Monday, August 15, 2016

Understanding related components in a circuit

When you open electronics equipment like the television for the first time, one can easily get intimidated by the number of components in there.


This shouldn’t be the case if you have adequate knowledge in basic electronics especially on basic functions of the components and how to read circuit diagram.

Actually in my case if I have a problem with electronics equipment I never rush to open it first, and especially if there is something on the screen.

First I analyze the symptom systematically till I am very sure which circuit block is causing such a symptom.

Wednesday, August 10, 2016

Understanding and troubleshooting CRT Television Audio circuit

Some times on your line of repair you will encounter a case where a television is brought in for repair with NO audio PICTURE OK symptoms.

Please note that I mean the picture is present and very clear but there is no sound from the speaker. If it is no audio and no picture this is a different case and should be handed on another topic

Below you can see an audio circuit of a television using ic LA4266. Things to look for here include.

Understanding and troubleshooting CRT Television Audio circuit

Some times on your line of repair you will encounter a case where a television is brought in for repair with NO audio PICTURE OK symptoms.

Please note that I mean the picture is present and very clear but there is no sound from the speaker. If it is no audio and no picture this is a different case and should be handed on another topic

Below you can see an audio circuit of a television using ic LA4266. Things to look for here include.

Tuesday, August 2, 2016

Aucma CRT television screen blank but power ON led lighted.


I received an Aucma television assembled here in Kenya in my shop for repair, the screen was blank and therefore I decide to open it for further investigating.

The power ON light was green and therefore I expected the power supply was okay and therefore after opening the set I went straight to the RGB circuit.

Just before I was about to pull my meter to do some voltage testing on this circuit I noticed that the heater light was ON.

Once I saw the heater bulb was ON I kept aside the meter and proceeded to the fly back transformer looking for the screen POT.

Tuesday, July 26, 2016

Radio theory handbook


When I was struggling to find out how I can start in electronics in the year 2000.
I kept searching the web for electronics materials and in one site which I cannot remember I found an info which changed my career in electronics completely.

Monday, July 18, 2016

LG CRT Television mode RT-21FB55VE picture top squashed.

I received this television in my shop with the complain of having the top part of the screen squashed and the part of the picture with dark stripes.

I applied the power to confirm what the customer said and this is what is saw.



Friday, July 8, 2016

Understanding the standby circuit in LED-LCD television

When troubleshooting switch mode power supply (LCD/LED TV) it is very important to check the status of the standby voltage.

If you open the LED/LCD television and disconnect both the main board and the inverter board if they are separate, you will notice that only one outlet will have a voltage and the rest will be zero.

This voltage is usually 5Vdc and is called the standby voltage, if this 5 volts standby is not generated means the SMPS is defective and therefore you should not continue with any other test before you know what is blocking this voltage.

Saturday, July 2, 2016

Chanwong TV-china with No Power symptoms

This TV has no power symptoms-first I checked the fuse and it was blown but not blacked inside meaning there was no heavy short in the supply.

Remember a fuse can tell you a lot about the last moment of any equipment before it died (in medical terms postmortem)

1. Fuse blown, dark inside - Means the machine died due to heavy short. Please be sure to use the light serious Lamp to bring up the machine after replacing the fuse.

  

2. Fuse blown, clear inside- Means the fuse might have died through natural dead (e.g. old age)

Tuesday, June 28, 2016

What kills, amps or volts?

Most newbie in electronics always have question on which really kills, amps or volts? in this video you will get the answer to this question.

Friday, June 24, 2016

LG 15 INCH MODEL 15FG5MB-T2 DEAD NOW REPAIRED

I meet one of my neighbor on my way to work and wanted me to pass by his place to check out on his TV which had a problem.

I passed by over the weekend and since I was not prepared to repair on site I carried no tools with me.
Before taking the TV I did initial test by applying power to see if there is any sign of life, after applying the power and pressed the power on button I noticed the TV was dead as dodo.

Friday, June 17, 2016

Understanding how fly-back transformer works

Fly-back transformer is probably the biggest component in CRT television or CRT monitor.

In this article I am going to highlight few things about his component.

Technically speaking FBT is simply a transformer just like any other transformer and the mode of operation is the same (It has the primary side and the secondary side)

below you can see a diagram of internal structure of a fly-back transformer.

Sunday, June 5, 2016

LG 21” CRT Television intermittent dead symptoms

This TV belong to a friend of my friend, from the word go my friend informed me that his friend suspect the switch is faulty because the TV would stay on so long as the finger is pressed against the Power on button.

So I prepared myself with a limited number of tools because I considered it a small assignment, in any case the problem has been isolated and mine is to confirm the same and do whatever is needed and go back to my house.

On reaching the site the owner give me a little background and the story was the same with the previous one and even pressed the power on button to confirm what she was saying.