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That's an old one! The newer versions have a PCB with one-shots on board. These attenuators are pulsed on/off so I'd be warry of using a bench supply to activate the solenoids; you might burn them up and then you're toast!
The better option is to plug it in to the unit and activate that way. You should be able to verify that the spring fingers are moving up and down.
With the pad assemble in place (just a few screws to hold it) you can do a few things. Place an ohmeter between the two ports and verify you have resistance (pretty low) for all combinations. Even better is to used an RF generator and a spectrum analyzer to
measure it. (a scope would also work)
You can try cleaning the springs and pads with IPA but be very careful!
Good luck.
Mark
From: [email protected] <[email protected]> on behalf of Jinxie via groups.io <paul666@...>
Sent: Saturday, September 14, 2024 9:03 AM To: [email protected] <[email protected]> Subject: [HP-Agilent-Keysight-equipment] 8566B Attenuator Service ?
Hi all,
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So I've removed the attenuator and stripped it down to a point where I can see the important bits and I cannot, from careful inspection alone, see anything amiss with it (photo attached). The pads all look nice and there are 4 of them! I'm guessing one
10dB and the rest 20dB ones. The longer ones measure about 82 ohms each across their terminals with minor variations between them and the shorter measures 52 ohms approx. The springs underneath look like brand new and the plungers do flip from on to off with
just a bit of pressure from a screwdriver but I haven't tried to actuate them under power (24V) yet. I thought I'd best pause and get some suggestions before I do something which could cause damage.
Some of you may recall from a previous thread that when the attenuator was in circuit and I attempted the calibration procedure, I saw no signal visible with the 0dB and 10dB settings. The 20, 30, 40, 50 and 60dB settings seemed okayish (some a bit noisy)
but 70dB was *very* noisy.? Any suggestions as to how to proceed?
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Thanks,
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J.
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