tv trouble shooting part three(neon tester)

high voltage power supply is another power source with secondary voltages that runs tv just after start up.so lets say your on a service call with out a print tv has sound no picture.this is several reasons one no high voltage two no video or crt now were are talking about analog tv.one tool i use is a neon test tool used for checking wall out lets. if you hold it near flyback or anode lead and hv is present neon bulb will light from magnatic field in the flyback.just hold it in your hand make no connection what so ever to the tv its a cheap tool and quick dianosis.if no hv no blub light then start troubling shooting starting with low voltage power supply.check the b-plus on horizontal drive transistor collector and if no hv check b-plus on horizontal output collector.remember visiual inspection of componets,dark spots on ciucuit board top and bottom look fo leaking caps.check low ohm resistors remember their same as fuses.sand bock resistors trouble shoot just like low voltage power supplies.and of course look for fuses some mfg seperate both power supplies with a simple glass fuse.you can seperate in trouble shooting to fine shorts between two sources by removing either a fuse or b-plus supply resistor will not hurt the tv to shut down one or the other sources.then you can tell wether a short is in low voltage supply or hv supply.the point is that you do not always need a print if you done this work for years like my self 28 years worth you remember the basic circuits. a good service tech should be able to compele 12 to 15 services calls a day and be quick about it 20- 25 min per call.my next editioral will be on vertical trouble shooting the quick way.

Post edited by: hobbist, at: 2008/06/05 18:35