Author Topic: Advantest R3131A Spectrum Analyzer 9KHz-3GHz  (Read 87393 times)

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Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #200 on: April 20, 2016, 02:49:01 pm »
If you feed a 50 Ohm RF signal source into a 50 input Spe trump Analyser and the source signal is so heavily loaded that it is taken below its calibrated output, you have a lo impedance fault on the front end of the Spectrum Analyser.

Sadly I do not recall the exact topology of the RF input and I would need to review my photographs of that section. Your fault would suggest that an overload protection device has gone low impedance and remained so. It is not unusual to have protection limiters in sensitive RF inputs in order to protect the front end amplifiers and mixers from overload.

This needs to be investigated as it is very likely the cause of your no calibration signal situation.

In the front end of a spectrum Analyser you would expect to find the following order of components......

RF input connector
Series DC blocking capacitor
Sometimes a protection limiter
RF Attenuator, either mechanical or pin diode type.
Sometimes an RF buffer amplifier
1st Mixer to down convert input signal to 1st IF frequency.
1 st IF filter to remove unwanted mixing products and 1st LO breakthrough.
RF amplifier
The signal then passes to any further filtering and the second mixer to create the 2nd IF, then filtered, then amplified and so on.

Let me take a look at the photos I have of your modules front end and I will advise further.

Fraser
 

Offline jc81382

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #201 on: April 20, 2016, 02:59:18 pm »
Fraser,

I believe I uploaded pictures of this area back when you were asking for them.

If you need something more hi-res please let me know.

 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #202 on: April 20, 2016, 03:04:52 pm »
OK,

A quick look at the block diagram I produced shows the following input configuration......

RF input connector
I assume a DC blocking capacitor follows but not on my diagram.
0 to 50dB attenuator block
Low pass RF filter
RF relay - DPDT to insert or bypass an ERA-3 MMIC RF amplifier
Low pass RF filter
1st Mixer
IF filter
82J MMIC RF Amplifier 1
82J MMIC RF Amplifier 2
IF filter

If the input to the spectrum analyser is heavily loading an RF source you could have a low impedance fault in the RF attenuator block, MMIC amplifier (if in circuit for calibration) or the 1st Mixer if MMIC is not in circuit.

I will confirm the above above by looking at the photos of the board.

Fraser
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #203 on: April 20, 2016, 03:44:40 pm »
Here are some pictures of the older module front end. I believe this is what your unit looks like ?

The later version has just a semi rigid coax between the input connector and a self contained attenuator module positioned on the other side of the chassis.

The older design is quite a muddle of components so I will need to study it some and come back to you on its configuration.

Chores to do now so it will have to be later.

please find out how the tech went about testing the attenuator block.

Fraser
 

Offline CJay

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #204 on: April 20, 2016, 03:54:45 pm »
If you feed a 50 Ohm RF signal source into a 50 input Spe trump Analyser and the source signal is so heavily loaded that it is taken below its calibrated output, you have a lo impedance fault on the front end of the Spectrum Analyser.

Fraser

Hypothesis:

We know the SA can display the signal applied but the level indicated is drastically lower than it should be (-74dBm instead of a verified -20dBm) then we can assume it's either loading the signal down or it's somehow attenuating the signal, so how about using a T piece to monitor the signal level on the power meter when it's fed into the SA input?

Even with the (extra) impedance mismatch the power meter should, if the SA front end is still a good 50 Ohm match, indicate a relatively close power level (I *think* less than 5dB different) which would indicate the ~50dB difference is caused by a gain/buffer stage not working.

Of course, if the SA front end is faulty then the cal signal power indicated on the power meter will drop drastically.


Might help isolate the problem a little further perhaps?
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #205 on: April 20, 2016, 05:04:36 pm »
Quick and dirty sketch of front end circuit in older R3132.

No overload protection present before attenuators.

Small attenuator pad and DC block capacitors just behind input socket.

What looks to be overload detector present

Fraser
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #206 on: April 20, 2016, 05:09:04 pm »
CJay,

Thanks for pointing this out. I had, possibly incorrectly, assumed that he had injected a known level of signal into the SA and the signal had been loaded down. if it is just the reading on the faulty SA that is low, that is a whole different scenario

Apologies if I misread the symptoms. Too much going on in my life today !

Fraser
 

Offline jc81382

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #207 on: April 20, 2016, 05:09:41 pm »
is that a component that can be easily purchased and possibly replaced?
 

Offline jc81382

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #208 on: April 20, 2016, 05:14:21 pm »
Just to be clear I supplied a signal from a separate, calibrated instrument. I think it is a HP Sig Gen or something (I can confirm if you want)
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #209 on: April 20, 2016, 05:24:25 pm »
You mean the overload detector ?

That is made up of R203, R202, C200, L? and D200.

Sadly this is unlikely to cause your symptoms even if faulty.

I misread your latest posts.

From what I can now gather. You feed a signal of known amplitude into the SA and the SA shows a much lower reading than expected. Your tech has tested the attenuator and it is working OK.

Sadly the causes of a low reading or poor sensitivity in an SA are many.

You could have a low LO injection level at the first mixer.
The first mixer may be damaged (quite common if the SA is overloaded)
The I.F. chain may have a failed gain stage (MMIC).

The way to find such a fault is to trace the signal level through the analysers signal path. The point at which the expected level is not present tends to indicate a problem in the preceding stage. For example, a low output from the 1st mixer could be due to a low LO injection level or a failed diode in the mixer pair. A drop in level or lack of gain after an MMIC amplifier stage would suggest failure of the MMIC or its power supply. etc etc. For speed, the half split method is often applied to multi stage superheterodyne systems like this but damage is most likely at the front end due to abuse so you can inject a signal at the input and just follow its level through the carious stages.  Sadly this is easy to say, but harder to accomplish with the module design in the R3132. Sorry this is not likely to be a simple repair task with the module mounted in the chassis.

Fraser
« Last Edit: April 20, 2016, 05:26:11 pm by Fraser »
 

Offline jc81382

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #210 on: April 20, 2016, 05:32:19 pm »
Hmmm... I wonder if i should just look for a replacement module on e-bay or something.
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #211 on: April 20, 2016, 05:37:01 pm »
Three areas of interest in the front end circuits

1. PCB interconnections - bad joints have been found in the past. These effectively become low value series capacitors !
2. Gain stage switched in and out by a relay. The gain is provided by the 4 legged MMIC
3. 1st Mixer. It looks like a tiny pill and is mounted perpendicular to the PCB. Three legs and contains two diodes. Very fragile !
The grey blocks glued around the mixer should not be removed as they are required to suppress parasitics.

Fraser
 

Offline Fraser

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #212 on: April 20, 2016, 05:41:01 pm »
Sadly the R3132 modules are not a common item to find as they are usually still in the chassis of faulty units that are sold on ebay. It is also the module that tends to give the problems !

Fraser
 

Offline CJay

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #213 on: April 22, 2016, 01:06:42 pm »
CJay,

Thanks for pointing this out. I had, possibly incorrectly, assumed that he had injected a known level of signal into the SA and the signal had been loaded down. if it is just the reading on the faulty SA that is low, that is a whole different scenario

Apologies if I misread the symptoms. Too much going on in my life today !

Fraser

Ah, and my wording is ambiguous, I meant I was offering a hypothesis, from the information available I can't work out if the signal is being loaded down, if it's being attenuated somewhere, a measurement error or even a combination of the three.

Still, as envious as I am of anyone who can lay hands on this sort of equipment for such low prices, I'm enjoying the thought exercise and learning.
 

Offline Cech

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #214 on: September 14, 2016, 10:05:31 pm »
Standard operating procedure for replacing a Lithium cell whilst maintaining power to the SRAM...

1. Buy a 2 cell AA or AAA battery holder with flying lead output for connection to a PCB.
2. Fit 2 cells in the holder  ;D
3. Solder the flying leads to the supply rails that the Lithium battery maintains (observing polarity)
4. Cut the lithium battery off of the PCB
5. Desolder the lithium battery pins
6. Insert the new Lithium battery and solder its pins.
7. Desolder the battery holder flying leads.
8. Job done  :)

Note this is all done with the power to the equipment OFF !

For the very nervous amongst you, you can usually insert a 1K resistor in series with the battery holder flying leads, though this is not normally needed in the real world.

This approach came from an OEM service manual and is not some 'hack' method  :-+

Aurora

Doesn't this require a floating soldering iron? I don't think touching an ESD-safe tip to a powered rail is a great idea...


!! I want specify better these procedure: if you change the lithium battery and you have installed the option TG (Traking Generator),
you will lost all the additional firmware for the TG and the TG will stop to work and a error message it will appear on the display.
If someone have this problem, I have all the firmware needed to re-load again with the floppy disc, and all the procedure and password needed to load the TG firmware again. !!

I hope this can solve the problems "if" the battery it's sudden dead, otherwise if you not want losing the firmware for the TG, connect the new one battery in parallel to the old one, and after you will remove the old one.
I hope this can help someone with trouble...

Ciao
 

Offline nctnico

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #215 on: September 14, 2016, 10:31:20 pm »
Can you post this somewhere?
I suggest this website: http://www.ko4bb.com/getsimple/index.php?id=manuals
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline cncjerry

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #216 on: September 17, 2016, 01:01:23 am »
Standard operating procedure for replacing a Lithium cell whilst maintaining power to the SRAM...

1. Buy a 2 cell AA or AAA battery holder with flying lead output for connection to a PCB.
2. Fit 2 cells in the holder  ;D
3. Solder the flying leads to the supply rails that the Lithium battery maintains (observing polarity)
4. Cut the lithium battery off of the PCB
5. Desolder the lithium battery pins
6. Insert the new Lithium battery and solder its pins.
7. Desolder the battery holder flying leads.
8. Job done  :)

Note this is all done with the power to the equipment OFF !

For the very nervous amongst you, you can usually insert a 1K resistor in series with the battery holder flying leads, though this is not normally needed in the real world.

This approach came from an OEM service manual and is not some 'hack' method  :-+

Aurora

Doesn't this require a floating soldering iron? I don't think touching an ESD-safe tip to a powered rail is a great idea...


!! I want specify better these procedure: if you change the lithium battery and you have installed the option TG (Traking Generator),
you will lost all the additional firmware for the TG and the TG will stop to work and a error message it will appear on the display.
If someone have this problem, I have all the firmware needed to re-load again with the floppy disc, and all the procedure and password needed to load the TG firmware again. !!

I hope this can solve the problems "if" the battery it's sudden dead, otherwise if you not want losing the firmware for the TG, connect the new one battery in parallel to the old one, and after you will remove the old one.
I hope this can help someone with trouble...

Ciao

Great news, how do I get a copy of the code to reload the TG?  I've been needing to change my battery but was afraid of screwing up and losing the TG.

Thanks!
 

Offline Cech

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #217 on: September 21, 2016, 04:37:59 pm »
Standard operating procedure for replacing a Lithium cell whilst maintaining power to the SRAM...

1. Buy a 2 cell AA or AAA battery holder with flying lead output for connection to a PCB.
2. Fit 2 cells in the holder  ;D
3. Solder the flying leads to the supply rails that the Lithium battery maintains (observing polarity)
4. Cut the lithium battery off of the PCB
5. Desolder the lithium battery pins
6. Insert the new Lithium battery and solder its pins.
7. Desolder the battery holder flying leads.
8. Job done  :)

Note this is all done with the power to the equipment OFF !

For the very nervous amongst you, you can usually insert a 1K resistor in series with the battery holder flying leads, though this is not normally needed in the real world.

This approach came from an OEM service manual and is not some 'hack' method  :-+

Aurora

Doesn't this require a floating soldering iron? I don't think touching an ESD-safe tip to a powered rail is a great idea...


!! I want specify better these procedure: if you change the lithium battery and you have installed the option TG (Traking Generator),
you will lost all the additional firmware for the TG and the TG will stop to work and a error message it will appear on the display.
If someone have this problem, I have all the firmware needed to re-load again with the floppy disc, and all the procedure and password needed to load the TG firmware again. !!

I hope this can solve the problems "if" the battery it's sudden dead, otherwise if you not want losing the firmware for the TG, connect the new one battery in parallel to the old one, and after you will remove the old one.
I hope this can help someone with trouble...

Ciao

Great news, how do I get a copy of the code to reload the TG?  I've been needing to change my battery but was afraid of screwing up and losing the TG.

Thanks!

If you change the battery with some precautions, ther are not problems (like two battery in parallell and after you will remove the old one).
In case all will it went wrong... I can email to you all the complete procedure, file to save in the floppy disc and the password.

Ciao
 
The following users thanked this post: utkuzu, SaucySoliton

Offline utkuzu

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #218 on: November 17, 2016, 01:23:33 pm »
Standard operating procedure for replacing a Lithium cell whilst maintaining power to the SRAM...

1. Buy a 2 cell AA or AAA battery holder with flying lead output for connection to a PCB.
2. Fit 2 cells in the holder  ;D
3. Solder the flying leads to the supply rails that the Lithium battery maintains (observing polarity)
4. Cut the lithium battery off of the PCB
5. Desolder the lithium battery pins
6. Insert the new Lithium battery and solder its pins.
7. Desolder the battery holder flying leads.
8. Job done  :)

Note this is all done with the power to the equipment OFF !

For the very nervous amongst you, you can usually insert a 1K resistor in series with the battery holder flying leads, though this is not normally needed in the real world.

This approach came from an OEM service manual and is not some 'hack' method  :-+

Aurora

Doesn't this require a floating soldering iron? I don't think touching an ESD-safe tip to a powered rail is a great idea...


!! I want specify better these procedure: if you change the lithium battery and you have installed the option TG (Traking Generator),
you will lost all the additional firmware for the TG and the TG will stop to work and a error message it will appear on the display.
If someone have this problem, I have all the firmware needed to re-load again with the floppy disc, and all the procedure and password needed to load the TG firmware again. !!

I hope this can solve the problems "if" the battery it's sudden dead, otherwise if you not want losing the firmware for the TG, connect the new one battery in parallel to the old one, and after you will remove the old one.
I hope this can help someone with trouble...

Ciao

Great news, how do I get a copy of the code to reload the TG?  I've been needing to change my battery but was afraid of screwing up and losing the TG.

Thanks!

If you change the battery with some precautions, ther are not problems (like two battery in parallell and after you will remove the old one).
In case all will it went wrong... I can email to you all the complete procedure, file to save in the floppy disc and the password.

Ciao
I have the same problem. But my battery was death completely so tg and other add programs was death too. Could you send me e-mail your programs and password, please?
 

Offline utkuzu

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #219 on: November 28, 2016, 07:26:00 pm »
Standard operating procedure for replacing a Lithium cell whilst maintaining power to the SRAM...

1. Buy a 2 cell AA or AAA battery holder with flying lead output for connection to a PCB.
2. Fit 2 cells in the holder  ;D
3. Solder the flying leads to the supply rails that the Lithium battery maintains (observing polarity)
4. Cut the lithium battery off of the PCB
5. Desolder the lithium battery pins
6. Insert the new Lithium battery and solder its pins.
7. Desolder the battery holder flying leads.
8. Job done  :)

Note this is all done with the power to the equipment OFF !

For the very nervous amongst you, you can usually insert a 1K resistor in series with the battery holder flying leads, though this is not normally needed in the real world.

This approach came from an OEM service manual and is not some 'hack' method  :-+

Aurora

Doesn't this require a floating soldering iron? I don't think touching an ESD-safe tip to a powered rail is a great idea...


!! I want specify better these procedure: if you change the lithium battery and you have installed the option TG (Traking Generator),
you will lost all the additional firmware for the TG and the TG will stop to work and a error message it will appear on the display.
If someone have this problem, I have all the firmware needed to re-load again with the floppy disc, and all the procedure and password needed to load the TG firmware again. !!

I hope this can solve the problems "if" the battery it's sudden dead, otherwise if you not want losing the firmware for the TG, connect the new one battery in parallel to the old one, and after you will remove the old one.
I hope this can help someone with trouble...

Ciao

Great news, how do I get a copy of the code to reload the TG?  I've been needing to change my battery but was afraid of screwing up and losing the TG.

Thanks!

If you change the battery with some precautions, ther are not problems (like two battery in parallell and after you will remove the old one).
In case all will it went wrong... I can email to you all the complete procedure, file to save in the floppy disc and the password.

Ciao
I have the same problem. But my battery was death completely so tg and other add programs was death too. Could you send me e-mail your programs and password, please?

Thanks for your helps Cech. I will share your files and your passwords and documents. Thanks a lot.

http://www.mediafire.com/file/n3uu1gaklbytkxh/Advantest+3131+Firmware+Tracking.zip
 
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Offline SaucySoliton

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #220 on: November 28, 2016, 11:37:16 pm »
If your firmware is new enough, you don't need the floppy. Just enter the password and enable the option.  My TG seems to be working fine now.

The file appears to be a general purpose firmware upgrade. I would guess rev B01 by looking at the strings.  My unit had rev B02 already so I avoided a possible downgrade.


Thank you all for your help!
 

Offline utkuzu

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #221 on: November 29, 2016, 10:27:21 am »
I lost my factory default. Could you write me some values? Shift+5 , pass: 882323 , I RF, YTO Tune, Max1stLO and Min1stLO  hexadecimal values. Thanks your helps.
 

Offline nctnico

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #222 on: November 29, 2016, 10:38:57 am »
AFAIK you should be able to do a self calibration to get all these values right.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline utkuzu

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #223 on: November 29, 2016, 03:21:18 pm »
AFAIK you should be able to do a self calibration to get all these values right.
I cannot do self calibration because factory defaults have changed. So I need these values.
« Last Edit: November 29, 2016, 03:38:18 pm by utkuzu »
 

Offline nctnico

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Re: Advantest R3131A Spectrum Analyzer 9KHz-3GHz
« Reply #224 on: November 29, 2016, 03:31:50 pm »
I no longer have my R3131 but after I changed the battery on mine all I had to do was a self calibration and everything was fine. There is also a button near the rear on the motherboard which seems to load some defaults. I needed to press that one during startup to get my R3131 running properly after the battery swap.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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