Is there any downside to using capacitors with higher rated voltage?

[silviasol]

I am fixing sega game gear systems which have capacitors from the early 90's which I guess had to use poor quality capacitors with fish oil(unsoldering the caps actually smell's like fish, lol) to comply with the overseas transport laws back then.  The kit I bought on ebay has higher voltage capacitors, some short research I did shows that only the ohm rating matters so long as the voltage of the cap you are replacing is below the new cap.  Just wondering if there is any benefit if I bought my own capacitors with matching voltage ratings.  It is battery powered if that makes a difference with the voltages fluctuating as they drain.

[james_s]

Generally speaking there is no problem using capacitors of a higher voltage rating. They tend to be physically larger and if you go way too high the ESR tends to be higher but in your case it is no problem at all.

[that_guy]

Too little ESR can be a problem in subcircuits that require some for stability. Eg the output cap on a voltage regulator.

[mariush]

Some voltage regulators (and some other ICs) require a minimum ESR value on the output capacitors, the 1117 linear regulators are a typical example... they recommend using capacitors with at least 0.1 ohm ESR for that series of regulators.

If you use capacitors rated for higher voltage, these are often in bigger can sizes, which means lower ESR, so in some situations the ESR may drop below some safe threshold and then the linear regulator may become unstable.

[Seekonk]

Higher voltage capacitors will generally give longer life.  If getting old stock capacitors on ebay you better get higher voltage caps in order for them to survive without going through the process of reforming.  Stubby capacitors of the same value as tall ones usually have a higher ESR.

[retiredcaps]

The kit I bought on ebay

99% of the capacitors sold on ebay are pure crap or counterfeit.  Yes, there are good sellers on ebay who sell the real item, but it is like finding a needle in the haystack.

Post a link to your ebay auction so we can see what you bought.

Since you live in the USA, for future orders, digikey and mouser are two good reputable distributors to get quality Japanese caps like Nichicon, United Chemicon, Rubyon and/or Panasonic.

[Richard Crowley]

Remember that the situation is different depending on whether you are talking about electrolytic (polarized) capacitors or "conventional" (non-polar) capacitors.  It is quite common to see high (100V) ratings on very small (pF & nF) capacitors because it would actually be more difficult/costly to make lower-voltage rated capacitors (because of small size) and the caps are small enough that nobody wants to bother with using lower-voltage caps.  Plus there is no electrical advantage to using lower voltage caps.

OTOH, electrolytic capacitors depend on some good percentage of their voltage rating to develop the capacitance rating.  In addition to all the discussion of ESR,  there is also the matter that using an electrolytic capacitor with a 2-3-4x voltage rating above the actual circuit working voltage may be expected to not develop the full nameplate-rated capacitance value.  And then there is also the size factor. Higher-voltage electrolytics for the same capacitance rating will, of necessity, be physically larger and may not fit into the space/footprint of the original capacitor.

Apparently advances in electrolytic capacitor design/materials, etc. seem to make physically smaller bodies than the same rating from decades ago.

[james_s]

In the case of the Game Gear the original parts are SMD electrolytics. The replacements are not critical, some of them do depend on having enough ESR or you end up with a washed out picture on the screen but reasonable quality SMD electrolytics tend to work just fine. Going up a step or two in the voltage rating is not going to be a problem here, just don't try using for example 160V capacitors when you only need 16V.

[silviasol]

Ebay auction  http://www.ebay.com/itm/281523193590?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
They seem to be from mouser, just the cheapest version of nichicon or panasonic caps he could find. 

I went ahead and spent 2 hours making a mouser order.  Mine are smd caps instead of caps with leads.  This way no fussing around with making the caps fit inside the case away from other stuff that gets in the way when closing the unit.  Spent the time to get the correct height, lead/pad spacing and pin holes, should work out nicely.  Now to buy more parts game gears.

Remember that the situation is different depending on whether you are talking about electrolytic (polarized) capacitors or "conventional" (non-polar) capacitors.  It is quite common to see high (100V) ratings on very small (pF & nF) capacitors because it would actually be more difficult/costly to make lower-voltage rated capacitors (because of small size) and the caps are small enough that nobody wants to bother with using lower-voltage caps.  Plus there is no electrical advantage to using lower voltage caps.

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

[james_s]

Probably not, at 0.47uF it's probably hard to find electrolytics rated much less than 50V. They'll be fine.

[Gyro]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

If space permits, it is sometimes worth going to a higher voltage rating just to get a bigger can size. The smallest ones are more prone to drying out (hence the difficulty in finding lower voltage .47uF caps). You will often find different life ratings in the manufacturers' datasheets based on whether the can is above or below a certain diameter.

[james_s]

Either way it hardly matters, this is a handheld video game, not mission critical avionics or something. The original dirt cheap crappy SMT electrolytic caps lasted what, 20 years before they started failing?

[Richard Crowley]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

What "advantage" are you seeking?  Is there some problem you are trying to solve?
What sort of "improvement" do you think you could accomplish from "upgrading" the power filter capacitors?
Sorry, but it all seems pretty silly.

[silviasol]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

What "advantage" are you seeking?  Is there some problem you are trying to solve?
What sort of "improvement" do you think you could accomplish from "upgrading" the power filter capacitors?
Sorry, but it all seems pretty silly.

Well I hear that running them on battery power kills the caps faster then running on ac power, is that not true?

Either way it hardly matters, this is a handheld video game, not mission critical avionics or something. The original dirt cheap crappy SMT electrolytic caps lasted what, 20 years before they started failing?

I think they lasted 10-15 years.  I bought it in 2007 and just stuck it in storage because the screen was too dimm, I thought I got ripped off.  Recently I read how people change the caps on them to get them working again so pulled it out of storage and fixed it, and now runs just like new.  These sell for $50 to $60 with the caps replaced and you can get them for $10 each on ebay broken so can make some money on them.

[Richard Crowley]

Well I hear that running them on battery power kills the caps faster then running on ac power, is that not true?

I can't imagine any scenario where that could be true.

Are the caps "dead"?  By what method did you determine that?  Or are you just looking for busy-work?  One of my favorite quotes came from an old IBM mainframe service manual...

Never attempt to repair or replace equipment which is working to the customer's satisfaction.

Or in more colloquial terms:  If it ain't "broke" don't attempt to "fix" it.

[silviasol]

The caps are bad on just about every game gear now.  Just search game gear capacitors, it is a huge issue.  I went to a pawn shop to pick up two of them, they both had bad caps, one no sound and one the screen was dim(like mine).  It was funny because the guy would not go lower on the price until I started to walk out of the store. 

[james_s]

I think I paid more than $10 for mine, I should buy another to have a spare before they get hard to find. Always liked that system, my little brother had one when we were kids. The only problem is the thing ate AA batteries like popcorn. Fortunately modern NiMH cells work pretty well.

[Zero999]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

I'd be more tempted to swap them with film or ceramic but the capacitance declines with bias voltage with some crap dielectrics.

[helius]

I am fixing sega game gear systems which have capacitors from the early 90's which I guess had to use poor quality capacitors with fish oil(unsoldering the caps actually smell's like fish, lol) to comply with the overseas transport laws back then.

Fish oil is non-polar, which would not be of any use whatsoever in an electrolyte. The fishy smell comes from amine salts of boric acid, which usually is present in miniature electrolytics.
Similar rumors surround products like WD-40, which also doesn't contain fish oil despite its smell. Fish oil very rapidly rancidifies (which you will notice at any outdoor fish market) and is therefore not much use as a chemical ingredient.

[james_s]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

I'd be more tempted to swap them with film or ceramic but the capacitance declines with bias voltage with some crap dielectrics.

That would work for some of them, but the Game Gear relies on the ESR for others. I learned the hard way by replacing them all with ceramic and tantalum and ended up with a washed out picture. Actually it could have been the reduction in capacitance with DC voltage, not really sure, but electrolytic worked.

[silviasol]

There are two caps that are .47uf 50v.  No advantage trying a lower voltage on those?

I'd be more tempted to swap them with film or ceramic but the capacitance declines with bias voltage with some crap dielectrics.

That would work for some of them, but the Game Gear relies on the ESR for others. I learned the hard way by replacing them all with ceramic and tantalum and ended up with a washed out picture. Actually it could have been the reduction in capacitance with DC voltage, not really sure, but electrolytic worked.

Oh you have one?  Probably don't need to worry about them becoming rare, there are so many on ebay.  Virtual boy is what to get before it is gone.  I have two right now and looking for more.  The problem with them is a flex cable that comes unsoldered and one or both screens wig out.  It was soldered directly to the board(is that called hot press?) and looses it's hold.  The fact that the cable bends 90 degree's and is only held on by the solder is probably what is killing them.  Also the one I have that works, the other has no power for some reason, has no sound and really bad sound with headphones.  Waiting for my extra long security bit to be delivered to hopefully fix it.  The thing is just awesome though, even though very uncomfortable to use.

[retrolefty]

Well I hear that running them on battery power kills the caps faster then running on ac power, is that not true?

I can't imagine any scenario where that could be true.

Are the caps "dead"?  By what method did you determine that?  Or are you just looking for busy-work?  One of my favorite quotes came from an old IBM mainframe service manual...

Never attempt to repair or replace equipment which is working to the customer's satisfaction.

Or in more colloquial terms:  If it ain't "broke" don't attempt to "fix" it.

 Well that would put the audiophool vendors out of work. 

[james_s]

My friend had a Virtual Boy, I played with it a couple times, never really interested me. It's technologically cool but the display gives me a headache and since I never had one as a kid it's not something I'm nostalgic about. I did have a Game Gear though, spend quite a bit of time playing it back in the day so I picked up another one a few years ago.

[silviasol]

My friend had a Virtual Boy, I played with it a couple times, never really interested me. It's technologically cool but the display gives me a headache and since I never had one as a kid it's not something I'm nostalgic about. I did have a Game Gear though, spend quite a bit of time playing it back in the day so I picked up another one a few years ago.

They are pretty cool.  I actually play my game gear more then my new nintendo switch.  I have the adapter that has the magnifying lens on it, can't play without it.  Looks just ridiculous though, lol.  It is called "super wide gear".

[meeko]

...I have the adapter that has the magnifying lens on it, can't play without it.  Looks just ridiculous though, lol.  It is called "super wide gear".

I've got one of those for my Game Gear, too.  Yeah, makes a big difference in the playability.  It doesn't fit properly with the adapter to play Master System carts; the spring clip hits the adapter.  I can't remember if it cleared the TV tuner...

I never had a problem with it eating AAs, because I mostly used it in the car, plugged into the cigarette lighter, or at my Grandparents' place, plugged into the wall.  If I did want to use it elsewhere, I had the (NiCd) external battery pack, too.  It weighed a ton, and was kind of a pain clipping it to your belt and having the wire trailing up to the unit, but I seem to recall the battery life from it was fairly decent, at least until the cells started to crap out from age/cycles...