Do you get schematics?

[chico1st]

When you guys are fixing TVs, monitors, PSUs etc do you get schematics for them?
Some troubleshooting just seems to be impossible without them.

If you are fixing a TV and don't have the schematics do you just check all the FETs, fuses and caps? since you don't know what any voltage levels should be or do you dissect the design from the PCB?

[999999999]

Re: Do you get schematics?

Yes, get the schematics for the specific product when possible. When not possible, try to get the datasheets for any ICs present.

Yes check discrete components too, consider the symptoms of the device and what could cause those. You do usually have a fair idea of what voltage levels are supposed to be based on what the circuit does and often when there is a fault, voltages don't just change a little bit, they are WAY off or no voltage or in the case of bad capacitors, large ripple present that shouldn't be. The most effective repair person is someone who already has some familiarity with the electronic circuits used to make that type of device work.

Yes otherwise you begin to dissect the design tracing either backwards until you find an unexpected value or forward from power input - again it depends on what the problem is.

It is easier to describe method for a specific situation and hunt for info than to try to vaguely describe a methodology. Sometimes it also helps to research common faults for the specific product model, similar models from same manufacturer, and similar products from other manufacturers. When all else fails you take a modular approach and replace the most likely, entire circuit board OR decide it is not cost or time effective and abandon it... sometimes if you have no expectation that a replacement board will do any better or last any longer, it becomes an issue of whether you want to perpetually repair it.

In other words I consider a repair far more viable if I can improve the circuit or product in some way to make it less likely to fail the same way again. That might include improving chassis ventilation, or higher spec components, adding or improving heatsinking on overheating parts. Other times it isn't important, for example if more than half the desired or reasonable product life is already over, having it last as long after repair as it did before repair is good enough so long as the value of the (working) product exceeds the time and cost to repair it.

[retiredcaps]

Re: Do you get schematics?

When you guys are fixing TVs, monitors, PSUs etc do you get schematics for them?

http://elektrotanya.com/