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HP 8341B Band 3 Un Levelled

 

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Afternoon HP Group
?
????????????????????? Trying to sort our HP8341B 20GHz Sweeper but Problem with Band 3 13.5 GHz ¨C 20 GHz Un-Levelled Light is ON . Setting 0.0dBm Level on Lower Bands is OK (CW Mode) but Band 3 Levels go too ¨C13dBm to ¨C19dBm? All Voltage Rails are OK and done some Board Swaps with another Unit but not cured problem yet.... any ideas ???
?

Kind regards
Marc Christian

Telford Electronics. Old Officers Mess. Hoo Farm. Humbers Lane. Horton
Telford. Shropshire. TF6 6DJ. UK
01952 605451
www.telford-electronics.co.uk
 

I didn't have this specific one but I did have a similar issue with 8340B going unleveled in Band 2 - The solution to stop the unleveling (but not to get the output back into spec) was to reload the values from the print out in the case.?

Not sure if they got corrupted, someone played with them or something else but doing that fixed the unleveled issue and allowed me to get on with tweaking the unit.

Might be worth a try.

TonyG
 


Check for AC ripple on the power supply rails.
 

Look at the YTO alignment - put a detector on it and look at slope of RG
output (unleveled). If line is relatively smooth, alignment may work, if
you see "squiggles" possible YTO problem (still try alignment)

On Mon, October 29, 2018 10:10, MARC CHRISTIAN wrote:
Afternoon HP Group


Trying to sort our HP8341B 20GHz Sweeper but Problem with Band 3 13.5 GHz
¨C 20 GHz Un-Levelled Light is ON . Setting 0.0dBm Level on Lower Bands is
OK (CW Mode) but Band 3 Levels go too ¨C13dBm to ¨C19dBm All Voltage Rails
are OK and done some Board Swaps with another Unit but not cured problem
yet.... any ideas ???


Kind regards
Marc Christian


Telford Electronics. Old Officers Mess. Hoo Farm. Humbers Lane. Horton
Telford. Shropshire. TF6 6DJ. UK
01952 605451
www.telford-electronics.co.uk
 

I've had a problem similar to yours a few years ago with a 8340B. Swapping modules didn't help. It turned out that some of the feed-through caps (from the modules through the main PCB) had become leaky! Resistances of a few kOhms! Cleaning them (just the "isolation" part, while mounted in te PCB) solved the problem.

Raymond
 

Dear Marc Christian,

i have the same problem with an old HP8341B. With slow sweep times, however, the leveling is ok
Did you solve the leveling problems? Any idea?

Thanks Hans
 

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Just scored the 3 gig test set for 8753A

Get

 

Hello Marc

In my 8341A got the same problem, but in all bands. Checked the levels in the RF path?thoroughly. In my unit were too low or inexistent once crossed the amplifiers. So I changed both amps (expensive RF modules) and then the unit works as intended. No need to align the SYTM nor YTO.?

73!
Ruben

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