?

Absolutely agree, but it can be problematic to dig into the test set?
if the problem is in the 85202.? The test set is more easilly damaged,?
particularly if you are unfamiliar with its innards.

The other thing he should confirm is the 834X OUTPUT at the test set input.

Cheers!

Bruce

Quoting Lothar baier <Lothar@...>:

> True but in all the years I been fixing those units back at tucker?
> about 85% of all failures were testset related
>
> Sent from Mail<> for Windows
>
> From: Bruce via groups.io<mailto:bruce@...>
> Sent: Wednesday, March 2, 2022 4:24 PM
> To:?
> [email protected]<mailto:[email protected]>
> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>
> Note that the problem could also be in the 85102 IF unit.? Do you have
> either the test set simulator or a second test set of some kind?
>
> The test set simulator is a plug that fits the IF RF outputs and has a
> connector for the 20.4MHz signal from the IF to provide a signal
> approximating the outputs from the test set.
>
> It would be bet to confirm the 85102 before digging nto the 8516.
>
> Cheers!
>
> Bruce
>
> Quoting Lothar baier <Lothar@...>:
>
>> Ok so the 8510 test-sets have 4 samplers , 2 of them are connected
>> to the couplers , the other 2 are reference samplers , those are
>> connected to the switch/splitter , the RF coming in from the source
>> is split inside of this assembly in 3 paths , 2 reference paths that
>> are connected to the reference samplers the third one is routed to a
>> switch which switches the RF either to coupler 1 or 2 while
>> terminating the unused coupler in 50ohm !
>> NO IF FOUND usually indicates that either one or both reference
>> samplers does not receive a signal or that the signal level is to
>> low .
>> This can have multiple reasons :
>>
>>?? 1.? The Source output level is to low , cable from source to the
>> testset might be broke
>>?? 2.? Doubler amplifier assembly is bad
>>?? 3.? Switch /Splitter bad
>>?? 4.? Bad sampler or sampler driver
>> Note that for 2 or 3 defective can also mean issues with the control
>> circuits !
>> You can also get this error if you have power holes in the source
>>
>> First thing to do is to set the start and stop frequency to a small
>> range like 2-4GHz or 1-2GHz and see if the error goes away, if it
>> does then increase the sweep range to see where the error starts to
>> appear !
>> Next check the source level at the end of the cable you use to
>> connect the source to the test-set , make sure the level is within
>> the range the test-set can process
>> If this doesn’t resolve things take the lid of the test-set and
>> check your DC Voltages to ensure they are all correct , next
>> disconnect the output of the doubler amplifier block and check if
>> you have RF coming out ,? you can also connect the source directly
>> to the cable that connects the doubler to the switch splitter set
>> your sweep from 2-10GHz if the error goes away you have a problem
>> with the doubler or doubler control if its still present you have to
>> check the signal at your samplers if the signal is there your
>> sampler is bad or the sampler driver
>>
>> Sent from Mail<> for Windows
>>
>> From: ratn9ne via groups.io<mailto:ratn9ne@...>
>> Sent: Wednesday, March 2, 2022 2:37 PM
>> To:
>> [email protected]<mailto:[email protected]>
>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>
>> I have a complete 8516 VNA setup and it was intermittently working
>> with a standard DB25 Thru cable. Right now I am stuck on "NO IF
>> FOUND" error and out of ideas.
>>
>>
>>
>>
>>
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