3458a hole drilling  - Page 1
Forum section: electronics / repair

author: EE4all
author_rank: Regular Contributor
timestamp: October 07, 2024, 10:52:56 pm
content: I just put the last refurbishing capacitor in the outguard power supply board.Yes, I should go bend a proper bracket or 3d print one, but...

author: EE4all
author_rank: Regular Contributor
timestamp: October 07, 2024, 11:04:20 pm
content: 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.

author: coppercone2
author_rank: Super Contributor
timestamp: October 07, 2024, 11:05:20 pm
content: I would just buy a axial cap

author: EE4all
author_rank: Regular Contributor
timestamp: October 07, 2024, 11:33:35 pm
content: 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.

author: coppercone2
author_rank: Super Contributor
timestamp: October 07, 2024, 11:40:36 pm
content: 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 removedrilling holes in a 8.5 digit meter is not my style, its both insulting and provocativeplus, 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 capacitorLike if I got that from you I would probobly patch the hole lolyou 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

author: EE4all
author_rank: Regular Contributor
timestamp: October 07, 2024, 11:54:43 pm
content: 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.

author: EE4all
author_rank: Regular Contributor
timestamp: October 07, 2024, 11:59:33 pm
content: Ah, I just reread your post, and you were referring to axial capacitor shielding.

author: EE4all
author_rank: Regular Contributor
timestamp: October 08, 2024, 12:18:53 am
content: 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.

author: Kim Christensen
author_rank: Super Contributor
timestamp: October 08, 2024, 04:42:13 am
content: 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.

author: EE4all
author_rank: Regular Contributor
timestamp: October 08, 2024, 03:58:35 pm
content: 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.

author: factory
author_rank: Super Contributor
timestamp: October 08, 2024, 07:21:27 pm
content: 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