Dead LG 21inch Ultraslim Tv Repaired
neyod
I want to repair a 42" plasma tv but needed a smd ic (fds4435).I tried searching around but could not find it so i placed an order on aliexpress and it was delivered today.It took 17 days for it to reach me here in Nigeria though i had already urged the owner of the tv to be a little bit patient and he agreed.Now its time to finish the repair.I will update you immediately i finish repairing the plasma tv.
posted from Bloggeroid
I ordered an IC from aliexpress.com
neyod
The display of the tv is as shown above.
Observation
Voltages on blue and red cathode on tube base is 180v except for the green cathode which is low at 27v
Thought initially that the 15k resistor that supplies the green cathode is bad but on testing it I detect it was good
After some minutes of serious troubleshooting I detect that the drive transistor of value F421 is bad.I changed it and the fault clear away.
conclusion
I wanted to change the whole of the tube base before I decide to troubleshoot the fault,this help build the skill of a repair technician.This is the tv working perfectly.
sharp tv with flyback lines on screen repaired
neyod
The latest trend among repair technicians is just to change the power supply completely with another one.This saves time but what I observe is that it tends to make one lazy when it comes to troubleshooting faults.I decide to troubleshoot this power supply and repair it.
It uses D13005 transistor and after checking components on board I could not detect any faulty component.I plugged the dvd and switch it on but it remain dead.Looking closely I start testing resistors at primary side and it was then I detect a bad resistor of 1meg ohms.
This was easily detected on board through the help of my digital multimeter,it will not have been easy with the analogue meter majorly because of the low ohms range.It is advisable to master the use of the digital meter also.I make use of both multimeters very well.
I changed this resistor and the power supply works perfectly.
It uses D13005 transistor and after checking components on board I could not detect any faulty component.I plugged the dvd and switch it on but it remain dead.Looking closely I start testing resistors at primary side and it was then I detect a bad resistor of 1meg ohms.
I changed this resistor and the power supply works perfectly.
Dvd Power Supply Repaired
neyod
I want to explain how I test relay switches.As we know relays are of different types but I will be emphasizing on the one mostly used in voltage stabilizers and this is because some of my repair friends are interested in knowing how to repair voltage stabilizers and one of the first step to repairing it is to know how to test relays.
Relay switch and its symbol is as shown below,
It has five terminals as shown above.You can test using the battery or through multimeters.
Testing using the 9v battery
This is simple,using terminals 1 and 3 connect the battery to the relay.A clicking sound will be heard, the battery can be connected either way.This should be done within a second so as not to damage the coil on the relay switch.
Testing with multimeter
Set your meter at the ohms range and test terminals 1 and 3,there will be deflection of around 200 ohms will terminals 2 and 5 gives 0 ohms reading.
Do you know of any other method of testing relay switch?please do share with us using the comment box.
Relay switch and its symbol is as shown below,
It has five terminals as shown above.You can test using the battery or through multimeters.
Testing using the 9v battery
This is simple,using terminals 1 and 3 connect the battery to the relay.A clicking sound will be heard, the battery can be connected either way.This should be done within a second so as not to damage the coil on the relay switch.
Testing with multimeter
Set your meter at the ohms range and test terminals 1 and 3,there will be deflection of around 200 ohms will terminals 2 and 5 gives 0 ohms reading.
Do you know of any other method of testing relay switch?please do share with us using the comment box.
The best way I test relay switch
neyod
Subscribe to:
Posts
(
Atom
)