Ram Repair for GBA mounted chips

[andy smethurst]

Hello, I purchased a laptop at an auction with a 2gb ddr2 ram card inserted,but I was getting ram error beeps every time I turned it on.
I tried it in 2 other laptops, and was greeted with the same error beeps.
This is a Hynix 2gb ddr2 module, and noticed that all the chips on the board are grid ball array mounted. I also noticed a sign of rough handling as it had deepscratches on one side where it locks in to the slot.(no track dammage)
I suspect bending and poor handling may have separated one or several of the soldered points on one or more of the IC's.
I have repaired video chips on laptops with GBA conections, using a heat gun and no-clean up flux.
Could the same procedure fix a problem in this situation?
Has anyone out there tried this with failure or success?
I would very much like to hear from anyone who has attempted this.
I think I will try it anyway, as I have nothing to lose,and seeing that this GBA method of soldering components is getting more popular in industry, we people who repair electronics without very expensive equipment will have to find alternative methods of repair, or throw it in the bin and buy new all the time, and look for new hobies and interests,other than electronics.

Thankyou for any Ideas.

[momaka]

Re: Ram Repair for GBA mounted chips

I would say try washing the RAM first as perhaps there could be something conductive stuck under the chips.
... Yes, I said washing . (water, liquid detergent, then dry for a day or two).

If that doesn't work, then try the reflow. Since this is a RAM module, I would suggest reflowing in a oven rather than with a heatgun, unless you have some thermocouples and can monitor the temperature of the chips (it's rather easy to overheat the chips with the heatgun, and that can kill them).

If using the oven, set it to 240C and put the RAM (with flux under the chips) in it. When the oven reaches 240C, wait for about 3 to 5 minutes, then turn it off, and carefully open the door (i.e try not to make the oven vibrate too much). DO NOT take out the RAM until it has cooled down.

[andy smethurst]

Re: Ram Repair for GBA mounted chips

Well I didn't get to try the washing method, as I jumped in and tried the reflow method with a hot air gun, with no positive results.
I would say that you are right about the oven heat supply, as there are many chips, and on both sides at that. Not knowing which individual chip is playing up, makes it almost impossible to decide where to apply the heat in this method. This may not have been the problem in the first place,as Ram dose fail. If surface mount with legs were used it would be easy to decide,as you would have a visual indication,and save time from using these procedures.