Hi, cand i replace SNES smd caps for ceramic/eletrolytic higher voltage ones? - Page 1
Forum section: electronics / repair

author: OverclockVintage
author_rank: Contributor
timestamp: November 17, 2021, 10:06:15 am
content: My Super Nintendo is the RGB-01 model, and i want to replace the c35 that is a smd 330pf, and add the ones that came without c22 330pf c57 220uf c11 82pf, i would then use for the c57 an eletrolytic 16v one, and the others for ceramic 50v ones. Is that all right? Thanks.

author: Zero999
author_rank: Super Contributor
timestamp: November 17, 2021, 11:33:35 am
content: Yes, the voltage rating is the maximum. If you measured the voltages on the capacitors, you'll probably find they're already much lower, than their ratings.Anyway, why are you replacing the capacitors? I hope you know that it's generally a bad idea to just blindly replace all of the capacitors, in something which works, except for some ancient wax and paper capacitors, in appliances which contain glassware.

author: OverclockVintage
author_rank: Contributor
timestamp: November 17, 2021, 12:09:12 pm
content: Well i am getting color bleed mostly on the blue color and second on the red and third on the light orange color. I know the trimmer is defective because nothing changes when i turn it's dial. I've already reflowed with the soldering iron all the legs of the ppu1 and ppu2.

author: OverclockVintage
author_rank: Contributor
timestamp: November 17, 2021, 02:41:50 pm
content: Though i only mentioned replacing the c35, the other three ones it came without, though it is regular to come without some few. But coincidentally i was going to replace all the eletrolytics but one(the 2.2uf one).

author: factory
author_rank: Super Contributor
timestamp: November 17, 2021, 03:33:20 pm
content: Quote from: Zero999 on November 17, 2021, 11:33:35 amMore modern stuff from the 80's & 90's can have problems too, particularly if the PCB is multilayer, as the seals in old caps sometimes fail, then the electrolyte seeps out and rots the traces & vias. The leakage is not always obvious until the parts are removed. Even well known quality cap brands such as Panasonic & Rubycon are affected, I've replaced loads over the years at work and had to deal with damage caused.I've even seen unused old stock parts leaking this way at work (since thrown out).The problem is it can be difficult to find out what devices are affected.David

author: Zero999
author_rank: Super Contributor
timestamp: November 17, 2021, 04:52:10 pm
content: Quote from: factory on November 17, 2021, 03:33:20 pmYou're right, a visual inspection won't pick up all dried and leaky capacitors, but I've wasted a lot of time in the past, blinding recapping equipment, only to find out, it still doesn't work. Get yourself an ESR meter, which can test most capacitors in situ. It can save you a lot of time and money.Quote from: OverclockVintage on November 17, 2021, 02:41:50 pmLow value, non-polarised capacitors, are normally the most reliable. Presumably it's a ceramic disc? Is it cracked? Have you tried measuring the capacitance, with one led unsoldered?As I mentioned above, an ESR tester it very useful, for the larger electrolytic capacitors,

author: OverclockVintage
author_rank: Contributor
timestamp: November 17, 2021, 05:28:49 pm
content: As i have already bought them, i'm gonna just replace them, capacitor age so i'm gonna just replace them all and hope for the color bleeding to get fixed by that, the c35 i acidentally touched it with the hot soldering wick and it sparked, so that's why i'm gonna replace it also to be sure, despite that the snes is working the same as before though.

author: factory
author_rank: Super Contributor
timestamp: November 17, 2021, 07:41:59 pm
content: Quote from: Zero999 on November 17, 2021, 04:52:10 pmIt was more a general comment given the age of the device in question, I do have a SNES but haven't used it for years, my main interests are in older radios & test gear, 1970's or older which are less likely to use multilayer boards, I usually only change the caps if they test bad, or are leaking in those. The more modern stuff concerns me more, due to the potential for PCB trace damage.I agree re-capping the electrolytic caps probably won't fix the fault and if an error is made can cause more problems.I do have an ESR meter, results are mixed as it often complains the caps are in-circuit, once removed for testing they can give misleading results due to the heat from soldering, checking the ripple voltage can also find open caps.As for work, some equipment was known for high rates of cap seal failure, changing them wasn't really an issue as there weren't too many and if your removing them to test, then they may as well get replaced, cost to replace was peanuts compared with a potential warranty claim.David

author: OverclockVintage
author_rank: Contributor
timestamp: November 17, 2021, 09:35:24 pm
content: Zero999I realize now that you mean the disc of the trimmer, well i think it's probably broken, it is a 20pf trimmer, i don't even know how is that i still have color with it broken, it turns the dial loose, it does feel like it's broken on turning it. I don't have the ESR tester but i am really towards getting one soon.

author: james_s
author_rank: Super Contributor
timestamp: November 17, 2021, 11:42:38 pm
content: While I generally don't recommend shotgun replacement of capacitors, surface mount electrolytics are another matter, I have worked on many devices where they have leaked and made a big mess of the board, making me wish somebody had replaced them all.Do be careful blindly replacing electrolytic with ceramic. Multilayer ceramic chip capacitors lose a substantial amount of capacitance when they have DC across them and the ESR is also much lower than the old electrolytics so in some cases a device will not function properly with ceramic. It takes some knowledge of the circuit to determine if you can put a ceramic cap in there.

author: OverclockVintage
author_rank: Contributor
timestamp: November 18, 2021, 08:14:31 am
content: The ceramic will be to replace only micro smd ones (i realize now i've said before smd meaning micro smdi've should have specified), all the eletrolytic ones i will replace with eletrolytic ones, and one of the micro smd also with an eletrolytic one.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: November 18, 2021, 11:36:02 am
content: simple rulethe replacement is greater than or equal to the replaced cap's rate of voltage and capacitancebut the latter must not get straight if freq is considerably greatly involved on that point

author: OverclockVintage
author_rank: Contributor
timestamp: November 18, 2021, 04:59:25 pm
content: You mean that it might not be good to replace micro smd with an eletrolytic?

author: TimFox
author_rank: Super Contributor
timestamp: November 18, 2021, 05:32:00 pm
content: Please clarify what you mean by "micro smd". Are you referring to surface-mount ceramic capacitors?

author: OverclockVintage
author_rank: Contributor
timestamp: November 18, 2021, 05:33:52 pm
content: Yes exactly.

author: james_s
author_rank: Super Contributor
timestamp: November 18, 2021, 06:37:27 pm
content: Why would you replace surface mount ceramic capacitors? It is technically possible for them to fail, I've seen one that was shorted once or twice in my life, but broadly speaking they do not wear out. The only capacitors that you should consider replacing due to age/use are electrolytic.

author: Zero999
author_rank: Super Contributor
timestamp: November 18, 2021, 07:08:12 pm
content: Quote from: OverclockVintage on November 17, 2021, 09:35:24 pmNo, I didn't know it was a trimmer capacitor. I forgot it was a surface mount capacitor, as per the first post and assumed it was ceramic disc.Please post a picture of the board, with the parts highlighted, so we know what sorts of parts they are and whether they appear to be in good condition.It's generally advisable to replace capacitors with the same type, even if the voltage rating is higher. Ceramic capacitors behave differently to electrolytics. They have a lower series resistance, but the larger values can be subject to saturation, i.e. the capacitance falling, as the voltage increase, beyond a certain point.

author: OverclockVintage
author_rank: Contributor
timestamp: November 18, 2021, 10:47:14 pm
content: james_sI'm not going to replace the ceramic with eletrolytic, it's just that the snes came without this micro smd that is the c57, in the schematics it is a 220uf one, so i could only find an eletrolytic to put in it's place, while the other one that is actually the c32(i've said before c35 by mistake) i am going to replace it with a regular ceramic disk shaped capacitor.Zero999Well, everything looks quite good actually, but the trimmer i know it's defective because it does nothing to the colors when i turn it, and it should, next time i open it i'm gonna see if i take some pictures to show the current state of it.

author: OverclockVintage
author_rank: Contributor
timestamp: November 22, 2021, 12:08:59 am
content: Update: Recaped, and the image improved quite alot, but the color bleeding is still there kkkkkk. Well the improvement was actually quite remarkable, really. Also the schematics that i've had where different actually, and c57 and c11 where different caps on mine, so i leaved it alone, also about the c32 i've kept the original, also my mistake the c32 was actually an 0.1uf. The replacement caps are mostly if not all some really cheap brand ones, though they are all rated for 105cº. I wonder if the color bleeding has to do with the model of mine not being 1chip.