical unit mods
In addition to the power supply mods:
-removed AC components
-power now supplied with an external DC lab grade low noise
highly regulated supply.
-temperature coefficient of +20 Volt supply adjusted to be
below 1PPM/deg C
See: https://www.febo.com/pip
Attached is the schematic of the C-field supply.
Cheers,
Corby___
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Hi,
I have a copy of the retrofit pages that went with the 10544A install for
the HP 5245A.
There were LOTS of these installed in the 5245 series after the original
oscillators started failing.
Give me a day or so to hunt it up and I'll share it.
It has the schematics of the interface board.
C
This link shows the light from a rubidium spectral lamp.
Its appearance is quite similar to the rubidium lamps used in various
rubidium standards.
There can be a slight bluish cast also, especially at low temperatures as
the lamp warms up.
I'm not familiar with the R&S but depending on the desi
The RB-87 isotope used in Rubidium standards is radioactive, but at such
a slight activity level that special procedures and shielding must be
used to measure it. Any chunk of granite, including your fancy kitchen
counters, far "outshines" RB-87 as a radiation source! A garage built
Rubidium stand
I picked up the guts of a Datum 4040A cesium standard on eBay.
I am at the point of wanting to test the Datum C quartz oscillator
that was part of it.
Does anyone know what the power supply voltage is?
There is also a nice 9Ghz SMA packaged Macom RF amp that I'd like to know
the power supp
Hi,
Last time I checked SRS would flat rate a PRS10 repair for $200.00 to an
original owner or $400.00 to a secondary owner.
Swapping in a lamp assy from another unit is problematical as the lamp
temperature parameters are stored in the units memory.
I had a similar problem when swapping in a
The downloaded manuals from SRS don't have the schematics, but if you buy
a paper manual from them you get the schematics. (At least for the PRS10
and SR620)
Corby
Globe Life Insurance
$1* Buys $50,000 Life Insurance. Adults or Children.
Hi Everyone,
A while ago I posted for anyone with a 5065A that had a 2816A prefix
serial number to try and determine the last HP 5065A sold.
Now I'd like to know what the earliest SN anyone has seen.
The current winner is SN 0940-00203.
If anyone knows of an earlier or similar vintage please le
Hi Everyone,
I'm working on a vintage passive Hydrogen maser that is undocumented and
missing a bunch of the electronics.
I am working on getting it up far enough to see if I can get Maser action
and if so will then work on the rest of the electronics.
Tom Van Baak is hosting the blog on his web
Skip,
I do have a manual around here somewhere but it has no schematics.
It's just a basic spec. and info.
The main info is that is composed of a +15VDC linear supply, A 10Mhz
buffer card to deliver 1VRMS into 50 ohms and an FE5650A rubidium
module.
Corby Dawson
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Hi Everyone,
New updates 2 and 3 and PIX2 updates on the Mystery passive maser blog!
http://www.leapsecond.com/maser/
Cheers!
Corby Dawson
57-Year-Old Mom Looks 25
Mom Reveals $5 Wrinkle Trick That Has Angered Doctors!
http://thir
Update 4 of the Mystery Passive Maser Project is now available at:
http://www.leapsecond.com/maser/
Enjoy!
Corby Dawson
60-Year-Old Mom Looks 27
Mom Reveals Free Wrinkle Trick That Has Angered Doctors!
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Hi,
The clock chip is a National MM5313N, it is also the one used in the
digital clock for the HP 5061A.
Schematics were in the update pages for the older manuals and in the
manual for the newer ones.
Corby Dawson
60-Year-Old Mom Look
Paul,
The time scale selection is to match the offset in each particular
receiver section and thus put it on frequency. Once there you can use the
chart to determine offsets from the value you use.
The synthesizer setting by virtue of how its designed does not allow one
digit changes! You have to
When manufacturing the cells for the 5065A receiver package it was not
feasable or cost effective to try and make each cell exactly on
frequency.
With the sythesizer designed the way it was all thay had to do was make
sure that cells would fall within the 0 to +1000X10-10th range. That way
they co
The HP spec for an "end of life" tube is a main peak of 8.5 nanoamp when
measured at the SMA output jack terminated directly into a high impedance
voltmeter. Use the meters input impedance and Ohms law to determine the
current.
However this value is where the tube stability starts to fall below th
Hi,
Here is a post I made years ago on the subject.
There was a typo and a correction post that changed the resistor value to
5 Ohms, it is corrected here also.
First take a look at the leapsecond.com website. Click on various lab
reports and then rb-cells.
You will see pictures of rubidium cell
Hi Folks,
I played with a few of these that came off the cut up board you describe.
The ones I had put out 1PPS ONLY!
Internally they ran at 8.xx Mhz that divided down to the 1 Hz.
I was able to engineer a tiny add-on board using very small 10Mhz
crystals and made them put out 10Mhz.
By the way
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