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 for Windows

?