I had this Toshiba Satellite Pro P6100 laptop sitting around. It had been tested some time ago, and it had errors in the video graphics memory. I had used VMT which is a Video Memory Stress Tool, to run diagnostics on the video graphics memory .
This is what the screen looks like. What we see at the top of the screen with the greenish lines are artifacts on the display due to these memory errors. Now the memory errors are not stable, they appear at different addresses and affect different bits, so it could be a graphics processor problem or a memory problem. This laptop had a separate card which contains the graphics processor and its two memory chips but also interfaces to the keyboard, mouse pointer buttons and the system board. Due to my previous success with using my SMD Rework station to reflow a laptop system board, I thought I should try this again.
I removed the graphics add-on board, and taped up the areas that I did not want to heat up. I also attached a thermocouple temperature probe, just like I had done previously.
I worked my way around the board, heating the three chips gradually, and then concentrated first on the graphics processor, and then afterwards on the two memory chips. After letting it cool down, I then reassembled the laptop and was rewarded by a clean display with no signs of artifacts.
Another successful “Reflow.IT“. I suspected that due to the nature of the problem where the memory errors occurred at different addresses and different bits that it was an intermittent connection problem with the chips. The reflow helps to melt the solder and let it solidify “hopefully” making good contact on all the chip connection points. It looks like it worked. Now what do I do with a laptop with a Pentium 4 and 512MB of ram. It runs Windows XP and has a 40GB disk drive and has a serial port on it, which is quite sadly lacking from most modern day laptops.
Speaking about faulty capacitors reminded me of a Toshiba laptop that I repaired in August 2013. This Toshiba laptop belonged to a friend’s landlord – if my friend could get it fixed economically, he could score brownie points – always an advantage to be on good terms with your landlord, especially when the rental climate looks like rents are rising.
This is with the laptop taken apart – see the massive amounts of dust in the cpu heatsink heat distributor and fan just above. The laptop would fail to boot and from research on the internet, the cause was a failed capacitor – the rectangular NEC TOKIN inside that metal plate near the bottom left. This capacitor was a bugger to remove – I tried Infrared heating – it just started to cook the plastic top and did not budge. These are often glued down, but because it had a large contact area on the board, it was impossible to remove without more specialized equipment that I don’t have, i.e. dark infrared reworking station with under board heater and good temperature controller.
I had to effective destroy the capacitor piece by piece, layer by layer. Actually capacitors are fragile and easy to destroy especially if I am wielding a scalpel. Eventually it was removed, and I replaced it with four smd capacitors. I had to use a fibreglass pen to remove the green coating from the board in order to do the soldering of the replacement capacitors.
Now a closeup of the board with the replacement capacitors. The motherboard was reassembled in the laptop, after cleaning all the dust, of course – then powered on, and it worked. Total cost to the friend’s landlord was $60 plus a lot of brownie points.
[Note] I have since learned that I could have used my existing infrared rework station by using the under board heater, then heating the capacitor with the infrared, and use my hot-air rework station to add additional heat – to keep the temperature steady. But that comes with a risk of damage to the board due to the heat being there for much longer – my scalpel was much better.