IBM T* Series and A* Series Board issues

[mehtabbukhari]

I have come accross several A22m, A20m, A21m, T20, T21 laptops, which gives a common power-n problem. There are so many defective boards floating around because of this know failiure. I hope IBM has rectied this problem. To be more specific about the problems.

* Machine does not switch on. When you try to switch on the machine your HDD light flash and goes off.
* If machine switches on after several tries then there won't be any display.
* Machine shuts down after 10 to 15 mins of continues usage.
* 0175 CRC error occurs due to the above problem.

I have tried working on these issue as I could do lot of R&D on these planner boards. There seems to be a problem with DC-DC section on the planner board which is malfunctioning after continues load/usage. CRC error is generated as a result of sudden [censored].

There are two ICs used for CPU VRM (Voltage regulator module) ie. ADP3421 and ADP3410. I have tried replacing both the chips along with three MOSFETs (IRF 7811). But the problem persist.

Has anybody been able to workaround this problem?

[david04]

Hi,

No real workaround - but it's an intermittent problem on mine. Sometimes the machine will work fine several days, and sometimes it just refuses to switch on for days at a time.

Can't seem to find any pattern to it, unless its somehow related to heat/humidity and there's a crack in a circuit board or wire somewhere.

Any info you come up with would be appreciated! I'm avoiding buying a nw T42 at the moment, as I'm concerned this would suffer from the same problem eventually.

David.