Baking A PCB

[ParkingLotLust]

Ive got an Xbox thats being a bit silly, and Id like to see whether its a cold joint somewhere or not. Instead of going over every single point with an iron, would it be feasible to bake it at a low temperature, just hot enough to reflow the solder on the board, or would parts start to move and melt?

 

[whiz115]

how? do you have the right equipment to do that?

P.S

something like that could help... but it's risky, it's mostly for disoldering
and it's easy to damage the PCB and some components.

**broken link removed**

 

[ParkingLotLust]

Yeah, I was thinking of using a heatgun to reflow the solder around the RAM chips, but I dont think thats where the problem is. However, I dont know exactly where it is, or I would have fixed it by now. Figured the oven would be the easiest, as it would heat up the entire board at the same temperature.

 

[Sceadwian]

Xboxes are notorious for their hardware failures. If it's under warranty return it to get it fixed. If it's not, do whatever you want, just don't be surprised if it completly stops working afterwards. Cold solder joints are typically associated with hand solder jobs not wave soldering or the typical reflow methods that would be used in a modern board like an Xbox, so you're probably not going to get anywhere.

 

[whiz115]

Figured the oven would be the easiest, as it would heat up the entire board at the same temperature.

yeah...but not all components can handle the temperature needed for
the solder to reflow....

 

[ParkingLotLust]

Its a v1.0, so its way past warrenty. I bought it broken, just for something to play around with. However, the scene has died down a lot due to the release of the 360, so getting the diagrams I need is a lot harder now than it was a year or two ago.

 

[Sceadwian]

So it's junk anyways. Try it in an electric oven, preheat the oven on normal heat to say 125C (250F) Once it's pre-heated turn it to broil as long as you think it would take the board to reach 375F (that's the tricky bit) Maybe a sheet of tin foil over the top of the board to help disperse the IR coming off the coils of the broiling coil to the whole board otherwise it's going to spot heat pretty bad. Even heating is going to be a problem in a conventional oven. Turn the heat off, open the oven up and let it convection cool. I'd guess there's about a 90% chance your burn at least part of the board, or a component that can't handle the heat.

Do a google image search for reflow oven. You'll find a lot of images that look mysteriously like the conveyor style pizza ovens you see in many stores. They're just highly temperature controlled and have convection cells inside for pre-heating and cooling, much like their pizza brethren =) About the biggest addition you can make to a toaster oven or conventional electric oven is a convection fan.

 

[ParkingLotLust]

We have a convection oven One of those new propane ones with an electric oven that you can set to normal, broil, convection, etc.

 

[Nigel Goodwin]

Cold solder joints are typically associated with hand solder jobs not wave soldering or the typical reflow methods that would be used in a modern board like an Xbox, so you're probably not going to get anywhere.

Just the opposite, dry joints (called cold joints the other side of the pond) are commonplace in wave soldered equipment. With modern surface mount methods, a VERY common repair method is to reflow the board - but using a hot air system, NOT putting the entire board in an oven!.

 

[ericgibbs]

You can use a commercial aerosol 'freezer spray' , careful use, using the tubed nozzle supplied with
the aerosol can quickly 'provoke' a dry joint into fault condition.

The main advantage is that freezer can be used while the pcb is operating and can applied to a small area of the pcb, that is suspect

Remember to clean off any residue from the pcb, I usually give the pcb a careful, quick blow over with a hair dryer.

 

[ParkingLotLust]

That's just the problem. I *thought* the problem was around the LPC port and its traces, however, they all check out. Ive put in a chip with a recovery mode, and after many tries, it *will* boot, but the screen is garbled and very colourful. After even more attempts I finally got a screen that was semi-readable, but all the colours were off. This leads me to believe the problem is somewhere around the video encoder. Would applying flux to the area around the chip, and to its pins, and heating it with a heat gun until I can see the solder "wetting" work?

 

[Nigel Goodwin]

That's just the problem. I *thought* the problem was around the LPC port and its traces, however, they all check out. Ive put in a chip with a recovery mode, and after many tries, it *will* boot, but the screen is garbled and very colourful. After even more attempts I finally got a screen that was semi-readable, but all the colours were off. This leads me to believe the problem is somewhere around the video encoder. Would applying flux to the area around the chip, and to its pins, and heating it with a heat gun until I can see the solder "wetting" work?

It's worth a try, but you probably really need a more concentrated heat source.

 

[ParkingLotLust]

**broken link removed** shows how to reflow the solder around the RAM chips, if its giving a slightly different error, and it looks like using a heatgun works. Ill pick up a heatgun within a few days and give that a shot around the video encoder. Hopefully that does it.

 

[ParkingLotLust]

Tried redo-ing all the RAM chips, video encoder, PIC, TSOP, and MCPX, but it still does the same thing. Since Ive really got nothing to lose, I guess Ill pop all the plastic pieces off that I can, and bake the board. Any tips as to temperature, time, etc? There are quite a few electrolytic caps on the board, what would be the best option besides removing them, so they dont pop?

 

[whiz115]

https://www.youtube.com/watch?v=T5nfmJTQJr8
https://www.youtube.com/watch?v=hjjinHmEoss&mode=related&search

i hope it helps.. your idea to bake all the board is not right...

 

[Sceadwian]

I stand corrected.

 

[ParkingLotLust]

Thanks for the links, but thats for a 360 with the 3-red-rings error. Im talking about an original Xbox that's Flashing Red and Green (ie. FRAG / Christmas Lights)

 

[whiz115]

i'm giving you a clue of what else you could try instead of putting the poor board inside an oven...

 

[nikolausc]

I've had to do this before (v1.1) , I did it for 15 mins when the oven was preheated to 150C

It was very hot when it came out and some plastic things were kind of melted, but it worked fine so I didn't complain

 

[kasamiko]

Don't forget the "sauce" hehehe...i like it hot...