Noob needs help choosing replacement caps (experts please help)

[Pentium4]

Re: Noob needs help choosing replacement caps (experts please help)

I've seen quite a bit of GP caps in PSU's (on the main rails), and usually with no PI coils, or very small ones. They're usually 105C rated though, not that I would ever want to use them...

[Stevevil]

Re: Noob needs help choosing replacement caps (experts please help)

um... I'm not sure but to recapitulate what I'm hearing, my choice of general purpose (regardless of the close specs) are the wrong choice for this type of circuit? It's definitely a monitor power supply. I searched for about 2 hours last night on various sites to find those listed, I'm not sure where I can find closely matching caps that aren't GP (the only other type I saw listed were "automotive" and like I asked above, I don't know what that means unless it's rated for 12v DC.)
At this point I am really afraid to pick these out myself. I would really appreciate anyone who is willing to find me links to suitable caps (if these aren't going to work). I've had this thing disassembled for over a month and I really didn't know it would be so difficult to find the right parts. I'm pretty sure I can manage the soldering part (I've fixed some motherboards before) but I guess this is why electronic shops charge so much (for the knowledge it takes to find correct parts without a schematic). One thing I had to consider was if I could buy just one or a couple (mouser had minimum orders on some caps and so did digikey).
I so want to get this thing fixed.
Can anyone help?

[Pentium4]

Re: Noob needs help choosing replacement caps (experts please help)

The ones we picked out are good, we're talking about general purpose caps that are meant for basic circuits like a home radio or something, that are rated at 85C (don't handle heat well at all) and have very poor ripple specs. Don't worry about the capacitors we all chose for your monitor, we just got a little off topic

[Stevevil]

Re: Noob needs help choosing replacement caps (experts please help)

OK, whew. Thought I put that work in and messed it up.
I didn't even notice that one was 300 min. Yikes.
So you feel 1.9A is close enough to the original ripple of 1.75 to not matter, I guess.
-
Petes CA, you've got a ton of posts, do you also agree with my final choices (going with the 2nd on the cap with two links) and the replacement P4 helped me find?

Man, I'll be so excited to get these ordered.

And why does that one say Automotive? No one has told me what that designates.

[Pentium4]

Re: Noob needs help choosing replacement caps (experts please help)

OK, whew. Thought I put that work in and messed it up.
I didn't even notice that one was 300 min. Yikes.
So you feel 1.9A is close enough to the original ripple of 1.75 to not matter, I guess.
-
Petes CA, you've got a ton of posts, do you also agree with my final choices (going with the 2nd on the cap with two links) and the replacement P4 helped me find?

Man, I'll be so excited to get these ordered.

And why does that one say Automotive? No one has told me what that designates.

1.9A over 1.75A is better, that means it can filter more ripple than the previous capacitor without getting overloaded, and since it is rated higher, for the work it's doing it should run more cool. This is important in monitors because even though they don't use a lot of electricity, it's all passively cooled so they can be hard on parts.

[cheapie]

Re: Noob needs help choosing replacement caps (experts please help)

And why does that one say Automotive? No one has told me what that designates.

It means nothing. It's just commonly used in automotive equipment. It can still work anywhere as long as the specs are OK, which they are in this case.

[mariushm]

Re: Noob needs help choosing replacement caps (experts please help)

Digikey uses the "General Purpose" category as a sort of catch-all. It's not what you think it means and what we normally refer when we say general purpose capacitors.

They just put some specific categories besides that catch-all category like "Audio" , "Automotive" and "Motor start" ...

Sometimes the capacitors used for automotive purposes need to have additional certifications (they're more expensive) and they need to handle heat and vibrations better and those series may be able to survive better small bursts of voltage (for example spikes of 30-50v coming from alternators or whatever (i don't have a car so I don't know the exact terms).
If you're really curious, you can just select automotive category and check the datasheets of some random capacitors ... for example some Epcos capacitor advertises up to 40g vibration protection, a Nichicon series says high reliability 1000 hours @ 150c, an UCC series says 5000h @ 125c ... so the trend for these is high temperature and vibration related stuff aparently.

As for audio capacitors, it's a lot of marketing speak in those datasheets... don't get me started.

[PeteS in CA]

Re: Noob needs help choosing replacement caps (experts please help)

OK, whew. Thought I put that work in and messed it up.
I didn't even notice that one was 300 min. Yikes.
So you feel 1.9A is close enough to the original ripple of 1.75 to not matter, I guess.
-
Petes CA, you've got a ton of posts, do you also agree with my final choices (going with the 2nd on the cap with two links) and the replacement P4 helped me find?

Man, I'll be so excited to get these ordered.

And why does that one say Automotive? No one has told me what that designates.

Yeah, I've got the keyboard equivalent of a big mouth. Seriously, your choices, with P4's recommendations, look good.

[Stevevil]

Re: Noob needs help choosing replacement caps (experts please help)

Thanks for the help everyone. I just ordered my caps. I'll update this thread with my results in about a week. Fingers crossed that I don't fry anything changing em out.

[Stevevil]

Re: Noob needs help choosing replacement caps (experts please help)

Replaced the caps (6 caps took me over 2 hours to remove and replace) but I was surprised how well most of my solders went. I'm writing this using the monitor now and it's working perfectly! No artifacts, no problems!
Thank you so much for your help with this project. I'm so stoked to get my IZ3D working again!
I learned quite a bit during this process and I'll be better equipped for my next repair project (maybe I'll finally fix that cap-plagued dell sx240 I've been sitting on for 2 years).
Until next time my friends.

[Pentium4]

Re: Noob needs help choosing replacement caps (experts please help)

Glad to hear you got it working. Good job!