Back in 2008 legislation called ROHS was made law in the UK. This among other things prohibited lead to be used in solder for certain electrical items such as computers.
Apple computers use a Ball grid array (BGA) of small solder balls to connect their chips to the graphics or logic board (rather than using a socket – in order to keep size in check). In these first revisions of machine which had to have lead free solder the combination of the solder and the Nvidia graphics chip did not work well. The Nvidia chips run very hot (even upto 90 degrees under load) and the constant heating / cooling along with the solder mix resulted in dry joints forming. These dry joints result in the problems that occur with these machines.
Apple acknowledged these faults in time with an extended warranty scheme in which they would replace the logic board / graphics card of any affected machine but no full recall was made.
The unfortunate side effect of the replacement route was that the problem was not eliminated, bad boards were replaced only to fail again some time later.
We’ve seen a vast number of symptoms as a result of this faulty solder, as the GPU chip can cause a whole range of problems – some of which exhibit no graphical artefacts. Here are the most common, but we are discovering more every day.
Distorted video – which duplicates on an external display
Machine powers on briefly then turns off
Machine boots but with blank screen
Machine intermittently powers off
Some of these faults can be from other components but as this issue is so prevalent the suspicion will always fall on the graphics card. Our general rule of thumb is – if there is a machine with an NVida 8600/8800 graphics card in it with faults that cannot be pinned down then reflowing the card is quite likely to bring them back to life.
Costs are £85 + Vat (plus return shipping)
In the unlikely event of the reflow being outright unsuccessful, we will refund you half the cost of the work (this refund excludes any delivery/collection charges).
If the fault recurs within 3 months of work being completed, we will offer you a choice of a further free reflow, or the same 50% refund.
If it fails outside of 3 months we offer a further reflow attempt at half price, but with no further warranty.
There are all sorts of DIY solutions that we hear about here at MacUpgrades, from putting the motherboard into your domestic oven, to using a paint stripper on the board. Rest assured that our procedure is NOT like this! – these diy solutions won’t work for long and will most likely cause more harm than good. As such here is a brief outline of our procedure. Reflowing is as much an art as a science and the temperature ranges and durations have taken us a great number of hours to work out to give you the best result – we will not be revealing those numbers (sorry).
Once a machine has been identified as a likely reflow candidate the machine is stripped down to the logic board level. For a Macbook pro the heat sink is removed and cleaned. The GPU, CPU and north bridge are cleaned to remove all traces of old thermal paste.The boards are then inspected for any signs of physical damage such as burn or liquid damage. For an iMac the logic board is removed and the graphics card removed and cleaned.
The logic board or Graphics card is then prepared for the reflow process. The area around the graphics chips is protected with an aluminium shield to protect the more delicate components from the strong heat that will be used. Thermal probes are then attached to the board with the sensors touching the logic board right next to the GPU.
The prepared boards are then attached to the pre heating plate. This Infra Red heating plate is used to heat the board up to an intermediate temperature to prevent the board cracking under the heat load on the GPU. Once the board is up to temperature (taken from an average of the 3 thermal probes) the reflowing can begin.
A hot air rework station is used, with the correct size and type of nozzle (to allow equal distribution of heat). The machine is set with a high speed air flow rate and has to be positioned evenly and not too close to the chip. We will then use the thermal profile we have worked out to gently increase the average overall temperature of the board to the level where the solder underneath the chip will melt. Once this temperature has been achieved then we maintain it for a short period of time.
That is the reflow element complete. Next the SMC station is turned off and the board allowed to return to the resting plate temperature. This is then reduced slowly to return the board to room temperature where it is allowed to rest for an hour or so.
The machine is then cleaned again and re-assembled. We use arctic silver thermal paste to replace the standard paste used and we use only the correct amount – rather than the slathering that Apple seemed to use.
The machine is then tested with full load on the GPU for 24 hours straight at 100%. This will then cure the thermal paste.
As discussed above the reflow process is not likely to result in a permanent fix. In order to give you the customer an idea of the success rate and longevity here are the statistics.
In the last 2 years we have re-flowed over 200 machines, about 140 MacBook Pro’s and 60 iMac 24″ iMacs.
Of those 8 did not respond to the reflow process. In these cases a 50% refund of the fee was given and the machines returned. This gives an initial success rate of 96%
Of the successful machines 16 required a second reflow during the warranty period.
The average lifespan of the reflow is aprox 6-9 months although there are extremes at each end. It comes down to how damaged the solder / GPU chip as to how long it will last.
If you machine is reflowed and falls outside of the warranty period we will reflow the machine for you again for half price.
The way we describe the reflow process when selling the service is to think of it as renting more time with your machine whilst you make more long term arrangements.
There are technically two other ways to resolve the problem other than reflowing.
Replace the logic board. This is expensive (about £300 ish) if you could find a new unused board it might be worth it – however every board that was made is susceptible to this fault and it is highly likely to happen again. Buying a second hand board should not be done under any circumstances as you cannot be sure what has happened to the the board in its life – as mentioned before some people cook these in ovens!
Replace the graphics chip along with lead solder BGA. This can be a legitimate way of resolving the problem, however the machinery involved to do this properly is hugely expensive and it would cost more than the machine is worth to do it. You have to be sure of the quality of the parts and the procedure that is being done. As these machines are getting older now we would be unable to make back our investment into one of these systems.
Hope this has given you some insight into the problem, and if you would like us to reflow your machine. As always you can contact us on 01223 833412 or use the contact form.