Here's how to turn it on from the menu

Enable the internal 50 MHz amplitude reference signal as follows: (ESA E4401B and E4411B)Press Input/Output, Amptd Ref (On).

Yeah,?

This has me scratching my head. ?Power supplies on a8 look good.

Get

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From: [email protected] <[email protected]> on behalf of rpoz28cam via Groups.Io <rpoz28cam@...>
Sent: Saturday, March 30, 2019 1:22:52 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] E4401B No 50MHZ Cal signal

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Hmmm.. Ok.? -20dbm and 21.7Mhz.? Interesting case of trouble.? Controller / PLL power supplies in check?? Loops locked I guess, thinking what else to check.??

On Saturday, March 30, 2019, 1:13:21 PM CDT, Michael Williams <mike@...> wrote:

Hi Jon,

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Yes, I see an IF signal coming out of A8J3 when I follow the RF verification procedure when using an *external* 50 MHZ source.? The signal does very with attenuation, as describe in the service guide.?

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-- Mike

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From: <[email protected]> on behalf of "rpoz28cam via Groups.Io" <rpoz28cam@...>
Reply-To: "[email protected]" <[email protected]>
Date: Saturday, March 30, 2019 at 1:07 PM
To: "[email protected]" <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] E4401B No 50MHZ Cal signal

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Mike,

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Can you see a 21.7Mhz IF signal on the cable plugged into A3J2?? I was looking over pages 55 - 75 of the ESA Service guide for a E4401B and there is a verification process to check on RF deck function.? I only suggest this because your original message stated your seeing signals but wasn't sure if they were as expected in Amplitude and correct frequency.??

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Jon

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On Saturday, March 30, 2019, 12:58:42 PM CDT, Tom B <tbryan@...> wrote:

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Did you make sure the cal signal was turned on?? You can turn it off on the E4401B.

On 3/30/2019 1:39 PM, Michael Williams wrote:

Hi Mark,

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Thanks for the reply and the thoughts.

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From the info in my CLIP, the 50 MHZ CAL signal is generated by dividing the 800 MHZ 2^nd LO by 16.? The 2^nd LO gets its power from the TEST MUX (U56).? This mux is dead – no enable signal, no activity on any of the control lines.? That’s where I’m stuck, I can’t figure out if it’s a hardware or software issue that is causing the 2^nd LO to not get turned on.? The CLIP is not very clear on what tells the fractional divider (U55) to enable it.

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The 10MHz reference clock is the timing source for the 800 MHZ 2^nd LO, and is present, both internally and at the 10MHZ output connector in the back.

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Thanks again,

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Mike

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