Hey - I've got an xbox on which the MCPX chip has decided to become a little loose from the board (causing the xbox to not boot). After trouble shooting the sucker, and finding out what the problem was, the only solution that would make the box work was putting quite a bit of pressure on the chipset from my thumb, my guess is that the solder attaching it to the board was faulty or something along those lines, now I've been told a couple of suggestions: 1) Heat Gun the chip to redo the solder 2) Bake the mother board at 230 F 3) Blow Dryer 4) Give up haha, well obviously #4 isn't my goal yet, I'd like to know exactly what I'd need to do to bake it, is it as simple as plopping the mobo in or should i remove the heatsinks and do it or what?
If you look at most componentry things start getting a little frazzled above 70 degrees celcius. I don't know the conversion rate but baking it in the oven sounds like it would be FAR too hot for all the tiny IC's and stuff all over the board. I reckon your best bet is with a very fine soldering iron.
I can tell you from experince, DON'T BAKE PCBs!!! I tried that once for a circuit board (for my car CD player) and it said 240 degrees (F), and it fried it nice and crispy...granded the chip that broke off was back on, correctly, but it fried EVERYThing else.
Um yeah, don't put a PCB in an oven...that's recipe for burnination... Just rewet the solder joints with a soldering iron.
If you google SMD baking, you will find that there is a specific time-vs-temperature curve used to activate the solder paste. This is when everything is properly setup (solder paste applied correctly, which it sounds like it wasnt). In manufacturing, they do the surfacemount stuff first, then solder the other components afterwards. You dont want to rework the mobo by baking it. Not all the parts on a finished board can handle it. The proper way to fix this would be to use a rework station that uses hot air and a special tip shaped like the IC in question. These are expensive. Your best bet is to reheat just those legs that are loose with a finetip solder iron.
Try to get conductive epoxy. Some types are made for SMD chip mounting. Even the cheaper types made for RF shielding are good enough if the broken connection is just a data line carrying a few mA. Make sure the surfaces are blank. Epoxy does not have anything like flux in it.
lol the problem isn't that it's like a chip with legs on the sides, those are easy, I've modded xbox's and what not for awhile now, and have no problem for doing that, the chip I need has no exposed metal which is the problem, I need to melt something beneath it that I cannot see, a pic of the MCPX is here: That's why the only real way I can figure on how to fix it is to heat the entire board up enough to melt the solder, then let the chip's own weight push it down, as my pushing on it would cause all the solder to squish out and bridge things that I can't see. If the board gets fried, no biggie, I can get another fairly easy, I'd just like to try to save this one first (haven't had a single xbox die on me yet - one i've bought broken or working)
I think I rember seeing somewhere else on these boards, that there is some sort of heat sheielding tape available?? if somone could point in the right direction.... Anyway, I would shied off a large surrounding area with heat shielding, and leave only the small area of the chip exposed, then hit it with a heat gun
It seems like those BGA chips weren't designed with modding in mind. Perhaps you could try using some strong tape or glue to fix it down to avoid the hassle of soldering/heating it? How much pressure needs to be applied to it?
It's quite a bit, I considered drilling 2 holes on either side and attaching like a heatsink (passive) and screw it down tight enough to compensate and put pressure on the chip and cool at the same time (the chip gets rather hot at times) I don't think glue would work well simply because i need pressure right on the top of it, rather than the sides, I think it kinda bubbled up (sides are down, middle is up) I think I may try to get some of this tape stuff - i've got some local resources that may have it, and try the heat gun, so far that seems like the best idea if the oven is a bit too much for other components Also the board was only like $10 or so, I bought the mobo, hdd caddy, dvd caddy, and the full case for $20 from a shop - so if it's trashed no biggie I'll buy another
Are you 100% sure that its the MCP chip thats loose. Sure its not a grounding issue or something else. Those types of chips are pretty resiliant and ive NEVER seen one come loose from a board, and ive seen ALLOT of dead motherboards.
Yepo, if you push down on the MCPX chip then it boots fine, if you leave it alone it errors and says no hdd found (the actual error means no hard drive connected) which makes no sense, don't know where there would be a grounding issue, you have any ideas? - and ya, i've seen my share of mobo's never seen this it's weird, but i've tried screwing the entire board to case, no luck etc, there's no top shielding in the xbox, but that shouldnt be a problem
I started playing with the mobo, and if I pushed on the MCPX chip alot (bending the board a bit) it would boot up no problems. Well I thought this was because of a bad chip, but no! There are 2 small metal tabs on the shielding (near the MCPX chip) they are not screw ones, just metal tabs - one of which was slightly bent down. figuring what the hell I bent it up, threw the mobo in and it works perfectly now. If you all need pictures let me know. This was a 1.3/4 system with a tsop flash and an error code 8 so thanks Holst - with your help I narrowed it to the grounding issue !
let me tel you how it is done When a board is manufactured, all the surface mount devices are placed on the board then run through something akin to a pizza oven to solder the parts on. Thu-hole stuff is placed in the board in a later operation. Baking the board in thoery would work, but you risk damaging or stressing other components on the board. Here in the prefessional world, we use hot air to heat the connections. If you have a heat gun, you may want to try blowing hot air across the connections. What you may find that the pads were not properly coated in solder paste and this will not fix things. Then you are looking at removing the chip and re-soldering it. You'd still use the heat gun to heat the solder. Attach a suction cup to the top of the chip to pull it free. This keeps you from burning your fingers. obviously if you are going to do some SMD soldering without the right equipment, keep your expectations low. good luck
just put the board perfectly level and heat up the chip with a heatgun till it settles. Just make shure its level. As for the heat those chips are designed for extremly high heats so its fine with solder melting temp. Other chips around it may be sensitive so try to sheild them. Thats as far as I think it can go.
