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Re: 8557A/8558A Switch Board Assembly - Contact Fingers


 

Just don't grind those fingers and inhale or eat the BeCu dust.

Barry - N4BUQ


From: "Frank Mashockie" <fmashockie@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Tuesday, March 19, 2024 9:09:22 PM
Subject: Re: [HP-Agilent-Keysight-equipment] 8557A/8558A Switch Board Assembly - Contact Fingers
Thanks Martin!

Yea I just got done taking the switch assembly apart.? So it looks like I have two missing contact fingers.? One on the time base switch and one on the frequency span/div switch.? I thought there was one missing on the bandwidth res switch as well, but it looks like there is only one contact finger (4 fingers) on that one normally.? There is a spot for another one to go, but the rivets are brand new.? Unlike on the ones that are broke where it is clear they have been ripped out.

The contact fingers are roughly 0.25" wide and 0.5" long.? I found this finger stock by Laird Technologies EMI part # 97-521 ().? I think this will work fine.

But as you said, I am more concerned about putting this back together!? I really screwed up taking the double-stacked frequency switch apart.? I started loosening things I didn't need to separate the two switches, when really the way to do it is by removing the e-clip on top of the shaft - I can't believe I missed that... So this is definitely going to be a challenge.? Especially as time passes waiting for the finger stock to come in...

I know this is a long shot, but did HP release any additional info for assembly/disassembly of these switches?? They include a ton of info on the dial drive assembly in the manual, but nothing about the other switches.? Which is annoying because they are a lot more complicated than the mechanical tuning drive!? At least I have the exploded diagrams so hopefully that will help.

Thanks!

-Frank

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