POST & BIOS Question : Laptop problem

RegWorts

I`ve been given a Fujitsu Amilo L6825 laptop which is faulty.( It fails to get by the POST test so doesn`t even reach the BIOS option.(It switches ON, fans run but black screen with no BIOS beeps. The only light lit is the ON light )

Using substitution and known working spares, (I have the same model of laptop) I have deduced that the original problem was possibly due to a faulty harddrive .(does not work in my laptop)

However, even with a known working harddrive, it still does not boot up (no display , no beeps)

I`ve gone through the usual method of faulting by disconnecting the CD Drive , HDD , memory : stick removal + slot swops ,battery removal , screen swop , power unit swop etc. and still no joy...plus a visual check of the circuit board for damage or overheating or blown capacitors etc ) plus a "Default Reset" by pressing ON button for 30 seconds
To me , this now looks as though the problem might be on the motherboard.

As it does not seem to go through the initial POST or BIOS checks I wondered whether it might be the BIOS. Fortunately it is a removable chip so I swopped it...Still fails as before.

The only other option available to me now was to try and swop the CPU................Swopped and Still fails

(note both CPU and BIOS chip still work OK as fitted back OK into my own laptop )

Anyone any idea what to do next?

I assumed that the BIOS chip controlled the POST test...but does it?

If not what does?

Any suggestions most welcome

Reg

(I`m a retired maintenance engineer with plenty of free time and desire to find a solution to this problem so don`t really want to just change the motherboard ...providing I can still get one ! )

23n1th

You've swapped everything in and out to the laptop apart from the motherboard, if as you say everything works on the other laptop then it has to be the motherboard. Motherboards aren't really fixable. Probably not what you want to hear.