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HP 8560E spectrum analyzer YIG YTO A11 question/problem

Question asked by 4thdoctorwhofan@gmail.com on Apr 8, 2016
Latest reply on May 14, 2018 by dhamilton

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I have a 8560E which does not display any signal that is applied to the main input. After initial boot there are six error messages. After some troubleshooting, I think the problem is with the YTO A11 assembly but since I'm not that familiar with repairing this type of equipment, I thought perhaps some help is in order. The assembly for the YTO in my unit is 5086-7906. I guess there are probably no schematics available for the YIG right?

Since I am not measuring any signal directly out of the YTO, I thought perhaps something is wrong with the drive to it instead of a faulty YIG. The drive comes from connector J3 on the A14 board. Below is what I am getting on the J3 connector:

Pin 1: -14.98V (-15V supply voltage)
pin 4: 4.61V (with the connector removed I get 4.96V, not sure if this is a problem;+5V supply)
pin 5: -3.3V (main coil +)
pin 6: -14.98V (main coil -)
pin 8: 14.75V (with the connector removed I get 14.88V, not sure if this is a problem;+15V supply)
pin 9: voltage fluctuates between .5V & 2V (FM- signal)(I read 15mV with the connector removed)
pin 10: voltage fluctuates between .5V & 2V (FM+ signal) (I read 13.6V with the connector removed)

Does any of this seem normal or is something way off base? I'm just not sure what "normal" readings would be on the connector. The attached file is the connector in question.

Any advice or help would really be appreciated.
Thanks!
Tony

Edited by: 4thDoctorWhoFan on Apr 8, 2016 8:01 PM

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YTO_A11.jpg131.3 KB

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PA0ALV Apr 13, 2016 2:59 AM

Hi Tony,

I have had the same faillure defective YTO.

If you have another analyser with LO out, it's possible to see the call signal in an irregular sequence.
Even a signal generator will do the job. The signal replaces the original YTO frequency.
The signal source has to be steady, so no sweep and about 3,3 GHz.

I have tried this example and surprising some spikes where seen on the CRT.
Conclusion YTO defect.
Maybe it helps you to repair the analyser.

Good luck
Ary

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PA0ALV Apr 15, 2016 5:01 AM

Hi Tony,

Searching my archive, found the following info !
It's not the same YTO but it will give you a look inside the YTO.
It do no harm to dismantle the YTO carefully !.
Look after a burnt small resistor on the pcboard.
Following the schematic measuring the Main and FM coil seldom faulty.
Mostly of the time the problem is a faulty oscillation transistor.

I hope this will give you a step forward .

Greetz
Ary

Attachments

print YIG.pdf140.7 KB
print YIG.pdf140.7 KB
099.jpg223.5 KB
038.jpg240.5 KB

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bysteve May 14, 2016 4:39 AM

Hi, I worked on these units for a lot of years at HP/Agilent/UK service centre and elsewhere.

If one of your error messages is "334 LO AMPL" Then is almost certain that the YIG Oscillator is U/S.

If you have another Spectrum Analyser which can cover the frequency range 3 - 8 GHz, connect the front panel LO output from your suspect unit to the other analyser's RF input, put your faulty unit in a slow sweep rate (5 or 10 seconds) and you should see the LO from your Faulty unit sweep across the screen from about 3 - 6.8 GHz. The amplitude should be about +15dBm. If it is missing, has holes in it's coverage, or the power is low then almost certainly the YIG (5086-7906) is defective. If you don't have another Analyser, you can put your faulty unit in Zero Span mode and use an RF Power Meter. These YIGS cannot be repaired without highly specialised knowledge and equipment. A replacement from Keysight is £2802 and may not be available. A better option may be Vida Products in Santa Rosa who offer a repair service for YIGS and similar assemblies. The Service Manual (08560-90157) can be downloaded from Keysight and may help you.

Good Luck

Steve B

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hardyhansen Jun 3, 2016 5:49 PM

Yahoo! Groups

Ask at this group-someone might help you

Hardy

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dhamilton Jun 8, 2016 7:54 AM

I have rebuilt Yigs in stock for most of the legacy keysight products.

PM me and I can help.

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ramesh May 11, 2018 2:15 AM

hello all,

i have a spectrum alnalyser HP8594A which is faulty.

Problem is (1)FREQ UNCAL (2) calibration fails stating CAL:SIGNAL NOT FOUND

I measured 10 pin connector on YTO (5086-7833) oscillator with digitalmultimeter after the analyser was switched -on.

pin nos. standardsignal obtained

Pin1 = minus 15v = minus 15.02v

pin2 = a gnd = -

pin3 = a gnd = -

pin4 = +5v = +5v

pin5 = maincoil+ = +14.81v

pin6 = maincoil- = +9.63v

pin7 = a gnd = -

pin8 = +15v = +14.83v

pin9 = FM-signal = 0.041v

pin10 = FM+signal = 0.041v

Are these obtained values at pin 5,6, 9, 10 right or wrong.

please ur suugestion or views are appreciated.

ramesh

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dhamilton @ ramesh on May 11, 2018 8:35 AM

Hello Ramesh,

If you have your YIG oscillator out of the RF deck, reconnected to the power cable and turned on. Set the analyzer to 1 GHz Center Frequency and Zero Span. Measure the signal coming out of the YIG. It should be 4921.4 MHz ± 10 MHz @ approximately 10 dBm.

That will test to see if the YIG is working. If the YIG is good, check to see if the 300 MHz calibrator signal is present. If you still don’t have a calibration signal your input RF attenuator or 1st converter may be blown.

Regards,

Dave Hamilton

1 person found this helpful

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ramesh @ dhamilton on May 12, 2018 12:53 AM

Hi Dave Hamilton,

CAL OUT is present, 300MHz @approx.-20dBm.

Using power meter HP 436A i will try to measure oscillator output 4921.4 MHz @10dBm.

THANK YOU DAVE

Ramesh

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ramesh @ ramesh on May 12, 2018 1:43 AM

Hi Dave Hamilton,

I connected output of oscillator to power meter with CF @1 GHz, zero span, no response found. So the problem might be with YTO .

Actually the problem with the spectrum analyser is

1.When the unit is switched-on FREQ UNCAL is displayed

2.Tried calibrating by connecting CAL OUT to RF IN, result SIGNAL NOT FOUND

3.The trace line (sweep movement) is slow in movement when span >10 MHz, slower <10MHz

But if the Counter-lock flat cable is disconnected FREQ UNCAL disappears & trace (sweep movement) is normal.

That's the reason why Iam not able to find the exact faulty part.

regards

RAMESH

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dhamilton @ ramesh on May 14, 2018 10:26 AM

Hello Ramesh,

If you tested the YIG as stated earlier, then the YIG is dead.

On the Freq Cal issue, with the counter board removed, the sampler circuitry is removed which checks for a signal before a sweep is started. When removing the board, the sweep inhibit line is not activated.

PM me and I can provide a quote for a rebuilt YTO.

Regards,

Dave Hamilton

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10 Replies

PA0ALV Apr 13, 2016 2:59 AM
Mark Correct
Correct Answer
Hi Tony,

I have had the same faillure defective YTO.

If you have another analyser with LO out, it's possible to see the call signal in an irregular sequence.
Even a signal generator will do the job. The signal replaces the original YTO frequency.
The signal source has to be steady, so no sweep and about 3,3 GHz.

I have tried this example and surprising some spikes where seen on the CRT.
Conclusion YTO defect.
Maybe it helps you to repair the analyser.

Good luck
Ary
Like • Show 0 Likes0
Actions
PA0ALV Apr 15, 2016 5:01 AM
Mark Correct
Correct Answer
Hi Tony,

Searching my archive, found the following info !
It's not the same YTO but it will give you a look inside the YTO.
It do no harm to dismantle the YTO carefully !.
Look after a burnt small resistor on the pcboard.
Following the schematic measuring the Main and FM coil seldom faulty.
Mostly of the time the problem is a faulty oscillation transistor.

I hope this will give you a step forward .

Greetz
Ary
Attachments
- print YIG.pdf140.7 KB
- print YIG.pdf140.7 KB
- 099.jpg223.5 KB
- 038.jpg240.5 KB
Like • Show 1 Like1
Actions
bysteve May 14, 2016 4:39 AM
Mark Correct
Correct Answer
Hi, I worked on these units for a lot of years at HP/Agilent/UK service centre and elsewhere.
If one of your error messages is "334 LO AMPL" Then is almost certain that the YIG Oscillator is U/S.
If you have another Spectrum Analyser which can cover the frequency range 3 - 8 GHz, connect the front panel LO output from your suspect unit to the other analyser's RF input, put your faulty unit in a slow sweep rate (5 or 10 seconds) and you should see the LO from your Faulty unit sweep across the screen from about 3 - 6.8 GHz. The amplitude should be about +15dBm. If it is missing, has holes in it's coverage, or the power is low then almost certainly the YIG (5086-7906) is defective. If you don't have another Analyser, you can put your faulty unit in Zero Span mode and use an RF Power Meter. These YIGS cannot be repaired without highly specialised knowledge and equipment. A replacement from Keysight is £2802 and may not be available. A better option may be Vida Products in Santa Rosa who offer a repair service for YIGS and similar assemblies. The Service Manual (08560-90157) can be downloaded from Keysight and may help you.
Good Luck
Steve B
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Actions
hardyhansen Jun 3, 2016 5:49 PM
Mark Correct
Correct Answer
Yahoo! Groups
Ask at this group-someone might help you
Hardy
Like • Show 0 Likes0
Actions
dhamilton Jun 8, 2016 7:54 AM
Mark Correct
Correct Answer
I have rebuilt Yigs in stock for most of the legacy keysight products.
PM me and I can help.
Like • Show 0 Likes0
Actions
ramesh May 11, 2018 2:15 AM
Mark Correct
Correct Answer
hello all,

i have a spectrum alnalyser HP8594A which is faulty.
Problem is (1)FREQ UNCAL (2) calibration fails stating CAL:SIGNAL NOT FOUND

I measured 10 pin connector on YTO (5086-7833) oscillator with digitalmultimeter after the analyser was switched -on.

pin nos. standardsignal obtained

Pin1 = minus 15v = minus 15.02v

pin2 = a gnd = -

pin3 = a gnd = -

pin4 = +5v = +5v

pin5 = maincoil+ = +14.81v

pin6 = maincoil- = +9.63v

pin7 = a gnd = -

pin8 = +15v = +14.83v

pin9 = FM-signal = 0.041v

pin10 = FM+signal = 0.041v

Are these obtained values at pin 5,6, 9, 10 right or wrong.

please ur suugestion or views are appreciated.

ramesh
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- dhamilton @ ramesh on May 11, 2018 8:35 AM
  Mark Correct
  Correct Answer
  Hello Ramesh,
  
  If you have your YIG oscillator out of the RF deck, reconnected to the power cable and turned on. Set the analyzer to 1 GHz Center Frequency and Zero Span. Measure the signal coming out of the YIG. It should be 4921.4 MHz ± 10 MHz @ approximately 10 dBm.
  
  That will test to see if the YIG is working. If the YIG is good, check to see if the 300 MHz calibrator signal is present. If you still don’t have a calibration signal your input RF attenuator or 1st converter may be blown.
  
  Regards,
  
  Dave Hamilton
  1 person found this helpful
  Like • Show 1 Like1
  Actions
  - ramesh @ dhamilton on May 12, 2018 12:53 AM
    Mark Correct
    Correct Answer
    Hi Dave Hamilton,
    
    CAL OUT is present, 300MHz @approx.-20dBm.
    
    Using power meter HP 436A i will try to measure oscillator output 4921.4 MHz @10dBm.
    
    THANK YOU DAVE
    
    Ramesh
    Like • Show 0 Likes0
    Actions
    - ramesh @ ramesh on May 12, 2018 1:43 AM
      Mark Correct
      Correct Answer
      Hi Dave Hamilton,
      
      I connected output of oscillator to power meter with CF @1 GHz, zero span, no response found. So the problem might be with YTO .
      
      Actually the problem with the spectrum analyser is
      
      1.When the unit is switched-on FREQ UNCAL is displayed
      2.Tried calibrating by connecting CAL OUT to RF IN, result SIGNAL NOT FOUND
      3.The trace line (sweep movement) is slow in movement when span >10 MHz, slower <10MHz
      
      But if the Counter-lock flat cable is disconnected FREQ UNCAL disappears & trace (sweep movement) is normal.
      
      That's the reason why Iam not able to find the exact faulty part.
      
      regards
      RAMESH
      Like • Show 0 Likes0
      Actions
      - dhamilton @ ramesh on May 14, 2018 10:26 AM
        Mark Correct
        Correct Answer
        Hello Ramesh,
        
        If you tested the YIG as stated earlier, then the YIG is dead.
        
        On the Freq Cal issue, with the counter board removed, the sampler circuitry is removed which checks for a signal before a sweep is started. When removing the board, the sweep inhibit line is not activated.
        
        PM me and I can provide a quote for a rebuilt YTO.
        
        Regards,
        
        Dave Hamilton
        Like • Show 0 Likes0
        Actions

HP 8560E spectrum analyzer YIG YTO A11 question/problem

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