on the job teaching methods....

[unclejed613]

somebody tell me if i went too far on this one?????

a coworker had a sony receiver on his bench, it had no display, so he replaced the DSP/CPU board. then he asked me to help him troubleshoot it. he's a bit of a newbie, and has dreams of management (so he really doesn't think he needs to retain any electronics theory...). so i come over, and he says "please don't embarass me by pointing out a blown fuse...." so i sit down and check the -V on the display tube.... nothing.... so i check the +15V feeding the inverter that makes the -V for the display tube, then i have him measure the +15V at the display board connector, nothing again, so i have him backtrack the +15V to the power supply and measure it there, again nothing, so i have him measure the +15V at the bridge rectifier, again nothing. so i have him measure the AC voltage on the bridge..... you guessed it-nothing. so i have him measure the AC coming from the transformer and the AC going into the transformer, finally tracing it back to .... you guessed it.... a blown fuse. and come to find out there's a blown output transistor and little bits of speaker wire strands laying across the amp board.......

[Steerpike]

All too often the general repair philiosophy is to replace parts until it works.
There is little in the way of troubleshooting and problem solving 'skills' around it seems.

It gives one a good feeling to use your talent to trace a fault, rather than the colour-by-numbers method.

I don't do this for a living, so I really don't care how long it takes me to find the problem, but I'd also rather find a blown transistor that I can replace for zero cost out of my 'spares' bin, instead of ordering a unique, costly microprocessor and finding it wasn't faulty after all.