Substitute capacitance

[dungbeetle]

Is it ok to substitute the capacitance either higher or lower if an exact value cannot be found? Is higher better than lower? How much higher/lower can you go?

[Spacedye69]

Re: Substitute capacitance

https://www.badcaps.net/forum/showth...ght=higher+cap

[dungbeetle]

Re: Substitute capacitance

Thank you very much...thats what I needed to know

added: Does height have anything to do with substituting caps other than clearance? If I substitute an 8mm thats 30mm tall with an 8mm thats 15mm tall with the same specs, is that ok?

[starfury1]

Re: Substitute capacitance

Yes it should be ok

Size can,will factor into the specs but if the specs are the same or better your only worry is if its going to interfere with something physically, like heatsink etc
as you said

[dungbeetle]

Re: Substitute capacitance

Thank you for the response. I'm learning as fast as I can

[gonzo0815]

Re: Substitute capacitance

Size does mater, especially the height.
At least the inductance and may be the ESL would be probablably higher compared with a taller cap.
A few mm would probably do no harm, but it all depends from the circuit.

[999999999]

Re: Substitute capacitance

Thank you very much...thats what I needed to know

added: Does height have anything to do with substituting caps other than clearance? If I substitute an 8mm thats 30mm tall with an 8mm thats 15mm tall with the same specs, is that ok?

Unless one is a VERY old cap (the taller one, and I mean over 15-20 years old) it is not likely that the shorter cap has the same specs. It might be same voltage and uF, but different temp or ESR. Generally you would want higher temp and lower ESR from the taller part when possible.

[dungbeetle]

Re: Substitute capacitance

Ok, so the same spec is preferred, or one with higher uf and possibly higher voltage if same cannot be found. Height does matter as it most likely will be a worse spec in one field or another or how could they have made it shorter. I will look at the caps I bought and see where the shorter ones lag behind in their ratings....

[999999999]

Re: Substitute capacitance

Unfortunately it is even more *confusing" when considering caps that have questionable ratings, a higher uF & voltage and low ESR than their can size would suggest when comparing to other major brands.

In other words, if the spec sheet says it's just another competitive, very low ESR cap but somehow it seems they magically managed to put 3300uF/10V (or whatever rating) into a 10mm dia. cap, when the major manufacturers like Panasonic United Chem-Con, NIchicon, all use a larger sized capacitor to achieve same specs, it is usually a sign the smaller cap is cutting corners and best avoided.

[starfury1]

Re: Substitute capacitance

Humm should have paid a bit more attention to the can sizes given
like thats half the height for the same diameter.

Should have stated it better too
As pointed out above, it does depend on the circuit and how the other specs may or will affect it. like ESL etc

So yeah, I stand to be corrected on that.... should have made it clearer

One thing I meant to ask was what brand/series of caps are you replacing and what brand/series are the new ones ?

What are you replacing them on ?

(Photos are always nice)

Some links on capacitors,

basic page on them

link1

ESR ESL page on it

bit more on basics

PDF

bit over the top if your not into electronics but may help
Capacitor ESL/ESR Measurement With Mercury-Wetted Relay

found it so threw it in

Anyway hope these help

Cheers

[dungbeetle]

Re: Substitute capacitance

Thanks for the links and extra info. The reason I asked is that I have a couple of Nichicon 560uf 6.3v caps and on my original order was unable to match them exact so I found some Nichicon 560uf 6.3v U(PL) caps that are supposedly low ESR and also "low profile". I haven't installed them yet but here is a pic as to where they are going to go...

[dungbeetle]

Re: Substitute capacitance

Ok, here is what I got. The 2 Nichicons in the board are 560uf 6.3v 8x20's and the first replacements I got are Rubycon 470uf 16v MBZ or 820uf 6.3 MCZ. But the Rubycons are 8x13's. The Nichicon I have picked up are 560uf 10v with a M(PL) for the identifier and they are 8x20, the same height as the originals. Anyone heard of this series and if so are they any good?

[dungbeetle]

Re: Substitute capacitance

I found the PL's listed in the "Good Capacitor" thread.

[999999999]

Re: Substitute capacitance

The Rubycon MCZ 820uF/6.3V should do fine. Rubycon is one of the exceptions in that they make decent caps with higher density.

[dungbeetle]

Re: Substitute capacitance

Is this one of the few exceptions or... I guess I need a master capacitor chart. Is there one I don't know about ?

[PeteS in CA]

Re: Substitute capacitance

The PL series has been around for nearly 20 years, iirc. It's a good series, but the MBZ and MCZ series are much newer (and also very much lower impedance). Typically, if you compare the value of C in a particular can size for a PL part, the more modern PW series part in the same can will be one or two standard values higher (e.g. PL = 1000uF, PW = 1200uF or 1500uF).

[starfury1]

Re: Substitute capacitance

Gonzo peteS and 9's are far more up to date with the series and whats what with that
Then I so go by what they have said

You were going to use quality caps so thats good

To just summarize it a bit


If you don't have an exact replacement, its usually better to go 1 up maybe 2 going higher can create other issues (such as too much inrush current through other components)
Sometimes its better anyway but does depend a bit on the circuit

Voltage wise, mainly you go up

There is a possible exception here

Sometimes in order to get a lower ESR a less quality higher voltage cap is used.
(maybe sometime the MB maker got a good deal on a stack of lesser quality and so used them through out)

so for a 5 Volt rail with 10 Volt caps, you can get away with using 6V3 good quality low ESR caps.

Important thing is you never use lower voltage across higher voltage
I.E 6V3 across 12Volt rail is a definite no no

its is always best to use quality caps as above or panasonics etc
(see the good cap thread)

Samaxon are probably, (proving to be) the exception to the rule of TW or china made caps
So make a cheaper quality alternative (avail from TC or Big pope)

Sometimes the physical location will be a problem and you will be stuck having to try and source the 8mm diameter in the value you need

but sometimes you use what you can to get the job done here
may not look pretty but it works....I am sure that MB has not been back to will for that problem
mine dont look much better but hasn't missed a beat since the recap
(I got the same pcb in the other box used same caps...my GSC's were all popped and leaking....and yet it was still going, not well thought.. freezing sometimes rebooting)

Ideally you do want them to sit flush as lead length will add a wee bit of resistance.

So yes please read the posts here and make a note of what was used for what MB's
should help you build up a profile on whats what and what to watch out for

HTH

Cheers

[dungbeetle]

Re: Substitute capacitance

starfury1: Thanks for the added info. The more info the better I am going to get some Samxon's too as so far from what I read, they are worth a try. Eventually I will have some from all the good caps list as I like collecting repair parts so I have enough on hand for immediate use. I prefer to use the correct and quality parts so thats why all the questions. I have read a lot of the forums but there is always a question or two that remains. I ordered an ESR meter (still waiting on it to arrive) and got my new soldering equipment so soon I will be on my way.

[starfury1]

Re: Substitute capacitance

No worries....ESR meter is a useful tool to have if you are going into recapping

Me I dont much only when the need arises but others here have almost made a career out of it... and have gone from knowing nothing to being very good recappers

So feel free to ask any question....even if you think its a bit dumb
We all started somewhere and we all had to learn

Does help if you at lest got electronics basics down but you can get away a little with just knowing what to look for and what to replace with
(olden days that would have been known as a valve jockey)

Having good solder skills is a must so practice on junk MB's if you can get your hands on some


As you have probably found its a friendly bunch round here and will offer help when needed.

Cheers and keep us posted on how you go

[dungbeetle]

Re: Substitute capacitance

I've got the electronics basics down alright. I just float from different hobbies to keep life interesting Seems I always like computers the best but need the other hobbies for a break I don't think I will make a career of it but I like to be able to fix my own stuff and maybe a friend or two. Or even get some good deals on thrown out motherboards My soldering skills are ok and I have found when they weren't it was because of using cheap or junk equipment. When my Weller 1002 was working I could solder good. When I used a cheap RatShack solder station, it wasn't. It seemed the tip disappeared in a week or two!! I used to repair Commodore computers many years ago. I knew a guy in the business of fixing arcade machines and he shipped me a bunch of old boards to practice soldering on. In fact, one of my electronic books has a plan to make some kind of goggles that have LED's in the lenses to make a person go into some weird brain state (beta, theta, something like that) like a dream state while awake. Some day I will make them