REPAIR GUIDE - TurboExpress: Total capacitor replacement chart

[NightWolve]

If you can find them. I found everything in ceramic for my SNES, but they cost more. They used to only cover very small capacitance values, but now you can get them in average values, never as high as aluminum though.

http://www.digikey.com/product-detail/en/C2012X7R1V475K/445-7555-1-ND/2733627

There's one, .70 cents. Seems all surface mount only though. I soldered two of them on, not hard if you prep it.

In the case of the two that you're looking at, I see a size difference. One is smaller than the other, so it's just a matter of space. It's helpful if you measure the spacing where the old aluminum one is and buy one that's about the same length so you don't have to do tricks with extra solder to install them.

[sparkychan]

Like many have said before, thanks to all that helped with the creation of the chart and providing their technical knowledge to this thread. I am going to begin the process of replacing all the capacitors in my Turbo Express. One question I had was how most remove the white epoxy-like substance near the large 100uf  capacitors? I'm having trouble exposing the solder points for the capacitors.

Any help would be appreciated.

Thank you!

[NightWolve]

Yeah, that was hard. I used a fresh razor blade for that.

[thesteve]

sharp knife here

[sparkychan]

Thanks for the replies. Ugh, I think my attempt was too aggressive and may have chipped the component that is concealed by the epoxy. Does anyone know what the component is that is underneath the epoxy?

[thesteve]

its a choke (coil of wire)

[Frank_fjs]

Any reason why I couldn't use a 'Tag Tantalum Capacitor' in a few spots?



I can get them locally for quite cheap, specifically:

4.7uF 35V
33uF  6V

^ Seeing as these relate to audio/video I thought it might be better to use the Tantalums here.

Can also get the '10uF 16V' & '22uF 6V' in a tag tantalum but am not sure if there's a benefit to doing this, what are these caps responsible for anyhow?

I was planning to use standard electrolytic caps for the rest, just for the sake of cost/availability and ease of install.

[thesteve]

yes you can use them, but uprate the voltages on most

[maverick1978]

Does anyone sell ceramic/tantalum cap kits for the TE? - I can find all the radials I need, but searching through other types of caps really confuses me (electronics newbie here, though I can solder pretty much anything)

[thesteve]

i use size 1206 ceramics (they fit well)
a ceramic is non-polarized (can be installed either way)
ceramics handle ripple well (no need to use higher voltage ratings)

[NightWolve]

yes you can use them, but uprate the voltages on most

Hey steve, pretty much every capacitor just needs to be above 16 Volts, correct ? All capacitors could be replaced with 16 Volt or better models as long as the capacitance value matches, right? That is how I have understood things. I mean, 10 Volts comes into the motherboard, the regulator steps the voltage down to 5V for most operations, etc. there is never anything that steps the voltage back up, is there ? Since the power supply is not a more expensive well-regulated one, you do have 13 Volts, not ~10 Volts exactly coming in, but yeah, as long as everything is 16V or above, it'd work fine, right

See, I made the mistake in believing I had to match the voltages exactly as well when I ordered the caps for my Express... But I could've purchased all of them as 16 Volts or above... All that happens with higher voltage rated caps is that you pay more and they're bigger, but as long as the capacitance value is the same, they'll function the same, isn't that pretty much the case ??

ERR: I was asking about a Duo, hence the 10V rated power supply coming in, but same deal with an Express that has 7V coming in... which in that case, everything probably could be a 10V rated cap at the minimum, but probably still better to have all 16V rated ones, eh?

The one real question I'm asking is, could I just buy ALL caps at 16 Volts or what, ALL caps at 25 Volts to avoid this "ripple" concept you're mentioning ?? What is the ONE minimum voltage breakdown rating that I could buy for ALL capacitors on the board ??

[thesteve]

on the duo no step-up, however the express does use 2 inverters producing higher voltages.
check the voltage across the cap before subbing it

[NightWolve]

Aaaaah, OK, so there is a "step-up" in voltage at times, via what you're referring to as an "inverter," hence the max voltage rating that the manufacturer chose matters in such an instance, and you say that is a valid concern when it comes to an Express, but not the Duo. That makes sense. I was thinking, why did NEC put 50V caps over here, then 16V caps over there, when the motherboard operates at 7-10V, why not just get all 16V caps, you know? I figured there's possible spiking or step-up in voltage at times or something.

I answered my other concern about a 3.3uF capacitor for the Duo that's at 50V, that is, real small capacitance values come in high voltages (like ceramics) most of the time, so you don't find 3.3uF at 16V or something, they make 'em mostly at 50V and they're still pretty small for electrolytic aluminum type. Something Red Ghost had said made me think there was a spike in voltage for that 3.3uF, but that's not the case for the Duo as you say; it's just that small micro-farad value caps generally come in 50V ranges like under 47uF. The closer the capacitance value is to the traditional ceramic range for an electrolytic, the more likely it can handle 50V, etc. Seems like.

Well, I think I understand the rest of my concerns now although I'd like to hear more about this "ripple" concept you mentioned and how that should guide the substitution. Danke!

[thesteve]

ripple causes heat
ripple can also damage polarized caps when the discharge current causes a polarity flip internally

[NightWolve]

Hence why AC non-polarized ceramics are better. Gotcha. Well, I had a bad experience when I switched to all ceramic with my SNES, so now I'm paranoid about going that route. Blew $11 bucks and then I switched back to cheap electrolytic anyway....