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HP8595A

Tim
 

Hello All

I'm working on my HP8595A and it has the error on the screen FREQ UNCAL. It will not go thru the frequency calibration routine. Comes up with no signal found. There is the 300mhz? -20dbm singanl coming out the test port. I have traced the signal to the A3A6 Dual mixer. Its going in but not coming out.This were am not sure how to test the dual mixer. There are two wire coming off of it. One controls the PIN diode. I believe the signal coming out switches between -10 and 10 volts. The other I believe is the mixer bias for band 1. I think it is the Dual mixer but I want to make sure before I replace.(expensive part). Any test I can preform on the mixer to see if it is good or not?

Thanks for any help.
 

Is the part number 5086-7803? If so, I have one you could try.

Cheers!

Bruce

Quoting "Tim via groups.io" <nardo53@...>:

Hello All

I'm working on my HP8595A and it has the error on the screen FREQ
UNCAL. It will not go thru the frequency calibration routine. Comes
up with no signal found. There is the 300mhz? -20dbm singanl coming
out the test port. I have traced the signal to the A3A6 Dual mixer.
Its going in but not coming out.This were am not sure how to test
the dual mixer. There are two wire coming off of it. One controls
the PIN diode. I believe the signal coming out switches between -10
and 10 volts. The other I believe is the mixer bias for band 1. I
think it is the Dual mixer but I want to make sure before I
replace.(expensive part). Any test I can preform on the mixer to see
if it is good or not?

Thanks for any help.
 

Tim,
Is there any LO signal coming out of the YIG tuned oscillator?? You may need some sort of detector or power meter to tell, since the frequency is in the 3 to 6 GHz range.
--John Gord
?

On Sun, Aug 30, 2020 at 01:23 PM, Tim wrote:
Hello All

I'm working on my HP8595A and it has the error on the screen FREQ UNCAL. It will not go thru the frequency calibration routine. Comes up with no signal found. There is the 300mhz? -20dbm singanl coming out the test port. I have traced the signal to the A3A6 Dual mixer. Its going in but not coming out.This were am not sure how to test the dual mixer. There are two wire coming off of it. One controls the PIN diode. I believe the signal coming out switches between -10 and 10 volts. The other I believe is the mixer bias for band 1. I think it is the Dual mixer but I want to make sure before I replace.(expensive part). Any test I can preform on the mixer to see if it is good or not?

Thanks for any help.
Tim
 

Thanks for the generous offer, but its a 5086-7826.?
 

¿ªÔÆÌåÓý


?Maybe YTO dead. ? the same as my 8592L




lanzhu
BG8AAK?

lanzhu@...

?
Date:?2020-08-31?05:53
Subject:?Re: [HP-Agilent-Keysight-equipment] HP8595A
Tim,
Is there any LO signal coming out of the YIG tuned oscillator?? You may need some sort of detector or power meter to tell, since the frequency is in the 3 to 6 GHz range.
--John Gord
?
On Sun, Aug 30, 2020 at 01:23 PM, Tim wrote:
Hello All

I'm working on my HP8595A and it has the error on the screen FREQ UNCAL. It will not go thru the frequency calibration routine. Comes up with no signal found. There is the 300mhz? -20dbm singanl coming out the test port. I have traced the signal to the A3A6 Dual mixer. Its going in but not coming out.This were am not sure how to test the dual mixer. There are two wire coming off of it. One controls the PIN diode. I believe the signal coming out switches between -10 and 10 volts. The other I believe is the mixer bias for band 1. I think it is the Dual mixer but I want to make sure before I replace.(expensive part). Any test I can preform on the mixer to see if it is good or not?

Thanks for any help.
 

first note that when you say the 300MHz goes into the dual mixer and does not come out, are you checking the correct output of the mixer? you must look at J2 and the frequency is 3.9214GHz.
Now assuming that you dont see that signal coming out of the dual mixer, then?the first thing to do is to make sure LO is present at the LO port of the mixer (J4) with correct amplitude (~ +14dBm). The LO frequency for 300MHz input signal is 4.2214GHz (set zero span)
if LO is present , then the mixer is probably dead and it is not super expensive but if it is not there, then you must check the output of YTO
Do you have option 009 or 010? because if you do, it can be your LODA (A3A14) is dead and also you will have an LO output on the front panel
that you can easily check. if you dont have option 009/010 then you need to check the YTO directly. It seems unlikely to me that YTO is dead because you are not
getting an LO unlevel or LO unlock errors, I suppose. If you do have a LODA in your SA, that is more suspect to me.
Tim
 

I believe I checked it at the W29 cable which is connected to J2, just before it goes to the FL1 LPF. It was easier to check it there. Am not at home at the time (vacation). So I will double check it when a I get home next week. I will also check J4 next for the correct amplitude. I don't have options 009 or 010. I really appreciate all the help from everyone.
 

No problem - just thought I mignt be able to put it to good use.

Cheers!

Quoting "Tim via groups.io" <nardo53@...>:

Thanks for the generous offer, but its a 5086-7826.
Tim
 

I check the output at J4 and I'm getting the 4.2214GHZ. Looks like the mixer? is bad. Looks like I will have to find one. Thanks for all your help. Once I get one I will let you know the out come. Thanks again.

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