Many laptops based on Intel's Pentium III "Coppermine" CPUs used the Analog Devices ADP3421 power regulator chip as part of the VRM circuit. This chip is known to be unreliable, and causes affected laptops to not power on.
The first sign of a failing ADP3421 IC is general instability. Affected laptops will begin to crash, freeze, or shut off, especially when under load. During this time, removing auxiliary devices such as modular disc drives, hard drives, or external peripherals may improve stability or allow a dead laptop to power on.
Eventually, the chip will fully fail. When this happens, the laptop will fail to power on. Pressing the power button will result in the laptop attempting to start for a second or two (some LEDs may come on), and then shutting off.
Any laptop which uses the ADP3421 regulator IC may be affected by this problem. The ADP3421 was used on many (but not all) laptops which used Intel's Pentium III "Coppermine" processors. Laptops which instead use "Tualatin" Pentium IIIs do not use the ADP3421.
This issue is most commonly known about on IBM ThinkPads, where it is known as the "blink of death". All Coppermine ThinkPads which IBM built in-house use the ADP3421. This includes the A20, A21, A22, T20, T21, T22, X20, X21, X22, and TransNote. Certain Sony VAIO laptops are also affected, along with the Coppermine revision of the HP OmniBook XE3.
Faster CPUs will put the ADP3421 IC under higher load, so laptops with the fastest Pentium IIIs (up to 1.0GHz) may be more commonly affected.
The only way to repair a laptop affected with this problem is to replace the ADP3421 IC. It is a small surface-mounted chip which will require a microscope and hot air station to reliably replace without damaging surrounding components. If replacing the ADP3421 does not solve the problem, it may also be necessary to replace other chips in the VRM. On the ThinkPad T20 Series, replacement of the nearby ADP3410 and Maxim MAX1631 or MAX1632 chips is sometimes required.
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