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Re: 8341A *restoration adventure*

 

Hi Bruce!

I checked the ripple of the eight regulated rails and everyone stays between 10 to 15 mV, I think that is ok.

- On the scope-crystal setup:
My scope is digital and x-y mode is crap. So I set two multimeters and the scope in normal mode. The first test you mentioned I think is failed and the ALC I think is ok. You can judge by yourself seeing a couple of videos I recorded, one of a single 60 second sweep from 2 to 20 gig with lvl pre-METER mode set to 2 dBm (note crystal measurement doing crazy jumps from 1.x volts to almost zero), and the other video I have to turn several times the knob and then it has a smooth ride from zero to arround minus seventy milivolt.


I am a bit confused after that...?

Kind regards,
R.
Re: HP 5245L Electronic Counter Prefix 724-

 

Yes indeed thats the M model oven and they are very good. Its the same oven used in the Cesium 5061a/b. Though the internal EFC is a bit different.
I have one in a 5248M. Better frontend from what I see. Maybe a drop newer design. But still works.
Regards
Paul
WB8TSL
Re: HP 5245L Electronic Counter Prefix 724-

 

On Fri, Nov 12, 2021 at 01:37 PM, Marco Marchesi wrote:
No schematics available on the web
Not free, that is.
Artek Manuals sells good scans for just over USD 10,-.

Raymond
Re: HP 5245L Electronic Counter Prefix 724-

 

Your insight was spot on!
I wonder how can I have been so absent-minded!
It is exactly HP 5245M!

No schematics available on the web
Re: Keysight DVM 34465A Temperature/TC?

 

Bonjour seul,
yes the 34465A has a built in Thermo Couple function for J, K, E, T, N, R types.
It also got an internal reference junction, afaik.
Please read the manual for details.
Frank
Re: Buying a used VNA

 

Here both the vintage PNA and the low cost VNA are used to look at the same home made Beatty standard.?

70mm_50k_4p4G_V2P4_2p08_101pts_A_cal.PNG
70mm_PNA_401pts.PNG

Re: Buying a used VNA

 

On Fri, Nov 12, 2021 at 05:16 PM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
There is a circuit, which I think was published in QEX, that drops the frequency of a VNA by mixing the input with the 10 MHz reference output. So 0-300 kHz would be seen at 10 to 10.3 MHz.
?
The software supports using external mixers for both up and down conversion.? There no free ride of course.?? My interest in the lower frequency (20kHz and up) is for PDN measurements.? I would like to have a continuous sweep with a fairly wide dynamic range (PDNs can have a fairly low impedance).?? What I have been doing to get around it is using a second vintage analyzer and stitching the Touchstone files together.?? For example:

"Some time ago I had come across an paper written by Jeroen Belleman where he was studying the parasitic shunt capacitance of some 1206 resistors. "
https://www.eevblog.com/forum/rf-microwave/shunt-capacitance-of-1206-smd-resistors-jeroen-belleman-december-2010/msg3606722/#msg3606722

It's not ideal but I knew that before I bought the PNA.? Copper Mountain Tech offers a product that would have been perfect for my hobby use, except for the price tag. ?

I made a video where I attempt to demonstrate making a few PDN measurements with a $50 VNA.? The software is is very similar to what I use with the PNA (basically running it headless).
Re: HP 5245L Electronic Counter Prefix 724-

 

On Fri, Nov 12, 2021 at 12:06 PM, Raymond Domp Frank wrote:
Maybe irrelevant - but wouldn't that OCXO belong in a 5245M, not a 5245L?
My 5245M manual applies to 716- and up...

Raymond
Re: HP 5245L Electronic Counter Prefix 724-

 

Maybe irrelevant - but wouldn't that OCXO belong in a 5245M, not a 5245L?

Raymond
OT: Extender for flat (flex PCB) 4 wire ribbon cable

 

I've got a replacement touch screen that has a four wire (1mm pitch) flat
flex PCB ribbon cable that is too short (3" or 70cm long) that I need to
extend to about 10" (say 25cm).

I think what I need is a four wire version of this:
<> in 1mm pitch ...

But so far I've not found one

D.
Keysight DVM 34465A Temperature/TC?

 

Bonjour a tous: We use thermocouples to check power dissipation in SMPS, and to calibrate SMD solder pots with RoHS solder like SAC100.
We have many type K TC from Fluke, Kiethley and hommade spot weleded.

For my Keysight 34465A DVM, I wonder about a TC function?

I also have an ancient Yokogawa DCV/DCI calibrator (2601?) with the cold junct type K TC adapter.
But no idea the procedure to use it!

Many thanks again

Jon
Re: Buying a used VNA

 

On Wed, 5 May 2021 at 16:57, Joe Smith via <joeqsmith49=[email protected]> wrote:
The only real downside to the instrument has been the 300KHz lower limit. 10KHz would have been far more useful for me but I knew that going into it.??
There is a circuit, which I think was published in QEX, that drops the frequency of a VNA by mixing the input with the 10 MHz reference output. So 0-300 kHz would be seen at 10 to 10.3 MHz.

Dave

HP 5245L Electronic Counter Prefix 724-

 

Hi All,?
I`m restoring this unit.
At the moment I`m troubleshooting the A24-A25-A26 Oscillator ensemble where no signal is coming out.
But there is a catch.
I can`t find any documentation about this prefix!
And the oscillators boards look quite different from the ones in the most common series (e.g. 648-).

A snapshot is attached above.
Does someone have some documentation?
Many thanks in advance.

Marco
Re: 8341A *restoration adventure*

 

OK soyou can do the tests with the detector and a scope.

Drive the scope X with the SWEEP OUT from front panel and the Y from the detector.
PRESET,START=2G, STOP=20G, METER - sweep should be continuous with lots of "wiggles"
Note the lowest point on the sweep, and set the leveled output for 2 dB (or so) less than that and run the 2-20Gig sweep - should be a relatively straight line with some slope (due to cable) at the 20G end

You can also run the ALC test - PRSET,CW,SHIFT METER - use RPG to vary output which should vary smoothly from max to min (maybe -10 dBm). I'm going to guess that this test fails - remember that you need to turn RPG CCW several turns B4 it has any effect. Once it starts to have an effect, output should vary smoothly. If not, there is an ALC problem

Cheers!

Bruce


Quoting RubenRubio <rubenrb2019@...>:

Hi again

Thanks for those steps Bruce, but currently I don't have an SA, I sold my 1.8 gig last month and planned to buy an 8566B asap. For now I only have a 5342A microwave counter, power sensor 8481A along with 436A meter and 8472B crystal detector.

The cal data paper matches series number of the machine and model too. But I think is weird because the high band detector, the coupler and the step attenuator has APC 3.5 connectors and 26.5 gig stickers :S

I want to measure the power supply ripple in all rails... I saw a table with max current for each rail, but not the maximum allowed ripple. Anyway I want to check that before do more things. This evening?I've been taking down the front panel to check the smashed area for damage and it seems, except for the output connector and frontal frame,? ok.

Tomorrow I'll check the CW behavior with METER or CRYSTAL modes, because I have a 2 gig power splitter, maybe it helps for troubleshooting. Also, I have to study block diagrams of the RF section, but for now I think that the ALC is the culprit... the two detectors are fine, because the fail happens in band 0 and the other bands too.

I'll keep you in touch, thanks for all :)

Regards,
R.
Re: Buying a used VNA

 

I know Keysight is pretty proud of their TDR option for the PNA.? Shown below you can see how this vintage tech compares with a low cost $200 VNA out of China measuring a home made 70mm Beatty standard.??

/g/NanoVNAV2/topic/tdr_range_and_resolution/85253511?p=,,,20,0,0,0::recentpostdate/sticky,,,20,2,0,85253511,previd=9223372036854775807,nextid=1634756003901192623&previd=9223372036854775807&nextid=1634756003901192623
Re: 8341A *restoration adventure*

 

Hi again

Thanks for those steps Bruce, but currently I don't have an SA, I sold my 1.8 gig last month and planned to buy an 8566B asap. For now I only have a 5342A microwave counter, power sensor 8481A along with 436A meter and 8472B crystal detector.?

The cal data paper matches series number of the machine and model too. But I think is weird because the high band detector, the coupler and the step attenuator has APC 3.5 connectors and 26.5 gig stickers :S

I want to measure the power supply ripple in all rails... I saw a table with max current for each rail, but not the maximum allowed ripple. Anyway I want to check that before do more things. This evening?I've been taking down the front panel to check the smashed area for damage and it seems, except for the output connector and frontal frame,? ok.

Tomorrow I'll check the CW behavior with METER or CRYSTAL modes, because I have a 2 gig power splitter, maybe it helps for troubleshooting. Also, I have to study block diagrams of the RF section, but for now I think that the ALC is the culprit... the two detectors are fine, because the fail happens in band 0 and the other bands too.

I'll keep you in touch, thanks for all :)

Regards,
R.

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Re: HP 3582A processor board 03582-66507 processor board wanted

 

Maybe we can help you fix yours. Can you enlighten us as to what you've learned so far about the issue?

Dave Casey


On Thu, Nov 11, 2021 at 10:48 AM mill_glen_chevy via <brstpr=[email protected]> wrote:
Good day folks,

I'm looking for a good processor board for my 3582A.? I've narrowed down the issue to the processor board and would like to get one so I can release this one into the wild.? I'd hate to part it out since its so close to getting back to work.? Unfortunately, I don't really have the skill set necessary to repair the one I have.? Any help is appreciated.

Thanks

Re: 8341A *restoration adventure*

 

Questions:
1) Do you have a spectrum analyzer that can STORE (MAX HOLD on an 8566) 2G - 20G sweep?
2) Do you have a detector that can measure power from about 25dBm to -10 dBm (power meter or xtal detector)?

I am sorry, I forgot to tell you to use CW mode when doing the PRESET,SHIFT,METER test - my fault.

Here is a test that will try to isolate the problem to either unleveled RF output or the ALC system - it assumes you have a spectrum analyzer that can store a full band sweep.

If so, do the following:

1) Set the Spectrum Analyzer (SA) for reference level 30 dB with an attenuation of 40 dB
2) Set the 8341 for 13 GHz (or so) CW mode and press METER - This will essentially disable the ALC system
3) Confirm that the power is within the range of the SA settings (Trace is on scale)
4) Record a sweep from 2G to 20G and note the max and min power levels (Picture would be good)
Note: the best way to record this trace is to set the 8340 sweep rate to approximately 30ms and the SA sweep time to about 200 SEC - put the SA od MAX hold if your SA has that feature. Take a picture of the result.
5) Now on the 8341 do: PRESET,START=2G,STOP=20G,POWER = 5db LOWER than the lowest power recorded in step 4. Leave the SA settings as before and do a sweep from 2-20G (picture of the result would be good)
Next repeat the ALC test I described before:
1) set 8341 PRESET, CW,SHIFT,METER - Rotate the RPG CCW and watch the power output on a spectrum analyzer and watch the 8341 power meter. On the SA, the power should go smoothly from high power (about 20dBm) to low power (-10 to -15dBm), The 8341 power meter should should follow the SA once the power out gets to 5dBm (or so). Note that you will have to turn the RPG CCW and it will take several turns before it starts to take effect.

Based on what you have said so far, I suspect the ALC, but lets do these tests before trying anything else.

Cheers!

Bruce



Quoting RubenRubio <rubenrb2019@...>:

Sorry for machine gun posts...

Updating:
The step attenuator is working, ten by ten dB, it downs the power quite exactly. Is the fine attenuation that fails, loosing relation with the actual power at output.

Best regards,
R.
Re: 8341A *restoration adventure*

 

I would consider recovering the cal constants from EEROM - there are directions in the manual.

BEFORE doing this I would write down both the current (Working constants), the constants in the battery backed up memory,and the original constants. I would then relod the original factory constants.

Question - does the list of constants supplied with the machine match the serial number? And is the model specified as 8341 or 8340 on the constants list.

Cheers!

Bruce

Quoting RubenRubio <rubenrb2019@...>:

Updating: Today, at the first start, the light FAULT in red is now on ?? the entry display shows 'cal defaulted' and the max freq now showed 26.5 GHz, so my 8341A becomes a 8340A this night :D (one interesting point: during visual inspection I saw that the high band detector mounted on the output coupler, covers 2 to 26.5 gig) I think I mess up something with the cal constants yesterday ??

Preset + Shift + M4 = full diagnostic pass

Preset + Shift + Meter = power dBm display continues showing random numbers constantly changing and actual output follows that random numbers.

Because the sweeping causes my meter to show crap, I tried in CW mode (now I can reach 26.5 gig, this is amazing, but I haven't 26.5 counter or SA to check that) but the behavior is worse than yesterday.

This is getting worse and worse xD

Regards,
R.
Re: HP 3562A data and plot file formats?

 

Yes. HPGL files are no problem, the binary files are. But I have at least located the Keysight utilities:?https://www.keysight.com/fi/en/lib/software-detail/instrument-firmware-software/keysight-model-35670a-sdf-utilities-sw443.html
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