Polymer caps and retro video games

[Paranoid_Andy]

Hello everyone!

I've been doing my best to educate myself on poly caps and when you should/shouldn't use them however my limited knowledge and experience makes me nervous about moving forward without asking the community. I know the ripple effect exists, but have no idea if it would apply to what I'm doing.

I'm aware electrolytic capacitors can last a very long time but I'm looking for a 1 and done solution rather than recapping all my stuff when I'm old and cranky :P

I would like to know if it's possible to cap any of the following items with poly caps.

1. Game consoles:
NES, SNES, Genesis, Sega CD, PC-Engine
Playstation 1/Saturn(have built in power supplies)
This site lists the capacitors used for each console. It may be helpful so I'm providing a link to it:
https://console5.com/wiki/Category:Console

2. Game carts:
NES and SNES often use one or two 22uF 6.3v caps and Genesis/MD often use a 47uf 16v

3. Arcade boards

I would place my electronics ability at around 4/10 so feel free to simplify things for me. I won't be offended.

Thank you for any help at all as I'm very interested in this.

[stj]

Re: Polymer caps and retro video games

arcade boards should not use polymer because most of the caps are in the audio circuits.

playstation can use tantalum instead of electrolytics on the system board - the psu needs electrolytics.
infact unless your dealing with over 470uf there is no point looking at polymers at all.

[rugger]

Re: Polymer caps and retro video games

There are modern equivalents of electrolytic capacitors from good brands for ANY capacitor you would find in any of the consoles you mentioned above.

Only time I would suggest using polymer capacitors would be to replace the very low ESR caps that appeared on some later motherboards (Pentium 4 and Athlon XP motherboards) that are no longer manufactured.

Otherwise there is always an equivalent to what you are looking for on the standard electrolytic market.

[Paranoid_Andy]

Re: Polymer caps and retro video games

Hey thanks for the reply Stj.

That makes sense about the audio circuits and the PSU needing electrolytics.

Is there an explanation somewhere about why over 470uF doesn't need polymers? I ask because I've seen a few posts from people that have done recap jobs using polymers for caps with much lower ratings so I'm wondering why.
Here and here:
https://forums.nesdev.com/viewtopic.php?f=12&t=20230

https://www.arcade-projects.com/thre...acement.12296/

Hi Rugger,

I'm wondering, do you mean there are other types of solid state caps besides polymer that can do what I need?

My main goal is to find a solution that will be permanent or at least last the rest of my life. I don't want to have to recap my consoles/games ever again, if that's even possible.

Thank you for the replies!

[stj]

Re: Polymer caps and retro video games

i meant under 470 doesnt need polymers - mostly because you can use tantalum.

[rugger]

Re: Polymer caps and retro video games

Hi Rugger,

I'm wondering, do you mean there are other types of solid state caps besides polymer that can do what I need?

My main goal is to find a solution that will be permanent or at least last the rest of my life. I don't want to have to recap my consoles/games ever again, if that's even possible.

Thank you for the replies!

Nah, I mean that you shouldn't be changing from standard electrolytic caps to different types ... in virtually all cases.

In fact, if you were to pull the vast majority of the capacitors out of things in your collection, you are likely to find that they are all still good, with few exceptions (to the specs of the original capacitors of course, modern electrolytic caps tend to be higher performance than those of the 80's and 90's) It would only be devices with particularly poorly made capacitors, or those under high stress where you actually see these capacitors dying.

Just definitely note that solid polymer electrolytic capacitors are not the answer either. They can age and die just like aluminum electrolytic capacitors. Same with tantalums ... they like to randomly short and brilliantly explode.

[Paranoid_Andy]

Re: Polymer caps and retro video games

Thanks for the update guys.

I've heard on several occasions about retro capacitors leaking and drying up on these 30-40 year old consoles but from what your saying it sounds as though that only should be happening if the capacitor is of a lower build quality.

I think my final question is, if you were in my position and you were looking to replace old faulty caps with ones that you felt would last a very long time, what type and brand would you personally go with for the games and consoles?

Thank you again for all the help!

[stj]

Re: Polymer caps and retro video games

well after 40 years any cap will fail - the rubber bung will rot even if nothing else happens.

[rugger]

Re: Polymer caps and retro video games

I think my final question is, if you were in my position and you were looking to replace old faulty caps with ones that you felt would last a very long time, what type and brand would you personally go with for the games and consoles?

Panasonic FR and FS series capacitors will do just fine. Inexpensive and good range and availability.

What is available in your local market may be different.

I'd replace general purpose filtering capacitors with low ESR capacitors where ever I find them.

I would also check and test capacitors before replacing them. Capacitors that look and test fine on circuits that are still working shouldn't be messed with. Changing things on any board with a soldering iron is not risk free. Always a risk of burning things and lifting traces, or putting a capacitor in the wrong way, or making a capacitor change that upsets the circuit.

[rugger]

Re: Polymer caps and retro video games

well after 40 years any cap will fail - the rubber bung will rot even if nothing else happens.

Yet, there are plenty of electrolytic capacitors out there, 40 years old, in good working condition.

[brethin]

Re: Polymer caps and retro video games

It all depends on the item was stored and used, I have a few of the first game consoles that still use tubes for gods sakes and they work fine, or caps don't die they get killed.