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Ralph Mowery Ralph Mowery is offline
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Default SMPS troubleshooting

In article ,
says...

Now, consider the analogy of a spun crankshaft bearing on a V6 engine. Only one bearing actually spun - but does a good tech replace only that bearing? Not hardly. You had a spectacular failure (spun bearing) of a small part - but are entirely unaware of the relative condition of the parts immediately adjacent to it. And no

visible means to become aware.

Which is why, for an additional $4, it would pay to replace all the "bearings" as you have already torn down the engine in any case.



At work we had a motor speed controler to go bad. This was on about a
200 HP motor. Called in the factory repair man and he located 2 bad
diodes in the 3 phase circuit. I asked him to replace the 3 rd one. He
said it checked good and they were about $ 200 each. While it may or
may not have been bad, he at my request replaced it. I told him it was
costing us over $ 1000 an hour to hae the equipemtn down,so in the time
it took him to get there and many ohter things, it was maybe a 50 to 100
thousand of lost time if not more. I felt that $ 200 was good insurance.
While the diode was probably good, I felt that if 2 were bad, it may
have weakened the 3 rd one.

Same as when I had a timing belt changed on schedule on my Toyota. The
mechanic recommended replacing the water pump as it was in the same area
of the tare down. Said no more labor,just the cost of the pump and he
doubted it would last another 70,000.