On 07/10/2019 22:25, Tim+ wrote:
AlexK wrote:


"Tim+" wrote in message
...
My wifes MacBook Pro power supply went phut yesterday. If had a look
inside and a reasonably sized resistor has burnt out (about 4mm in
diameter).

Is there any point in just replacing the resistor

Nope, those dont usually die by themselves.

or has something else almost certainly blown as well

Yes, almost certainly.

(even if invisibly)?

Very likely.

If so, what would be the next most likely candidate? Bridge rectifier?

That wouldnt normally see a power resistor fried because
the rectifier usually fails open circuit.

Bull****.

Most failures on PN junction start as a loss of bakwards resistance due
to reverse breakdown - especailly under voltage spike cinditions. Only
if there is no fuse does what is now just a silicon resistor go open
circuit. With the magic smoke coming out
]


More likely the main
ic controller that has failed in a way that has the switching
transistor on all the time instead of being switched.

Okay. I guess Ill ditch plans to try and mend it. Ill keep the magnetic
power lead though as its in good nick and weve had one of these fail in
the past.

Tim




--
€œThere are two ways to be fooled. One is to believe what isnt true; the
other is to refuse to believe what is true.€�

€”Soren Kierkegaard