About Repair History
For the past one week ago i had been supporting one of my buyer on electronic repair. He told me that he was fixing an amplifier and do not understand why the power transistors and some resistors were getting hot even though he had checked all the components in it. I was puzzle too because usually one would easily locate the bad parts if one have check on all the components in the amplifier. This morning i got an email from him telling me that he have solved the problem and this is what he wrote
Thanks Jestine,I have solved the problem,this amplifier was sent by the customer to his repair friend before he send it to me for repair.When I observed carefully I found that the power transistor should be arranged as PNP-NPN-NPN-PNP and not NPN-PNP-NPN-PNP as what I received from the customer ,his repair friend wrongly put in the transistors….that make me headache.Now the amp back to normal. Thanks
The moral of the story here is that one has to check the background of the set that you are repairing because it could have been repaired by someone before. The repair tech could be inexperience, wrongly replace the components or purposely doing this so that if he can’t repair the set, he also do not want other people to successfully repair it.