TV repairs

crasy dash

Hi all I'm a newbie on here just looking for a bit of info please.

I'm an electrician by trade but now working in an electrical shop selling white goods.

Working here about 4 months and I'm just wondering about the amount of TVs that come in for disposal due to just going faulty and not turning on etc surely some must be able to be repaired.

I'm curious and wanting to learn what I'm looking at when I take them apart out the back of the shop when I'm bored haha.

Any knowledge ye are willing to share would be great.

thanks for reading this !!!!

DublinDilbert

crasy dash wrote: »

Hi all I'm a newbie on here just looking for a bit of info please.

I'm an electrician by trade but now working in an electrical shop selling white goods.

Working here about 4 months and I'm just wondering about the amount of TVs that come in for disposal due to just going faulty and not turning on etc surely some must be able to be repaired.

I'm curious and wanting to learn what I'm looking at when I take them apart out the back of the shop when I'm bored haha.

Any knowledge ye are willing to share would be great.

thanks for reading this !!!!

The problems with the majority of lcd tv's are power supply related. Read up on switch mode power supplies. Quite often it's down to bad electrolytic caps, this is usually obvious as the ends bulge out.

crasy dash

DublinDilbert wrote: »

The problems with the majority of lcd tv's are power supply related. Read up on switch mode power supplies. Quite often it's down to bad electrolytic caps, this is usually obvious as the ends bulge out.

Much obliged for the response and the guidance will do that now and let you know if i manage to fix one there is abunch in the store im curious to take apart:pac:

Any precautions i should take from your experience so i dont do anything silly and blow a cap in my face:(

DublinDilbert

The lcd back light inverter will have some energy stored, but that will usually dissipate quite fast once power is removed. You could always connect a 1k resistor between 2 old meter probes to allow you to discharge caps.

The LCD back lights are quite powerfully, so I've seen damaged connectors too from heat/current.

If replacing an electrolytic cap obviously make sure the polarity is correct.

The back light inverters are similar to a hf ballast for a fluorescent light, I think they are called a resonant converter, check the output transistors aren't shorted in this.

The front end to most of these will be a rectifier with pfc control on it. Sometimes there is a little circuit which controls the precharge of the caps.

Also never rule out poor solder or cracks (usually on big components), microscope is great for these. The last crt I fixed on a very expensive cnc milling machine was a solder crack on the fly back Trafo. When I'd touch it with my insulated screw driver the monitor would cone to life.

crasy dash

Great information there dublindilbert i only have a fluke 175 meter i have seen other posters on here referring to esr meter i see these on ali express etc would i benefit from buying one?

As i said im more curious more than anything else im not going repairing tvs just wish to learn about circuits and component fault finding

I know there is a small 24inch tv in the store that will be my first victim
thanks again for the info will keep you posted as i progress:)

crasy dash

http://www.ebay.co.uk/itm/Transistor-Detector-Tester-Diode-Triode-Capacitance-ESR-Meter-MOS-PNP-NPN-UK-/391184294360?hash=item5b1466a1d8Just looking at this meter what do you think is it worth a punt?

Keplar240B

Last and only CRT tv I looked at it was a fuse on the PCB that was blown.