# broken legs of good capacitor 330uf 250v,fix?

#### playit

Joined Feb 19, 2020
55
) could anyone tell me an alternative filter capacitor 330uf 250v (2 of them) ,if i dont get a exact values? at my place it difficult to get any computer related small components..and i fi had to buy from mouser etc.. it takes a lot for just shipping!

#### dl324

Joined Mar 30, 2015
12,873
i am so sad i just fixed it and was so happy
The thing is how can you tell if you fixed all of the problems? I worked on several computer power supplies that went into an HP computer system (mid '70s refrigerator sized). We had a lot of tests to perform on them to make sure that everything functioned and that the three would work together.

The first, and only, computer power supply I replaced took months to isolate as the problem. The computer would sometimes crash or hang and it took awhile to troubleshoot. After that, I learned that I didn't want to attempt a repair because I could end up with an unreliable computer.

I didn't throw it away and could probably modify to uses it as a bench power supply that could supply gobs of current, but there's no way it would ever go back into a computer.

#### playit

Joined Feb 19, 2020
55
no i am not gona put it into my pc ever ..just gona use it for my case fans alone.. and it took me a week to identify whats wrong with help of a forum called badcaps .. i got help from there. so when i soldered resistor it just worked up and i spoiled it and rest of the story.. so just want to keep that as my hobby and learning circuit now and if it works i wana use it for my case fans alone

#### narkeleptk

Joined Mar 11, 2019
524
(my solder point tip is bigger (sad).. )
I rarely use anything but hot air and this knife tip, I don't think the solder tip is generally a problem. Just more practice and patience. Like the other poster said, just walk away and come back later. It aint going no where.

#### playit

Joined Feb 19, 2020
55
true..its not goin anywhere.. but damm truly i need a punch bad hihi and oh my solder point is different from this kinda bigger ,it does have tip sharp but hmm it goes big on small part down there ,also i found out i should have used a smaller soldering wire..would have made my work easier ..

#### Janis59

Joined Aug 21, 2017
1,332
Standard methodology for such problem tested on zillions repair jobs all around the russia produced components is such:

1) Take the roughly 2...3 mm thick metal pipe (copper, steel, stainless, any) and make the end sharp, then saw at least 2 or 4 gaps. Now You have a perfect instrument to encarve the small cup-holes without of traumatizing the wire in centrum of that hole. This blade will be centered actually by those wire rest.
2) Next, make the 1 mm deep hole around the lost feet. With scalpel crack the stone (plastics, epoxy, any) around the suffered wire. If hole will be too deep, capacitor may dehermetize, that a cap death. Minimum minimorum is 0.5 mm otherway soldering will be too weak.
3) Then produce the small loop eye over the naked wire of proper diameter, let it goes around the original wire with minimalistic gap, for exaple, o,6 mm inner diameter. Pull it over the suffered wire in the cuphole.
4) Then apply the pure ortho-phosphoric acid droplet and asap solder over. This acid sucks-inward the solder metal actively thus it is only way to warranty that contact in non-touchable space will be good enough. None other kind of fluxes may not do this job so well as this, or may not do at all.
5) Then wash the accid very carefully under flowing water, dry-up fundamentally and flood over with fresh epoxy resin with hardener. Dont forget the last step otherhow the repair job will be sacked after few days of joy.
6) Next day may solder back the cap in Your circuit.

Does it pays so, I am not sure, if cap costs 50 Eur then may be, but if 5 Eur, then better save Your labor to more significant jobs.

#### Tonyr1084

Joined Sep 24, 2015
6,000
) could anyone tell me an alternative filter capacitor 330uf 250v (2 of them) ,if i dont get a exact values? at my place it difficult to get any computer related small components..and i fi had to buy from mouser etc.. it takes a lot for just shipping!
The CRITICAL number is the 250V. If you get a lower voltage cap you can and will blow it up. In my early early early days of messing with electronics I took a 12 volt transformer and a rectifier, one of those big fin types, and connected it to a car radio. The radio played but had a HORRIBLE hum to it. Someone told me I needed a filter capacitor on it. So I took a 16 volt electrolytic cap and put it across the DC from the rectifier. Made virtually no difference. So I thought maybe it goes before the rectifier. That didn't work either. So I thought maybe it belonged on the transformer primary (110 volts AC). The instant I switched it on the cap blew like a cannon ball out of a cannon. Two reasons why it blew up - first - I exceeded its voltage. Second, it was an electrolytic and was not meant to handle reversed voltages.

So if you replace it with other caps you might find elsewhere, they MUST MUST MUST be rated at least 250 volts. Given that the ones you broke off are electrolytic, I'd recommend the same type (electrolytic). The other number, the 330µF is the capacity, or the ability to store energy. Lower numbers will hold lesser capacity - hence the name capacitor. Higher numbers will hold higher. You can probably get away with a 470µF cap in that position, but it will be physically larger and might not fit. A lower value, such as a 200µF will be smaller and will likely fit, except the lead spacing may be off. But going with a lower value means the Power Supply (PS) will not be able to supply as much current before things start to hum. Since you're planning on only powering fans I don't think a smaller cap will cause you much grief. But if ever in the future you want to use it for a higher powered project, the small caps may become an issue.

But again I must reiterate the capacitors working voltage. DO NOT GO LOWER THAN WHAT WAS THERE! Disaster awaits if you do.

#### Janis59

Joined Aug 21, 2017
1,332
Hardly wonder about 250V except is specified for AC. Because the 220V network have 314 Volts peak-to-peak thus the minimum safety class must stand the 350 Volts for ripple-killing electrolytes.

#### Tonyr1084

Joined Sep 24, 2015
6,000
Without knowing what voltage is applied and where, if the OEM (Original Equipment Manufacture) used a 250V cap there was a good reason for it. I wouldn't go below that voltage no matter what reason one might have.

Joined Jan 15, 2015
5,935
The thread starter called out an ATX PSU. Just about every ATX PSU schematic I have seen looks the same on the mains front end. They look just like this:

Note C5 & C6 which are the caps in question and about the only place anyone can get bit (a big shock) is in that area. A Google of ATX PSU Schematic will bring up dozens of these schematics and about95% or more all use the same front end design. Additionally consider the tolerance for caps like this so the only real matter of importance is the working voltage maximum. That's about it and about all there is to it.

Ron

#### playit

Joined Feb 19, 2020
55
wow..so much help in this forums ..so cool i am so happy i am going to learn so much in this journey ,by the way i got 330uf/200 volts filter capacitor.. it wasnt available for 250v..and the shop guy said it will work .. and when before i was checking the voltage each capacitor gave 160v reading..so hmm i am afraid but stil wana give a try but it will take time according to less equipment and my soldering skills lol..

#### playit

Joined Feb 19, 2020
55
Standard methodology for such problem tested on zillions repair jobs all around the russia produced components is such:

wow! really! i never found any post regarding to fix a amputated capacitor in whole of internet till now.. oh my goodness... really i would love to see a youtube video on that.. do you do that.. i thought the capacitor would be expensive but i just got a cheap one..dont know how long will it work ,its not a good brand .so its cheap ,but still wil keep the broken capacitor legs with me ,may be one day i wil try to fix in the methods you have said ,if you have done that would you please put a video on that ?thanks

Joined Jan 15, 2015
5,935
Depending on your location and mains supply voltage and if the caps are configured like the drawing I posted they should work. I would be more comfortable with the higher working voltage rating. Entirely your call. I normally recommend replacing parts with like items.

Ron

#### MisterBill2

Joined Jan 23, 2018
8,808
In my book, computer power supplies are a throwaway. Not worth the time and bother to repair when you can get a new one for around $20. I am not sure what kind of supply you get form$20, at least in the US. Possibly an unknown brand tabletop supply for a laptop or charging a cell phone, but not an OEM product, for certain. And even more certainly, a temper has no part of any service effort. Get a smaller tip for the soldering tool and learn how to keep it in the correct shape. Good soldering is much more than just important, it is VITAL to making electronic things work.

#### playit

Joined Feb 19, 2020
55
hi i need help, i put new filter capacitors.. i get only 5vsb volt.. at R23 resistor ..only one side gets 16v but not to other side which is joined with jumper..last time when i fixed it..it worked but tried something else and broke it.. now i tried to do the same and i get only 5vsb as before.. guide me..thank you

Joined Jan 15, 2015
5,935
How are you trying to start it? If you are getting 5 volt SB apparently something is working.

Ron

#### playit

Joined Feb 19, 2020
55
its with switch ,its on in psu already, i put in plug and on it ,then i put psu tester ,i see only 5vsb.. i checked the circuit vsb supply..it gives 5v..

Joined Jan 15, 2015
5,935
What I am getting at is to start an ATX PSU with any rear switch in the ON position you short the only green wire in the main connector harness to ground. The green wire is held logic high using a pullup and placing it at logic low, ground, is the PS_ON command and starts the PSU.

Ron

#### playit

Joined Feb 19, 2020
55
so now what to check? by the way..i checked transistors at the transformers in psu,they are not reading normal as before they did

#### playit

Joined Feb 19, 2020
55
this is a mercury 400w psu,just want to make it work ,so i can use it for case fans for the coming summer

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