Author Topic: 3458a hole drilling  (Read 792 times)

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Offline EE4allTopic starter

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3458a hole drilling
« on: October 07, 2024, 10:52:56 pm »
 I just put the last refurbishing capacitor in the outguard power supply board.  >:D

Yes, I should go bend a proper bracket or 3d print one, but...

 :-DD

 :popcorn:


 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #1 on: October 07, 2024, 11:04:20 pm »
In all seriousness though, if one does this with just a strap, it should be something more akin to thick rubber, so that if the capacitor ever swells, it doesn't start to stress the board. I have seen it like that, for example, in Fluke gear.
 

Online coppercone2

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Re: 3458a hole drilling
« Reply #2 on: October 07, 2024, 11:05:20 pm »
I would just buy a axial cap
 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #3 on: October 07, 2024, 11:33:35 pm »
Naturally.

However, a capacitor that big with wire leads needs to be secured, radial or axial type. HP apparently secured it by adding a piece of thin foam on top, so that the cover would sandwich it to the board. The new capacitor is not that big around, and I don't like just sandwiching things.
« Last Edit: October 07, 2024, 11:37:44 pm by EE4all »
 

Online coppercone2

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Re: 3458a hole drilling
« Reply #4 on: October 07, 2024, 11:40:36 pm »
with axial capacitors you can just put a bead of adhesive under them and its away from solder joints and you can slice it off easily to remove

drilling holes in a 8.5 digit meter is not my style, its both insulting and provocative

plus, in that meter of meters, I think you want the shield of the cap to be as good as possible, and use axial.

you can still fix it with dp270, fiberglass shred and a axial capacitor

Like if I got that from you I would probobly patch the hole lol


you know with a axial cap, the case typically has spot welded lead on it, the negative side. I think there even exist some reverse polarity capacitors that have positive case, for negative rails, so you have the case tied to earth. its like bypassing shielding
« Last Edit: October 07, 2024, 11:51:54 pm by coppercone2 »
 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #5 on: October 07, 2024, 11:54:43 pm »
I checked, and the new capacitor case was floating. I often use the adhesive, but I went the other way. I didn't want to slather adhesive on the 8.5 meter as much as you wouldn't want the hole. I figured it would be provocative, thus the popcorn. Hopefully, nobody is truly offended.

It would be more proper for a meter of this caliber to make a small 3D printed holder, making use of the hole. Something like that I will do at some point.
« Last Edit: October 07, 2024, 11:57:08 pm by EE4all »
 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #6 on: October 07, 2024, 11:59:33 pm »
Ah, I just reread your post, and you were referring to axial capacitor shielding.
 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #7 on: October 08, 2024, 12:18:53 am »
The original was like this. These meters impress me. The decision they made here doesn't impress me, although I haven't heard of any failures due to this.

 

Offline Kim Christensen

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Re: 3458a hole drilling
« Reply #8 on: October 08, 2024, 04:42:13 am »
Perhaps the foam on top was a cushion to prevent the cover from wearing through the capacitor sleeve rather than holding it in place.
ie: The foam would only prevent movement in one axis, so it seems kind of useless for mitigating problems with vibration.
 

Offline EE4allTopic starter

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Re: 3458a hole drilling
« Reply #9 on: October 08, 2024, 03:58:35 pm »
This capacitor is actually on the bottom of the meter, so it hangs down during normal use.

I was not satisfied with the axial capacitor ratings that were available, and is why I went with a radial one. However, I could have done better with it by extending the negative, rather than positive, and giving the capacitor a copper tape jacket (Kapton tape followed by copper), with the extended negative magnet wire then soldered along it. Perhaps I will do that at some point. I have more immediate tests to do though, and this being the outguard supply, not sure it would make any difference.
 

Offline factory

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Re: 3458a hole drilling
« Reply #10 on: October 08, 2024, 07:21:27 pm »
Your right, the axial capacitor choice for 8300uF @ 35V seems poor, nearest from Mouser is 10000uF, choice of just two 85°C caps, either Vishay or CDE/IC. My preferred choice would have been a RIFA/Kemet/Yageo PEG series, but there are none above 5200uF  :--, they are sometimes too big to fit anyway.

David
 


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