Fortsätt till huvudinnehåll

Why laptop computers keep on failing - the Ball Grid Array problem

The BGA is a popular method of attaching integrated circuit packages to printed circuit boards. The IC package has one face covered (or partly covered) with balls of solder in a grid pattern.

The printed circuit board has copper pads in a pattern that matches the solder balls. The assembly is then heated, either in a heater, or special oven, melting the solder balls and forming conductive connections.

Because of surface tension, the molten solder holds the package in alignment with the circuit board, at the right distance, while the solder cools and solidifies.

Whilst there are advantages, there are also snags. The main ones are that the solder balls cannot bend, for example if the components expand due to warming, or flex due to movement, for example, in a laptop computer which is moved around. The joints are therefore liable to break, and the problem is compounded due to the recent adoption of lead-free solder, which is more brittle. The system is also makes for difficulties in inspection, fault-tracing and repair.

These factors seem to be behind the crop of failures that have affected many makes of laptop computer.

Matters should improve with better lead free solders and the shrinking size of components, but if you have a laptop computer of between 2004 and 2006 vintage, don't be surprised if it proves troublesome.
Etiketter:

Kommentarer

Skicka en kommentar

Populära inlägg i den här bloggen

The Zombie Train that refuses to die

The Guardian has published a couple more articles against HS2, one by specialist rail commentator Christian Wolmar, and another today by journalist Simon Jenkins. The main arguments in favour will doubtless be wheeled out by the commentators: the need for capacity and the disruption caused by upgrading existing routes. HST itself will severely disrupt services to Euston during the construction period. Capacity can be increased at a fraction of the cost by a variety of measures, provided that it is accepted that the additional traffic will run at existing speeds. It is not generally known that the Midland main line is, or was, four track all the way from London to Trent Junction, between Nottingham and Derby. This is because the additional tracks are separate, having been added for coal trains which trundled down to Brent sidings, on the edge of London, from a collection point at Toton in Nottinghamshire, where the Midland Railway build a huge marshalling yard. Beyond Derby, the main l...
Skicka en kommentar
Läs mer

Importing people to sustain demand

I got involved in a discussion with a Youtuber called “Philosophy all along”. This was in connection with criticism of Trump’s policy of deporting illegal migrants, which he argued would be bad for the economy as it would reduce demand. This implies that there is a need to import people to sustain demand. There is no obvious reason why a population should not be able to consume everything that the same population produces. If it can not, then something else is going on. It is a basic principle that wages are the least that workers will accept to do a job. Wages are a share of the value added by workers through their wages. The remainder is distributed as economic rent, after government has taken its cut in taxes. Monopoly profit is a temporary surplus that after a delay gets absorbed into economic rent. Land values in Silicon Valley are an example of this; it's like a gold rush. The miners get little out of it. Rent and tax syphon purchasing power away from those who produce the g...
Skicka en kommentar
Läs mer

Beyond electrification

In an earlier post I suggested a core list of lines which ought to be in an electrification programme spread over twenty years of so. This leaves a residue of routes which it is unlikely will ever be electrified. This include for example All lines beyond Glasgow, Stirling and Aberdeen All lines west of Exeter and Swansea All lines west of Chester Shrewsbury - Chester Everything not listed in my previous blog - electrification plans only scratch surface   Some of these routes carry main line services to London and other cities on parts of the network that are already electrified or included in electrification plans. Others are self contained and others carry light traffic - less than a dozen trains a day. The current plan is that main line services will be operated with the hybrid trains on order from Hitachi, but this is a costly, wasteful and ineffective solution. The performance of the trains will be inferior to the present Inter-City 125 trains on non-electrified lines and the ...
Skicka en kommentar
Läs mer