A couple of weeks ago, I repaired a 2003 Microsoft Xbox for a friend of mine – a very lovely and rather rare green crystal limited-edition Xbox with a translucent case. The symptoms were that the power button didn’t work, but the console could still be powered on with the eject button – a pretty minor issue, but one indicative of bigger underlying problems that will likely only get worse with time.
The original Xbox suffers from a potentially fatal issue: it uses a 1F 2.5V supercapacitor instead of a coin-cell battery to maintain the backed-up RTC, which isn’t a problem in itself, however the part used in earlier units typically fails and leaks a corrosive electrolyte which can cause serious damage to surrounding components and to the board itself.
Apparently, all board revisions except for the later v1.6/1.6b boards are susceptible to supercapacitor leakage, which can cause serious problems (including weird issues with the disc drive and, funnily enough, the power button not working) – the capacitor should therefore be removed, its remnants cleaned up, and replaced.
It is difficult to confirm the board revision as the mainboard has no markings, but it is possible to estimate it from the manufacturing date and serial number – this unit was made in China in October 2003, which means that this is likely a v1.4 mainboard and confirms that it requires replacement of the supercapacitor.
Not only that, but the Xbox is a victim of the capacitor plague of the late 1990s to mid 2000s, meaning that other electrolytic capacitors in the system (typically the CPU / VRM capacitors on the mainboard) are also common failure points.
I started off by dismantling the Xbox to see what was going on inside – I’ve both repaired and upgraded my own Xbox in the past and it’s pretty easy to open up. With the hard drive caddy removed it was immediately obvious that the CPU capacitors had failed, shown in the image below by the bulging and brown crust around their top vents.
With the DVD-ROM drive removed I got my first look at the entire mainboard, and it was clear that all of the CPU capacitors had failed and that there was quite a lot of leakage around the RTC supercapacitor too.
The supercapacitor was pretty easy to remove with my vacuum desoldering station, and the contamination to the board around it and resulting corrosion was pretty evident – the electrolyte is a mild basic so I cleaned off the area with some white vinegar to neutralise, followed by some 99.9% IPA to clean.
Even cleaning carefully, three components came off, the pads underneath them were completely gone: R7G1 (1.1kR 1% 0603), R7G2 (2.94kR 1% 0603), and Q7G2 (MMBT3904).
I had replacements in stock for Q7G2, but the resistor values for R7G1 and R7G2 are very specific non-standard values, and based on the schematic this is necessary to drive Q7G2 properly. It would also take time to rebuild the missing pads.
I therefore decided not to fit a replacement supercapacitor and to leave the charge circuit alone – it’s possible to leave these out on board revisions earlier than v1.6/1.6b and the system should still work fine, it won’t keep the date/time when mains power is lost but the supercapacitor only keeps this for about three hours anyway apparently, so it’s not all that useful. Most modern custom dashboards also use an NTP server to synchronise with internet time anyway, so it’s even less necessary if you’re modding yours.
I also decided to replace the CPU/VRM capacitors that had failed as well as several others on the mainboard, including all of the small SMD aluminium electrolytic capacitors near the video connector – these are common, well-documented failure points in other pieces of older electronics where they physically leak and cause board corrosion, and while I don’t think this has affected the Xbox yet, it’s better safe than sorry.
There are several production variants of the Xbox mainboard and PSU, each of which have different electrolytic capacitor values and locations, so take note of which you have. There are commercial capacitor packs available for the Xbox, but I just made up my own by noting the specifications of all of the electrolytic capacitors that I wanted to replace, and ordering a set of high-quality known-brand parts. See my general advice for electrolytic capacitor replacement for more detailed information on the process.
A common Xbox issue is “trace rot” on the underside of the mainboard near the supercapacitor, either caused by electrolyte leakage or factory contamination – damage to these traces causes all kinds of weird issues including the front buttons not working properly and random power problems.
Being a common issue, there are quite a lot of resources online including some very useful “how to” repair guides – I’ve repaired similar damage in the past using my digital microscope so followed the same process here.
First I cleaned suspect areas (dark spots in the solder mask) back to bare good copper with a pair of small tweezers, then tinned them with flux and a soldering iron – this makes any breaks in the traces much easier to see.
Then, I bridged all of the breaks with very fine wire (a single strand of 16AWG stranded cable) – this is a pretty painstaking process, I got some good video from my microscope.
I tested continuity across these traces between both sides of the board following their repair and everything now seemed OK – the image below puts into perspective just how small these traces and their repairs are versus the rest of the mainboard.
I’m fairly experienced at soldering but I don’t really like doing work this fine, though needs must. It looks like I’m shaking a lot but I have pretty steady hands, it’s just all very small! There are a few mistakes that I’ve left in the video because that’s the reality of this kind of work, it’s especially challenging when multiple fine traces have breaks in a tight area that all need repairing, it’s very easy to knock a previous repair. Also, trying to make something “perfect” can undo all your good work quite easily with one small jump or mistake. It took me a couple of hours to repair all of the traces.
Repairing this kind of trace rot is not easy work, unless you’re a professional with all the right equipment who knocks out a lot of these repairs and has a lot of experience with extremely fine soldering. The traces are teeny tiny, and despite having good eyesight this is not something I could do by eye. If in doubt, have a qualified person do it for you.
Some people choose to jump across the entire mainboard with jumper wires, bypassing the problematic traces entirely – this will work just fine and is probably easier to do, but is a bit unsightly and leaves flying wires that could get damaged or pulled off, hence I fixed the traces themselves.
I then reassembled the system for testing following the previous repair work.
Removing the rubber feet to open an Xbox usually takes all their adhesive off, so I used some strong double-sided tape and cut it to size to reattach them.
With the Xbox reassembled, it now seemed to work perfectly! We gave it a good soak test for an hour or so playing Need for Speed: Underground 2 and Halo.
