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How to test a mixer on a hp 8559 plugin in a 853 main frame

 

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
 

It very well may still be present, but it would be down quite a bit from where it should be, maybe 20 db or more down. I have an 8558 that was about 10 db down and suspected the mixer. Turned out it was the isolation capacitor in the input jack. Unless you transmitted into the mixer, they're tougher than you think and can take 10 dbm or so without problem. How's the sensitivity on the higher bands? These bypass the 1st IF and 2nd mixer.

--- In hp_agilent_equipment@..., "steven" wrote:

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
 

--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:

It very well may still be present, but it would be down quite a bit from where it should be, maybe 20 db or more down. I have an 8558 that was about 10 db down and suspected the mixer. Turned out it was the isolation capacitor in the input jack. Unless you transmitted into the mixer, they're tougher than you think and can take 10 dbm or so without problem. How's the sensitivity on the higher bands? These bypass the 1st IF and 2nd mixer.

--- In hp_agilent_equipment@..., "steven" wrote:

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
Nothing is showing at all high or low bands
 

Do you still get zero MHz response? If so, the 1st IF on are working to at least some degree. Baseline noise on wide RBW means the last IF and video are working. Can you inject some signals into the IF's directly. I think they are 2050, 321.4, and 21.4 in the 8559.
Divide and conquer. If you get the above responses, try connecting the calibrator directly to the mixer module input, bypassing the input lines and attenuator. Trace the signal path on the block diagram and work stage by stage.
Most of all, look at it as a challenge rather than a chore - have some fun with it (before you toss it across the room).

--- In hp_agilent_equipment@..., "steven" wrote:



--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:

It very well may still be present, but it would be down quite a bit from where it should be, maybe 20 db or more down. I have an 8558 that was about 10 db down and suspected the mixer. Turned out it was the isolation capacitor in the input jack. Unless you transmitted into the mixer, they're tougher than you think and can take 10 dbm or so without problem. How's the sensitivity on the higher bands? These bypass the 1st IF and 2nd mixer.

--- In hp_agilent_equipment@..., "steven" wrote:

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
Nothing is showing at all high or low bands
 

When its tuned to freq 000 there's no response

--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:


Do you still get zero MHz response? If so, the 1st IF on are working to at least some degree. Baseline noise on wide RBW means the last IF and video are working. Can you inject some signals into the IF's directly. I think they are 2050, 321.4, and 21.4 in the 8559.
Divide and conquer. If you get the above responses, try connecting the calibrator directly to the mixer module input, bypassing the input lines and attenuator. Trace the signal path on the block diagram and work stage by stage.
Most of all, look at it as a challenge rather than a chore - have some fun with it (before you toss it across the room).

--- In hp_agilent_equipment@..., "steven" wrote:



--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:

It very well may still be present, but it would be down quite a bit from where it should be, maybe 20 db or more down. I have an 8558 that was about 10 db down and suspected the mixer. Turned out it was the isolation capacitor in the input jack. Unless you transmitted into the mixer, they're tougher than you think and can take 10 dbm or so without problem. How's the sensitivity on the higher bands? These bypass the 1st IF and 2nd mixer.

--- In hp_agilent_equipment@..., "steven" wrote:

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
Nothing is showing at all high or low bands
 

How about the other tests recommended? Throw some low level signals at the various IF's and see if you get a response. If the IF's work, could be a bad mixer (I doubt it with no 000 response), more likely no LO signal. That could be a bad connector, bad YTO, etc. you can check the oscillators with a diode detector if you don't have testing at those frequencies. Enjoy the art of troubleshooting.
Hey you guys, chime in here....

--- In hp_agilent_equipment@..., "steven" wrote:

When its tuned to freq 000 there's no response

--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:


Do you still get zero MHz response? If so, the 1st IF on are working to at least some degree. Baseline noise on wide RBW means the last IF and video are working. Can you inject some signals into the IF's directly. I think they are 2050, 321.4, and 21.4 in the 8559.
Divide and conquer. If you get the above responses, try connecting the calibrator directly to the mixer module input, bypassing the input lines and attenuator. Trace the signal path on the block diagram and work stage by stage.
Most of all, look at it as a challenge rather than a chore - have some fun with it (before you toss it across the room).

--- In hp_agilent_equipment@..., "steven" wrote:



--- In hp_agilent_equipment@..., "jeffwa2scl" wrote:

It very well may still be present, but it would be down quite a bit from where it should be, maybe 20 db or more down. I have an 8558 that was about 10 db down and suspected the mixer. Turned out it was the isolation capacitor in the input jack. Unless you transmitted into the mixer, they're tougher than you think and can take 10 dbm or so without problem. How's the sensitivity on the higher bands? These bypass the 1st IF and 2nd mixer.

--- In hp_agilent_equipment@..., "steven" wrote:

If the mixer is bad will there still be a 35mhz calibraed signal on the screen? please let me know asap. thank you
Nothing is showing at all high or low bands

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