Xbox 360 with blown caps

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Been given an Xbox 360 to fix that has blown caps (the big ones near the gpu/cpu heatsinks).

THERE ARE:
14 Rubycon 6.3v 820nf mfz 105deg 8mm dia
9 Rubicon 16v 1500uf mcz 105deg 10mm dia

Done a bit of reading here and the suggestions have been to replace with Rubycon MCZ, Nichicon HZ or HN but i'm buggered if I can find any.

then I came across this thread:
https://www.badcaps.net/forum/showthread.php?t=21540
https://www.badcaps.net/forum/showthread.php?t=13542

The local electronics store have a really bad range and crap "suntan" brand.
I'm in Australia so the only options as far as im aware are:

http://australia.rs-online.com/web/
http://au.element14.com/ (free delivery for online orders in December)

So over to the professionals......what is my next best alternative? I know I could order from here, but postage from the US takes a while.

Thanks
Ashley.

[momaka]

Re: Xbox 360 with blown caps

Suntan may not be good so I don't suggest you use them.

You can safely replace the 6.3v 820uf Rubycon MFZ caps with any of the following polymers:
2.5V 820uF Sanyo SEPC,
2.5V 820uF United Chemicon PSC,
2.5V 820uF Nichicon FPCAP R5 and E5 series
These will also likely work: 2.5V 820uF Nichicon FPCAP R7 series and 2.5V 820uF Fujitsu FPCAP RE series.

As for the Rubicon 16v 1500uf MCZ, you can use:
Rubycon MCZ (obviously ), Nichicon HN, Panasonic FL (you won't find them for sale anywhere but if you do find them on a motherboard, they will work), and Sanyo WG. <--- all of these should be the same 16V, 1500uF rating.

I'm not sure if the Xbox 360 can take polymers in place of those 16v 1500uf caps, but it probably will. If you feel experimental, use 16V 330uF or (preferably) 470uF polymers. United Chemicon PSC, Fujitsu FPCAP RE series, and Nichicon FPCAP R7 series are among some of the choices.

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Re: Xbox 360 with blown caps

Thanks Momaka.
Definitely not touching suntan, some nasty stories are online.

I had already decided to go for Polymers to replace the MFZ's (with Nichicon R7)
I'll take your advice and use Nichicon HN for the others. Not feeling too experimental.

Now I have a question that comes from your poly recommendations if I were to get experimental. How come you suggest using such low capacity here (1500uf vs 330/470) but for the 820's you suggested the full 820? I have read a bit on here that people suggest using around half the capacity when switching to poly due to the faster discharge rate of these.

[mariushm]

Re: Xbox 360 with blown caps

The capacitors are connected in parallel so that the ESR is reduced to a very low value.

Electrolytic capacitors have an ESR that varies with the size and capacity value of the capacitor.. bigger capacitors usually have lower ESR.
For example, that 1500uF 6.3v MCZ may have 0.08 ohm esr while a 470uF 6.3v electrolytic may have 0.15 ohm.

The xbox doesn't need 1500uF capacitors, it may only need 470uF per capacitor, but it's just that value that was the best compromise between big enough capacitor size and low enough esr for each invidual capacitor. Then the designer goes even further by putting several in parallel to reduce the ESR to an even lower value.

Polymer capacitors have much lower ESR from the start - even a 330-470uF 4v polymer capacitor can have less than 0.01 ohm esr. For example, a Nichicon LE 560uF 5v capacitor has 0.005 ohm (5 milliohm esr) :

[momaka]

Re: Xbox 360 with blown caps

Now I have a question that comes from your poly recommendations if I were to get experimental. How come you suggest using such low capacity here (1500uf vs 330/470) but for the 820's you suggested the full 820?

It's just based on what I have seen in computer motherboards and other Xbox 360s.
IIRC, the newest board version of the Xbox 360 (not the slim one, though) comes with 2.5V 820uF Sanyo SEPC and/or Chemicon PSC polymer caps in place of those 6.3V 820 uF Rubycon MFZ and Nichicon HNs, so that's how I know those will work for sure.

As for the 330/470... many computer motherboards will have 3 to 5 of these on the CPU VRM high side. The Xbox 360 slim also uses (IIRC) 4x 16V 470uF polymers for the CPU/GPU VRM high side. Based on that, I think the old Xbox 360 will work fine too. The VRM circuit for both are similar, as are all CPU/GPU VRM circuits in general (and by VRM, I actually mean a buck circuit). In many cases, this is actually why the half-capacitance "rule" works. And I say "rule" because it is actually more of a general guideline than a rule. You can often go higher or lower in capacitance without ill effects, of course all depending on how many caps there are in the buck circuit.

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Re: Xbox 360 with blown caps

Got it,thats really helpful.
Thanks guys.

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Re: Xbox 360 with blown caps

The caps are on the way.
I'll update with pictures and results as I go along.
Also planing to make a few tweaks to the cooling to prevent anything like this happening again.

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Re: Xbox 360 with blown caps

About to start removing these....

[momaka]

Re: Xbox 360 with blown caps

You'll need a tough iron for them. 50W or more preferable (or else you'll need to preheat the board well). Make sure to put lots of solder on the tip of the iron and also add some flux to the pins of each cap. This will greatly help with the heat transfer. I've tried many different methods to remove caps from these boards (hot air only, hot air + iron, preheat + iron, Hakko 808 desoldering gun) - none of which worked too well (the Hakko 808 was okay when used as an iron). The best and easiest method really is just with a temperature controlled soldering station with a chisel tip and lots of solder on the tip and fluxed pins on each cap. It's not required to have a soldering station (you can do it with a regular iron too), but it definitely makes the task easier.

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Re: Xbox 360 with blown caps

Yeah thanks thats what I used, Hakko 936 clone at about 420 deg C. some flux and solder to create a larger heat bridge to the board and the leads. Then just ease out one leg at a time.
They are all out now.
One thing strange i noticed was a few of the leads were loose in the board. Either a bad solder job from the factory or perhaps the joint had become hot and brittle when this thing overheated at some stage.
I should get time to put in the new caps later this week.

[kc8adu]

Re: Xbox 360 with blown caps

somebody do an oven reflow with the caps still on the board?

[momaka]

Re: Xbox 360 with blown caps

^ Most likely. I've never seen Xbox 360 caps fail on their own or due to clogged fans. It takes a LOT of heat to make them bulge. Hope the small caps didn't die.

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Re: Xbox 360 with blown caps

Maybe a Towel trick? this thing still had the warranty sticker intact before I cracked it open.

[Krankshaft]

Re: Xbox 360 with blown caps

These old units are timebombs waiting to happen the GPU is way too inefficient produces too much heat and the constant thermal cycling cracks the BGA balls connecting it to the board. Heat is also another contributing factor as insufficient air flow due to clogged heatsink fins (that you can't clean thanks to Microshaft's warranty sticker) hastens the boards demise.

The newer slim 360s have the CPU and GPU on one die and run way cooler. They also finally put a heat spreader over the dies.

You can see the comparisons here:



If the GPU balls are cracked neither the towel trick, bake it like a batch of brownies, or the board warping and destroying X clamp hack will produce any lasting results. You'll need to either reball or reflow.

That looks like an early generation console as well since the GPU heat sink was later updated to include a heat pipe coming out of it which would then terminate on some radiator style cooling fins.

The earlier consoles were known for popping caps (but I believe they were a bad batch of Nichicons) replace them and give it a try but don't get your hopes up if it still doesn't work.

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Re: Xbox 360 with blown caps

Just Had the chance to pop these in.
I'll test it out tonight.

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Re: Xbox 360 with blown caps

......and she lives!

[momaka]

Re: Xbox 360 with blown caps

Congrats!
Now you won't have to worry about the caps popping again

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Re: Xbox 360 with blown caps

Thanks!
Also made a few cooling mods while I was at it if anyone is interested.
The plastic will help the air to be drawn through the heatsink fins better. Also re-purposed an old P3 CPU fan after giving it bit of a trim and tapping into 12v source just under the main power connector. It sits on top of the extra GPU heatsink on the heatpipe. It also helps to draw in some cool air from the small air vent in that part of the case.
So far so good!

[momaka]

Re: Xbox 360 with blown caps

Good.
These Xbox 360s do need some fan mods to help them stay cool. Most of the time, I just modify the fans to run on 9 to 10 V constantly. It makes the Xbox louder, but at least it stays cool.

[dj_ricoh]

Re: Xbox 360 with blown caps

i`m 100% sure that the motherboard from that xbox has seen the inside of the oven :P
you can see the color of the solder going from orange to brown (: