Date   

Re: PTB 100 Ball Efratom

stevenhorii
 

Chuck and Rick,

A link on posts from Corby Dawson on the leapsecond.com page regarding his
tweaks to the HP 5065 standard:

http://leapsecond.com/corby/Super-5065A-Project.pdf

and Corby Dawson's page on EH Scott Radio Enthusiasts:

https://ehscott.ning.com/profiles/profile/show?id=CorbyDawson&

The EH Scott Radio site is dedicated to, as the name suggests, EH Scott
Radios.

As Chuck suggests, join the Tinenuts list on leapsecond.com (allows you to
get updates and post questions/comments)

Steve H

On Tue, Jul 14, 2020 at 11:08 AM Chuck Harris <cfharris@...> wrote:

join timenuts, and look in their archives.

-Chuck Harris

garp66 wrote:
hi Chuck, Steven,

Where can one find Corby Dawson's detailed procedures and info ?
Any .pdf's research or technical papers, or Blogs ?

For both the Rb cell Rejuvenation & the Optical mods to the HP 5065a ?

thank you,
rick






Re: Calibrators vs Signal/Function Generators

Stephen
 

The time base is IMHO, the most important thing that has to be accurate in a scope. You don’t use it to accurately measure amplitude, you have a DMM for that. So I personally use a TEK 184 to calibrate the time bases of all my scopes. And using the Delayed Time Base method, I can calculate a random frequency from my Function Generator down to about 0.1%, by eye, and sometimes less. That’s good enough for me. When I tried to calibrate a scope with a regular function gen, I was Way off, and by a lot more.
FWIW


Re: Tektronix 2230

satbeginner
 

Hello Saroj,

how disturbing it must be for you to repair this one.... :-(

One thing I can think of is the following:

Would it be possible to run the scope again from your external 43VDC, while measure the current at that point?
The document Hakan wrote says the expected current into the secondary power supply should be around 1,5 - 2 Amp.

If in your case the current is (much) higher, you might start looking in the secondary part first, before trying the primary power supply again :-(

I will try to think of other approaches towards a real solution.

Hang in there,

Leo


Re: Tektronix 2465b Boo Boo

squirrel@...
 

Hi Tom I searched through the hundreds of read me notes that I stick all over the place and it appears that I did make an adjustment to the vertical centering pots.
This was several months ago and it slipped my mind but It has all come back to me now so let me clear some things up.
The reason I did this was because the centering was way off but it has got progressively worse.
I have ordered a Full Cap kit from Myach and will do this when it arrives.
It also appears that U400 has gone because of huge vertical scale compression.
So my next question is where is the best place to by a U400 I see them ebay but is this risky .
Exercise 05 hrs on 19701 pwr on/off 1721
I also would obviously like to replace the Dallas I have a burner that I can use.
I manually wrote down all the data from Exercise 02 I notice that some of the data lines end with a X would these data lines be the one's that fail the cal test.
And if so can they be identified or married to there cal no

00 20b8
01 060e
02 064a
03 063d
04 2642
05 064c
06 25e7
07 061f
08 060e
09 261d
0a 064c
0b 028d
0c 227a
0d 027b
0e 2000
0f 2000
10 2289
11 027d
12 227c
13 027d
14 0293
15 2077
16 0020
17 0020
18 201e
19 201e
1a 1cb8
1b 3d2e
1c 1d68
1d 1d13
1e ifac
1f 3fab
20 3fa7
21 1faa
22 3fb6
23 022d
24 222c
25 2229
26 222a
27 3d0a
28 3e14
29 1d52
2a 1000
2b 1fb2
2c 1fac
2d 3fa7
2e 3fa9
2f 1fb9
30 22e0
31 02e1
32 02de
33 22df
34 083f
35 2849
36 2823
37 2843
38 0835
39 083f
3a 0830
3b 205f
3c 0865
3d 283e
3e 085c
3f 084e
40 0859
41 284a
42 205c
43 2341
44 032f
45 2330
46 0676
47 2663
48 067a
49 066d
4a 22bf
4b 02c6
4c 1825
4d 0e90
4e 0ec3
4f 2702
50 2704
51 01eb
52 222a
53 2175
54 2173
55 2556
56 05e9
57 0594
58 23c9
59 0558
5a 2431
5b 2337
5c 04a0
5d 2382
5e 22b3
5f 0346
60 0448
61 24e5
62 0427
63 2382
64 03b5
65 03b0
66 0313
67 035e
68 0375
69 22d0
6a 2303
6b 22ba
6c 00ba
6d 00bc
6e 20ac
6f 07e8
70 282a
71 2009
72 3fa8
73 1ce8
74 1ccf
75 00c7
76 00fd
77 00d7 X
78 00ff x
79 006f x
7a d2ff x
7b fae0
7c 01ff
7d ff8b x
7e 04ff
7f ff5c x
80 11fe
81 fda9
82 a277 x
83 ff99 x
84 00ef
85 ff23
86 60fd x
87 fd00
88 20f1 x
89 fde0 x
8a 017f x
8b ff14 x
8c 00ff x
8d ff13
8e 4bf7 x
8f ff77 x
90 8fff x
91 ff48 x
92 22ff x
93 bfcf x
94 21ff x
95 ffc8
96 91df
97 fd34 x
98 fdef x
99 fd83 x
9a 14ef
9b ff03 x
9c 09fd
9d 7e0e x
93 c3fe
9f f700
a0 12ef
a1 5b70
a2 04e0 x
a3 ffdc
a4 b06f x
a5 6f14
a6 8a7f
a7 ef57 x
a8 c3f1
a9 7f00 x
aa 2500
ab 0bd8
ac 2d34
ad 0d60
ae 2d58
af 2d4c
b0 0d44
b1 2d38
b2 2d38
b3 0d30
b4 2d34
b5 0d3c
b6 0d50
bf 2d34
b8 0d18
b9 0d14
ba 100a
bb 100a
bc 100a
bd 100a
be 100a
bf 11c2
c0 0d24
c1 2bc8
c2 0b06
c3 2a88
c4 2a56
c5 0a3e
c6 2a2e
c7 0a2c
c8 2a2e
c9 2a2e
ca 0a34
cb 0a34
cc 2a30
cd 0a32
ce 0bb8
cf 0bb8
d0 0bb8
d1 0bb8
d2 0bb8
d3 2ed6
d4 2eda
d5 0ed2
d6 0eca
d7 0eca
d8 2eb6
d9 2e9e
da 0e66
db 2db6
dc 0c9e
dd 0c9e
de 2fff
df 1d4c
e0 1f8b
e1 1cb4
e2 1cee
e3 1cda x
e4 a0a0
e5 a0a0
e6 a0a0
e7 a0a0
e8 a0a0
e9 a0a0
ea a0a0
eb a0a0
ec a0a0
ed a0a0
ee a0a0
ef a0a0
f0 a0a0
f1 a0a0
f2 a0a0
f3 a0a0
f4 a0a0
f5 a0a0
f6 a0a0
f7 a0a0
f8 a0a0
f9 a0a0
fa a0a0
fb a0a0
fc a0a0
fd a0a0
fe a0a0
ff 0000 x


Re: 2465 Project, story so far.

 

Awesome, thank you for this info, I have managed to dig out a couple of 27128 Eproms so will be able to load the binaries onto these and preserve the originals (just in case).
Just need to find a eprom copier to plug them into.
I will keep you informed if they work, thanks again for your help.


John Carter


Re: PTB 100 Ball Efratom

Chuck Harris
 

join timenuts, and look in their archives.

-Chuck Harris

garp66 wrote:

hi Chuck, Steven,

Where can one find Corby Dawson's detailed procedures and info ?
Any .pdf's research or technical papers, or Blogs ?

For both the Rb cell Rejuvenation & the Optical mods to the HP 5065a ?

thank you,
rick




Re: Calibrators vs Signal/Function Generators

Chuck Harris
 

If you use a function generator, at the very minimum, you will have
to use it in conjunction with an accurate frequency counter, and an
accurate level meter of some sort... say an AC True RMS voltmeter.

Tektronix made their calibration equipment easy to calibrate to
national standards. For instance, their voltage calibrator PG506,
uses very, very low impedance transistor switches to switch a zener
derived DC reference voltage on and off to make a square wave.

Because of this topology, the PG506 can be calibrated by setting
its low impedance switch to ON, and measuring the DC voltage output
of each output voltage position.

The switch's resistance is a tiny, tiny fraction of the 1M input
impedance of the scope, so as to be a part per million, or so, which
is insignificant.

Your function generator is built in an entirely different direction,
and cannot be calibrated to this sort of accuracy... so it will need
to be measured. Most AC meters aren't anywhere near this accurate,
either... or, if they are, it is only at one frequency... likely 60Hz.

You can do what you want, but it will be slow, tedious, and error prone,
and when you are done, it won't be as accurate as your AC voltmeter..

For timing measurements, amplitude isn't important, but a very fast
rise time pulse is, so small errors in where you line up the graticule
on the pulse will be insignificant. The square wave output of most
function generators is not even close to fast enough... And can in
no way make high enough frequency signals to align the higher time base
speeds. An RF synthesizer can, but it makes a sine wave, which is
hard to line up on the graticule, and to make adjustments for linearity
of the sweep...

Your time ought to be worth something. If you have a "pile of scopes"
that you will be looking to calibrate, then you ought to either hire it
out, or get the proper equipment to do the job effectively.

-Chuck Harris

David Berlind wrote:

Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David




Re: Calibrators vs Signal/Function Generators

Dave Daniel
 

Yes. That’s my point.

Suppose one uses a Tektronix SG-504 to calibrate a ‘scope. But how does one know that the SG-504 is properly calibrated?

DabeD

On Jul 14, 2020, at 10:51, David Berlind <david@...> wrote:

DaveD,

But wouldn't you have the "standard" problem in both cases? (calibrator vs Signal generator)

On July 14, 2020 10:35:04 AM "Dave Daniel" <kc0wjn@...> wrote:

Dave,

DescriptionDescriptionQuis custodiet ipsos custodes?

On what basis is a “well calibrated” instrument calibrated? How accurate and with what precision was it calibrated? Against what standards?

The problem is that the calibration instruments, or the instruments used to calibrate the instruments, etc., etc., need to be pretty much dead-on wrt to the actual values being measured. Metrology labs and other people who offer calibration services calibrate their calibration instruments such that they are traceable back to a root source, such as NIST.

I try and keep one indepentably calibrated ‘scope (my 2465B) around for measurement comparison. But then there is my 8566B, my 3456A, and my 8660D which have are uncalibrated.

DaveD

On Jul 14, 2020, at 10:13, David Berlind <david@...> wrote:

Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David





Re: Calibrators vs Signal/Function Generators

David Berlind
 

DaveD,

But wouldn't you have the "standard" problem in both cases? (calibrator vs Signal generator)

On July 14, 2020 10:35:04 AM "Dave Daniel" <kc0wjn@...> wrote:

Dave,

DescriptionDescriptionQuis custodiet ipsos custodes?

On what basis is a “well calibrated” instrument calibrated? How accurate and with what precision was it calibrated? Against what standards?

The problem is that the calibration instruments, or the instruments used to calibrate the instruments, etc., etc., need to be pretty much dead-on wrt to the actual values being measured. Metrology labs and other people who offer calibration services calibrate their calibration instruments such that they are traceable back to a root source, such as NIST.

I try and keep one indepentably calibrated ‘scope (my 2465B) around for measurement comparison. But then there is my 8566B, my 3456A, and my 8660D which have are uncalibrated.

DaveD

On Jul 14, 2020, at 10:13, David Berlind <david@...> wrote:

Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David



Re: PTB 100 Ball Efratom

garp66
 

hi Chuck, Steven,

Where can one find Corby Dawson's detailed procedures and info ?
Any .pdf's research or technical papers, or Blogs ?

For both the Rb cell Rejuvenation & the Optical mods to the HP 5065a ?

thank you,
rick


Re: Tektronix 2246 flickering screen, ch2 not working.

tekscopegroup@...
 

Usually slight waveform flicker seen on these scopes (2245, 46, 47A, 52) is normal as the display is multiplexed.


Re: Calibrators vs Signal/Function Generators

Harvey White
 

Typically:

Frequency is crystal controlled.

Risetimes are held to a particular spec (see PG506, 1 ns or so rise and fall times on certain waveforms).

Amplitudes are in the same sequence as the scope gain control, making it easier to check calibration.

Amplitudes do not have to be readjusted per run, they're fixed by the generator calibration while the function generator (some of them) are variable.  Also note that the PG506 can put out high amplitude square waves while many function generators do not.

Timebases?

Ditto on crystal controlled.

ditto on frequencies.

Now for frequency standards, a CPLD or FPGA would work fine with a known frequency for the timebase generator.  You could make that and possibly use a pre-built demo board.  Amplitude?  you're on your own.

Oh, and some of the cal generators, say the 5000 series, can be remote controlled and therefore lend themselves to automated testing and calibration.

Harvey

On 7/14/2020 10:13 AM, David Berlind wrote:
Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David



Re: Calibrators vs Signal/Function Generators

Dave Daniel
 

Dave,

DescriptionDescriptionQuis custodiet ipsos custodes?

On what basis is a “well calibrated” instrument calibrated? How accurate and with what precision was it calibrated? Against what standards?

The problem is that the calibration instruments, or the instruments used to calibrate the instruments, etc., etc., need to be pretty much dead-on wrt to the actual values being measured. Metrology labs and other people who offer calibration services calibrate their calibration instruments such that they are traceable back to a root source, such as NIST.

I try and keep one indepentably calibrated ‘scope (my 2465B) around for measurement comparison. But then there is my 8566B, my 3456A, and my 8660D which have are uncalibrated.

DaveD

On Jul 14, 2020, at 10:13, David Berlind <david@...> wrote:

Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David



Re: Calibrators vs Signal/Function Generators

Stephen
 

On Tue, Jul 14, 2020 at 03:13 AM, David Berlind wrote:


Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point
as a part of their resurrection. I see that the primary function of some Tek
calibration fixtures is to generate square and sine waves. How is this
significantly different from what a well-calibrated signal/function generator
can do?

Thank you.

David
I’m nowhere close to a metrologist expert,
But I believe that if your generator has a very fast rise time and a very steady and true output signal, that’ll do the job just fine. As a matter of fact, I think that modern gear, when well calibrated to start with, are probably at least as good, if not better, than the older gear from the 60’s or 70’s, which themselves may need to be recalibrated. Provided they can do the same things required in the procedure, that is.


Calibrators vs Signal/Function Generators

David Berlind
 

Question for the hive:

I have a pile of scopes here that I'll be looking to calibrate at some point as a part of their resurrection. I see that the primary function of some Tek calibration fixtures is to generate square and sine waves. How is this significantly different from what a well-calibrated signal/function generator can do?

Thank you.

David


Re: Detailed instructions for removal/replacement of U800 in 2465B

tek_547
 

Thanx John (and Hakan), hopefully never needed ;-)
René


Re: Tektronix 2230

Saroj Pradhan
 

Hi satbeginner
Put on the scope. It survived for 15minutes.And took away of course q9070,
precious for me MUR460, CR901, CR904 and fuse. I am totally messed up with
this oscilloscope.
Where to check, I do not know.
I red some where, higher oscillation of tl594, in my case tl494 causes this
kind of issue. I had measured the frequency with external supply across
C925 and it was 56kHz which is within the frequency specified in the
manual.
Thanks
Saroj

On Mon, Jul 13, 2020, 4:00 PM Saroj Pradhan via groups.io <sarojman.Pradhan=
gmail.com@groups.io> wrote:

Hi Satbeginner
Thank you so much.
Just now, I put the transformer in the circuit. It power on the
oscilloscope, the input voltage to the inverter is 41.8v,may be that is
because of some imperfection in the transformer winding. Also put the Mur
460 in place adding thin wire in the terminals.
Right now, I cannot power on the oscilloscope long because the adhesive
needs many hours to care, so I put it off.
I will report here what happens when the oscilloscope is continously on.
Thanks
Saroj


On Mon, Jul 13, 2020, 3:16 PM satbeginner <@satbeginner>
wrote:

Hi Saroj,

I took the liberty of creating an album:

https://groups.io/g/TekScopes/album?id=250384

regards,

Leo







Re: PTB 100 Ball Efratom

Jim Ford
 

Yeah, Chuck, I read that somewhere, that it's possible to rejuvenate a Rb lamp with heat. I'm hoping to get a spent Symetricomm (a more recent name of Ball Efratom, I understand) unit from Raytheon (Technologies it is now), my employer. Trouble is, it's buried inside a rack and not easy to get at. We cobbled up another Rb frequency standard of about the same age, so it may bite the dust soon, too. I'd take either or both and heat to drive the rubidium off the glass. I need a frequency standard with long term stability for holdover if my Leo Bodnar GPSDO drops out or something happens to the GPS. No, I'm not a time nut, not yet, anyway.

Jim Ford

------ Original Message ------
From: "Chuck Harris" <cfharris@...>
To: TekScopes@groups.io
Sent: 7/13/2020 10:35:43 AM
Subject: Re: [TekScopes] PTB 100 Ball Efratom

I don't think Rb depletion is quite correct.

What I, and others, have found on units that just
ran out of steam, is generally that the RF excited
Rb vapor lamp has plated out its Rb metal on the
envelope of the lamp, seriously reducing the intensity
of the emitted light.

The cure is to re-vaporize the Rb metal off of the
lamp's glass bulb.

To do this, take the Rb lamp assembly apart, and you
will generally see the lamp's envelope is black in
appearance. Heat it with a hot air gun and at a
certain temperature, you will see the black coating
simply disappear.

The Rb lamp is ready to go another decade or so.

-Chuck Harris

stevenhorii wrote:
I can’t tell you about phase noise, but a key feature of rubidium standards
is their operating life. The life is limited by depletion of the rubidium
in the discharge lamp. Because studies by manufacturers of the performance
of the standards they make, they can provide estimated lifetimes based on
rubidium depletion. Because of the reliability requirements of frequency
and time standards (for example in cell phone tower electronics) they are
often swapped out for new oscillators as they get within the range of the
expected end-of-life. The large number of rubidium standards that turn up
on eBay is at least partly a result of this preventive maintenance program.
Most of the used standards likely will have limited life. However, their
low cost means you might be able to afford to buy more than one so you can
swap in one that works for one that has failed.

The standard I know that was designed with longer life in mind is the
Stanford Research Systems (SRS) line, Their PRS-10 model, for example, has
a design life of 20 years. Just look up the model for a description of the
long-term stability and low phase noise. The standard can monitor the lamp
start voltage as it rises as the rubidium depletes. These standards sell
for more on eBay because of the longer life and likelihood that they will
work for you even as used units. Some honest and knowledgable sellers can
tell you the lamp voltage. Disclosure: no financial connection with either
Ball-Efratom or PRS. I do own standards from both and I bought used ones on
eBay and they work (and are working after a couple of years) despite being
used units. On the other hand, I have some HP and Tracor/Sulzer quartz
frequency standards that are more than 20 (the HP) and 50 years old,
respectively. I’ve had to repair a couple of the Tracor units, but the
problem was almost always a transistor in the divider/amplifier stage that
failed. I also have a couple of Frequency Electronics quartz standards -
these are mil-spec units (URQ-10 and URQ-23) and work fine, but I’ve no
idea how long they were in service. They all have built-in battery packs
that are built up from “D” size nicad cells (I think - the packs are
sealed) and all have failed. They run fine without the batteries - the
power supply does not use the battery pack as a filter.

Anyone interested in time and frequency should have a look at the Time Nuts
site:

http://leapsecond.com/time-nuts.htm

SteveH




On Mon, Jul 13, 2020 at 11:36 garp66 <@green> wrote:

Does anyone know how the PTB-100 Ball Efratom Rubidium standard performs &
compares
technically (data & experience), with any of the other available
frequency standards ?

(phase noise, etc...)

-- and how it ages ?

Is the PTB-100 still a useful, viable kit ?

thank you,
rick







Re: Unknown Type 547 add-on circuit.

Chuck Harris
 

I am certain that is true, however, I have never found a connector
where it would work. It does a nice job with CRT deflection socket
pins.

I used to use an ordinary set of pointed pliers, but they only grip
the pin in two small points, which turn into pivots if you apply
any pressure. Bending the CRT pins is all but a certainty.

-Chuck Harris

william_b_noble wrote:

almost certainly either insertion or extraction tool for connector pin in a connector such as a 38999. very handy if you have to work on those connectors, lasts longer than the plastic ones




Re: Unknown Type 547 add-on circuit.

william_b_noble
 

almost certainly either insertion or extraction tool for connector pin in a connector such as a 38999. very handy if you have to work on those connectors, lasts longer than the plastic ones