Re: Scan From 1404A Amplifier Manual
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Jeremy,
No problem.? I'm just glad to hear from you.? I was getting worried...?
Unfortunately, while trying to track down where the noise starts and probing around on the A9 board, I must've shorted the -12.6V rail and, apparently the safeguards didn't guard it.? I found the problems and have it running again (as you might've seen) but now I'm back to it.
Thanks for checking that.? I figured it wasn't something that would be there in a properly-functioning model and that confirms it.
Thanks again, Barry - N4BUQ
From: "Jeremy Nichols" <jn6wfo@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Monday, April 22, 2024 9:57:38 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Scan From 1404A Amplifier Manual
Barry,
Finally getting back to you on the Chop circuit. Using my 140B¡¯s internal calibrator as a source for both channels of the 1402A, I don¡¯t see any difference in beam width or intensity between Chop and Alt.?
Sorry I can¡¯t?be more helpful.? Jeremy Nichols
707-529-2639
Jeremy, The reason I'm looking into those waveforms is that when I switch the amplifier to CHOP mode, the traces become a bit "fat".? It appears there's some sort of high-frequency noise that's causing the traces to appear fatter in the negative direction - i.e. the trace is there but there's a wider "shadow" on the negative side of the trace.? I was thinking it was probably the chop multi-vibrator getting into the power rails and that still might be it; however, I'm also wondering if the blanking between the chopping action might not be working properly which could cause that ghosting effect. If I recall, the scope you obtained recently is configured just like mine with a 1421A time-base and a 1404A vertical amplifier.? If so, if you select at least two channels and select CHOP mode, do your traces change - especially do they become fatter?? I'm thinking they probably do not and there's something wrong with my scope/plugin but I'm curious to find out whether you see that same behavior and, if so, it could be an anomaly of these scopes (doubtful). Thanks, Barry - N4BUQ I have that manual. Let me check.
Would anyone have the manual for the 1404A 4-channel amplifier plugin?? I would like to see what the waveforms in Fig. 8-25 (Ring Counter Measurement Conditions and Waveforms) look like.? The online versions are pretty poor images and I can't really tell if what I'm seeing - particularly for #4 - are what they should be and a decent picture would really help.
Thanks,
Barry - N4BUQ
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