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Replies:
3
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1
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Last Post:
Aug 10, 2012 7:40 AM
Last Post By: DominiqueB
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Posts:
10
Registered:
07/26/12
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HP 83640A - Frequency error on Low Band (10MHz to 2.4GHz)
Posted:
Jul 26, 2012 1:48 PM
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Dear all,
My HP 83640A is working fine (frequency, level, sweep) from 2.4GHz up to 40 GHz, but the Low Band from 10MHz up to 2.4GHz has an issue on the frequency. On this band, the frequency is exactly 100 MHz below the frequency displayed.
For example, with a CW displayed of 1GHz, the actual frequency produced is 900MHz. This 100 MHz negative shift is exactly respected on the Low Band. The level is fine.
Not found any relevant information on the Service Manual nor in the Troubleshooting Manual.
And impossible to locate the CLIPs for this generator.
I would be very interested is somebody could give me some help.
Thanks in advance.
Greetings,
DominiqueB
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Posts:
1,110
Registered:
07/24/09
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Re: HP 83640A - Frequency error on Low Band (10MHz to 2.4GHz)
Posted:
Jul 26, 2012 3:08 PM
in response to: DominiqueB
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Hi DominiqueB -
When the 83640A is switched to low band, 10 MHz to 2.4 GHz, the frequency is derived by heterodyning the YO with the 100 MHz reference signal.
Your unit has probably lost the 100 MHz reference signal to the low band assembly, or the low band assembly itself has a problem where the YP is mixed with the 100 MHz reference signal.
I hope this helped -
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Posts:
10
Registered:
07/26/12
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Re: HP 83640A - Frequency error on Low Band (10MHz to 2.4GHz)
Posted:
Jul 27, 2012 10:38 AM
in response to: tabbott
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Hi Tabbott,
Thanks for your answer.
The 100MHz 0dBm coming from A7 reference is good and arrives well at the input of the bloc A24 Low Band. So the frequency synthesis is fine ... but the Low Band A24 seems to have problem.
Is it possible to open this block and check the elements inside ?
Is there somewhere any documents related to this Low Band element ?
Thanks for your help.
Cheers,
DominiqueB.
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Posts:
10
Registered:
07/26/12
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Re: HP 83640A - Frequency error on Low Band (10MHz to 2.4GHz)
Posted:
Aug 10, 2012 2:11 AM
in response to: DominiqueB
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Dear all,
Having got the Troubleshooting Guide, I went ahead on the research.
Strangely, without any hardware modification, I get now an error message when running the Selftest Full :
" Failed : RF Lowband Tuning Voltage - Refer Repair manual Paragraph RF.000"
" V - Tune mV : Meas : - 201mV Min : - 11000mV Max : - 400 mV"
And :
" Failed 269.000 RF : Lowband Locked Check"
" HTE Unlocked"
And, when the generator is working, if I program a CW between 10MHz and 2.3 GHz, I get the message "Unlock (HET Unlock)".
Here I am today, I will continue exploring the manuals, but it's not easy without the schematics. I would be very interested to have information on what is there inside the A24 Low Band module (5086-7463), and as well to get the schematic of the A20 Interface board. Actually, the Troubleshooting Manual focus onto these two elements as a possible faulty elements.
I would be interested to know what means "HTE", and in which board (or module) is located the faulty PLL. I didn't found this in the manuals.
Any information will be really welcome. Thanks a lot for your help.
DominiqueB.
Edited by: DominiqueB on Aug 10, 2012 7:33 AM
Edited by: DominiqueB on Aug 10, 2012 7:39 AM
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