It's too big...

[eccerr0r]

(That's what she said...)

You removed the old capacitor and bought a new one and later realize, it's too big to fit in the space of the old cap... So you make an extension or use the wire on the cap to reach the holes in the board.

Well, ideally capacitor wires need to be as short as possible to reduce resistance. Yes, the excess leads will add to ESR and ESL (inductance) too... both of which are bad.

But how bad is it if you just can't fit that capacitor into the space that was there (like trying to use a 12mm cap where the original was 8mm) and connected extension wires (as short as possible)... Anyone tried this and scoped out how bad the resultant waveform is? And even left it as it is?

[shovenose]

Re: It's too big...

(That's what she said...)

You removed the old capacitor and bought a new one and later realize, it's too big to fit in the space of the old cap... So you make an extension or use the wire on the cap to reach the holes in the board.

Well, ideally capacitor wires need to be as short as possible to reduce resistance. Yes, the excess leads will add to ESR and ESL (inductance) too... both of which are bad.

But how bad is it if you just can't fit that capacitor into the space that was there (like trying to use a 12mm cap where the original was 8mm) and connected extension wires (as short as possible)... Anyone tried this and scoped out how bad the resultant waveform is? And even left it as it is?

I've done it, never had a problem. I have tried it in PSUs only and not in something sensitive like a mobo though.

[eccerr0r]

Re: It's too big...

I'd imagine both motherboard and PSU have similar problems with ESR/ESL...

I ended up doing the "long legs" on my Antec SP400 along with an undersized capacitor (with better ESR than the broken Fuhjyyu's) and though it works I never scoped out how bad the signal was... I better check...
(the pi filter was source - 1mF (8mm) - inductor - 1mF (8mm)- output, and due to space and available parts it ended up being source - 1mF (12mm diameter, 20mm off the board using the leads that came on the capacitor when new) - inductor - 470uF (8mm, salvaged from something else) - output -- this is very bad -- but it'll have to do until I get proper sized parts, both in capacitance and physical size...

It works though

[turbozutek]

Re: It's too big...

When I was young and didn't know any better I repaired some motherboards (early P4) with the capacitors standing over 3cm proud from the motherboard. I couldn't get a soldered on heat-sink off the back, so had to solder from above and access meant the caps sprouted out like mushrooms from the board.

Worked perfectly for many years, but I guess it's all down to the design of the board and your luck!!

Chris...