How to check television power supply? What are the preacutions on checking it?

[akosipanda]

I'm about to teach tv repairing next year... I want to learn more on it since I really didn't pay too much attention to my professor when i was in college. I want to start knowing how to check power supply of tv and other sections. What are the safety precautions to consider when checking it using multitester... Pls help me...

 

[tvtech]

Here we go....are you talking about CRT or LCD or Plasma TV's.......????

Welcome BTW. Your first post. Maybe Nigel Goodwin could be of assistance once you have clarified your particular " field".

Highly suspicious. Since TV repair guys have never been taught by professors......hey, go to Varsity and then try and teach people to fix TV's.......what a waste.

Hugh??

 

[akosipanda]

for CRT tv... pls help...

 

[Nigel Goodwin]

Sorry, but my view on this is that you shouldn't (under any circumstances) be teaching others how to repair TV's if you know nothing about them yourself.

 

[tvtech]

Sorry, but my view on this is that you shouldn't (under any circumstances) be teaching others how to repair TV's if you know nothing about them yourself.

Agreed. Tis true.

Us TV Tech's know how not to kill ourselves when a Chassis turns on you....

 

[akosipanda]

I have learned a few about tv... most of these are basics... I still have 1 year to prepare that's why I'm here asking for help...

 

[cr0sh]

One hand in pocket is a good rule to start out with.

 

[tvtech]

One hand in pocket is a good rule to start out with.

LOL...That is good advice

 

[JimB]

I'm about to teach tv repairing next year...

I really didn't pay too much attention to my professor when i was in college.

What are the safety precautions to consider when checking it using multitester...

Pls help me...

A fine example of the blind leading the blind.

This can only end in tears!

JimB

 

[akosipanda]

why do some people here are so judgmental... If you can't help me then that's fine! Thank you for your time!

 

[cr0sh]

why do some people here are so judgmental... If you can't help me then that's fine! Thank you for your time!

Well, the thing is, CRT-based televisions are not something you want to play with unless you know and understand exactly what you are doing. You can easily -kill- yourself (or instruct your students wrong, and then they -kill- themselves). I am always wary when I have the back off a monitor (and really, any powered circuit - even low voltage ones!). So be careful. However, I doubt that you will be able to teach yourself everything you need to know about television repair inside of a year, to the point where you would have any business teaching others. I am really surprised that they (the school) would allow someone to teach something they aren't qualified to teach (then again, there's the US public school system - but I digress)...

 

[tvtech]

Well, the thing is, CRT-based televisions are not something you want to play with unless you know and understand exactly what you are doing. You can easily -kill- yourself (or instruct your students wrong, and then they -kill- themselves). I am always wary when I have the back off a monitor (and really, any powered circuit - even low voltage ones!). So be careful. However, I doubt that you will be able to teach yourself everything you need to know about television repair inside of a year, to the point where you would have any business teaching others. I am really surprised that they (the school) would allow someone to teach something they aren't qualified to teach (then again, there's the US public school system - but I digress)...

Well said.

 

[rfs100]

why do some people here are so judgmental... If you can't help me then that's fine! Thank you for your time!

With something this damgerous, people are NOT being judgemental, they are attempting, in a light-hearted way to tell you that this is dangerous. If you dont know the dangers of high voltage, high amperage power, which is pretty much page one in any electronics book, what the hell will you do once you have found all of your voltages?????

 

[rmn_tech]

R.I.P.
Here lies the body of Arnold Dwyer
The late lamented D.I.Y'er
In the back of a telly a
repair he affected
But the flash and the bang
were most unexpected
Screwdriver in hand he gave
it a prod
Now he lies here under the sod
The moral is plain and easy to see
That job he was doing, was
best left to me
To save a few bob, he caused
trouble and strife
Receiving a bill that he paid
with his life.
So don’t do it his way
It's not clever or sharp
Unless you're quite partial
To playing the harp

 

[guys007]

For checking tv smps u must take some care...If the power supply is dead condition, the main filter capacitor stores 300V dc....first you should do discharge this capacitor by connecting a 60watt bulb. If smps is working it automatically discharged....steps for finding faults
1. check 300v dc arrived at collector/drain of switching element.
2. Check starting supply of smps.
3. Check all diodes & resistors, ICs for any defects.
4. Most of the faults are blown the switching element.
5. Check feed back/error supply.


Caution: do not touch live area

 

[KeepItSimpleStupid]

Here is an early lesson. I was maybe 12 YO when I started working on TV's. Isolated chassis with tubes. Now, you MUST have an isolation transformer. Without it, you'll see sparks fly easily.

 

[Nigel Goodwin]

Here is an early lesson. I was maybe 12 YO when I started working on TV's. Isolated chassis with tubes. Now, you MUST have an isolation transformer. Without it, you'll see sparks fly easily.

Youngsters today!

No isolation transformers back in the valve days

The early valve sets even had the chassis connected directly to one side of the mains lead, with a two pin plug the entire chassis could be (and often was - 50% chance) live full 240V mains.

 

[ben7]

Here is an early lesson. I was maybe 12 YO when I started working on TV's. Isolated chassis with tubes. Now, you MUST have an isolation transformer. Without it, you'll see sparks fly easily.

LOL when I was a few years old I was playing with some tools and I stuck a screwdriver in an electrical outlet with no cover...big bang, weirdest part is that I didn't cry I still have a scar on my thumb though! That is why you should always watch children closely.

From then on I've been an electrical enthusiast

 

[KeepItSimpleStupid]

Me too with the electrical outlet. I wouldn't play with things that were supposed to have a cord and didn't. My father had to tie a string to an toy iron for me to play with it. Last year I repainted a room and replaced all the outlets with the new "tamper proof style".

You don't go back far enough until you have seen an old TV with channel 1. I have two of them in the basement. One is an RCA and the other a Philco. I THINK the RCA is a CTC30. The no transformer series filament tube sets were later.

In high school when my 3 KV HV power supply that I built went south, I used a TV to get the HV I needed for my "Electroculture and Radish Growth" experiment. That was tame compared to a 100 KV 0.1 A x-ray supply and a 15 kV 1.5 A electron beam shunt regulated supply and the 3 kV supply for a 1000 W RF transmitter that I had the pleasure of maintaining.