Nippon-Chemicon electrolytic capacitor from Taiwan. Original? - Page 1
Forum section: electronics / general

author: ARF
author_rank: Regular Contributor
timestamp: October 17, 2023, 01:29:23 pm
content: I am restoring the power supply from the Agilent 54845A and changing the capacitors.I plan to replace the capacitor in the primary power supply circuit 450V 470uF. It just uses a specific type with 4 pins, two of which are for mechanical fixation. There is no problem in buying such capacitors with 10mm snap-in pins, but the capacitor (40mm height and 450/470uF) with 4 pins is not available.The power supply uses 40x40 Nippon Chemicon KMH 450V 470uF 4pins, 22.5mm between pins space.In general, I always buy capacitors only through DigiKey and other similar distributors, since most likely a fake will come from China and this is difficult to prove.I see a great option on Ebay:https://www.ebay.com/itm/153789260112But the pins are straight (and should be bent to snap into place), this is probably a fake. What do you think?

author: RayRay
author_rank: Frequent Contributor
timestamp: October 17, 2023, 08:39:39 pm
content: I think you shouldn't take any chances and only purchase it from reputable sources (such as digikey/mouser/lcsc/newark)When it comes to capacitors, there are a lot of fake ones out there. If the height you need is not available from Nippon (and you don't have enough clearence for taller ones),then see if you can find it in the height you need from a different capacitor brand, or alternatively, solder wires between the cap to the board and glue it sideways somewhere if there's sufficient space.

author: wraper
author_rank: Unknown
timestamp: October 17, 2023, 08:46:00 pm
content: Even standard LXS series come with two terminal types. So this is not indicative of anything. Neither original KMH capacitor is a snap-in type.

author: RayRay
author_rank: Frequent Contributor
timestamp: October 17, 2023, 08:55:25 pm
content: I've just had another thought about this. There are prototype boards available in various sizes, and since you've mentioned only 2 out of the 4 legs are used in practice, you could just get such a board, solder it with wires to the where the cap is suppose to be, and mount the prototype board with standoffs & screws (you'd need to drill a couple of holes for that of course) but this would allow you to use a 2 legged capacitor with ease, which are more common and easier to find

author: thm_w
author_rank: Super Contributor
timestamp: October 17, 2023, 09:17:17 pm
content: The seller looks legit, but, as RayRay is sort of saying, just bodge in a normal 2 terminal cap. Then glue it on.Who cares if its not the original footprint, no one will see it.

author: ARF
author_rank: Regular Contributor
timestamp: October 17, 2023, 11:33:58 pm
content: I just don't like gluing and drilling. I'm surprised that there is no way to determine the originality of the capacitor, even if you cut it open and look at what's inside, it still won't be obvious.The best option that is available in the right package and in a right place is 680uF x 400V. I think 400V is acceptable.

author: thm_w
author_rank: Super Contributor
timestamp: October 18, 2023, 12:23:14 am
content: You don't have to drill anything. Most likely just bend the pins a bit or solder jumper wires, then glue.There isn't much space though, probably not for a right angle cap.I assume you've measure the original one and verified its bad or degraded?

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 18, 2023, 02:03:59 am
content: Sometimes you see those big cans recycled, sometimes as-is, sometimes re sleeved. I'd trust the part already there more unless it's confirmed bad.

author: ARF
author_rank: Regular Contributor
timestamp: October 18, 2023, 10:28:23 am
content: It works, but it is 27 years old.OK, I decided to use this 680x400Vhttps://www.digikey.com/en/products/detail/vishay-beyschlag-draloric-bc-components/MAL229956681E3/12814060

author: RayRay
author_rank: Frequent Contributor
timestamp: October 18, 2023, 11:05:12 am
content: Quote from: ARF on October 18, 2023, 10:28:23 amNot a good choice in my opinion.The general rule of thumb with capacitor replacements, is that in compare to the original, the voltage needs to be either identical or higher, and the capacitance either identical (preferable) or otherwise, within 20% up or down if not possible to find.I wouldn't replace a 450V/470UF cap with 400V/680UF due to the above.

author: ARF
author_rank: Regular Contributor
timestamp: October 18, 2023, 11:27:01 am
content: This power supply doesn't have any PFC block, so the voltage on this capacitor will be 230V*1.42 = 326.6VAs for the higher starting current, replacing 470 with 680 is not so significant.

author: RayRay
author_rank: Frequent Contributor
timestamp: October 18, 2023, 11:49:52 am
content: Okay, good luck.You have another option though (for an extra 10mm height):https://www.digikey.com/en/products/detail/cornell-dubilier-electronics-cde/383LX471M450A052/2256666

author: ARF
author_rank: Regular Contributor
timestamp: October 18, 2023, 11:57:56 am
content: This power supply is installed close to the case wall inside the oscilloscope and the protruding capacitor will not allow the power supply to be screwed on. I actually looked at all the options and it's either 390x450V or something 400V.Thank you. My original question was about that capacitor from Ebay, maybe someone would recognize it and say that it is the original.

author: thm_w
author_rank: Super Contributor
timestamp: October 18, 2023, 09:42:13 pm
content: Quote from: ARF on October 18, 2023, 10:28:23 amHave you measured its ESR and capacitance?