Question about LG Studioworks 570LE (White) 15.1 in. Flat Panel LCD Monitor

Open Question

H out transistor get short

The model no: of my LG TV is RF-21 FA20KV.
SMPS is ok.
found h out transistor get short circuited.
i removed transistor; make sure that all supporting components are normal..
insert a new transistor with a new LOT.
Switch on the system with disconnected the Motherboard from CRT etc.
heard "chick" sound and sound of the h out oscillation.
then make all connections . after switch on the system; with in three seconds hout transistor get again short cktd.

Posted by on

1 Suggested Answer

jemmyrash
  • 180 Answers

SOURCE: lg 500g crt monitor problem

Hi,

Try checking B+ coil , may be the coil have shorted .

Happy trying

Posted on Apr 10, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Lg crt 29 inch tv wont start


The frame amplifier, like the line amplifier, will not work if there is no output from the oscillators for them to amplify.

Early 405 line sets didn't have a frame oscillator as they used the sine wave from the AC mains but I believe the later sets needed a frame oscillator and a sync signal from the rf demodulator to prevent instability.

Transistors rarely fail by themselves and it is often external factors that cause them to overheat and fail and an essential part of the repair process is discovering what factors caused the initial problem. Modern circuits use a lot of multi-transistor dc coupled stages and it is often the bias of an earlier stage that is the culprit.

The frame output transformer is usually very robust and much less likely to fail than a line output transformer. I suggest you ensure the correct operation of the oscillators before going any further.

Aug 30, 2016 | LG Televison & Video

1 Answer

UndefinedI've checked a Panasonic crt color tv model TC-21fj20p, and I find a hard way to discover the cause of the problem until now.. The set has a good primary voltage supply. No problem with the IC...


Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
Any short circuit at the horizontal output section circuit will shut down all the secondary SMPS voltages, as there is short circuit protection circuit to all Sony TVs.

Oct 28, 2014 | Televison & Video

1 Answer

Blown fuse in tv power supply


Check all the other components; diodes, transistors etc:- at the main power regulator stage circuit for any damage. If the fuse should blow, there should be a short circuit with the related power regulator [SMPS] circuit. If you wish to get more details, check the site linked here. Surf the site in "MOSAIC" view.
http://electronicshelponline.blogspot.com/

Jan 22, 2014 | Televison & Video

1 Answer

When i switch on 21 inch lg tv the voltage in power supply section continuously falls to 0.2 and tv wont power on


Short circuit at the main board. Check the horizontal scan output transistor for short circuit. Check its collector to emitter, or collector to base for short. Replace this transistor and check. If you wish to get some details, check the site linked here. Pull up older posts. Check the site in 'Mosaic' view. It will make search easy. http://electronicshelponline.blogspot.com/

Jan 17, 2014 | LG Televison & Video

1 Answer

Hitachi TV model C21-rm25s-192 power supply transistor and fuse blow off just after replacement. other components of the power supply seem to be ok. what should I do?


The SMPS - power supply is critical of the generated frequency , load trip and high voltage. So if the power transistor has blown then you must check the reason for the failure before the new one is put into the circuit. Check the DC voltage, check the rectifier, storage capacitor and the frequency oscillator. check for short in the SM tranformer , feedback optocouplers or a possible short in the main circuit.
Please check the link below for help:


http://www.fixya.com/support/r5826301-working_switch_mode_power_supplies

Feb 08, 2011 | Televison & Video

2 Answers

Sharp tv primo 21`inch turn on red light only


check your horizontal transistor maybe it's shorted replace horizontal transistor or maybe the fusible fuses are open check for open resistors at the horizontal section of the circuit.

Dec 22, 2010 | Sharp Televison & Video

1 Answer

LG CRT HDTV Dead no picture


if you have the b + acording the manual then you loose it
could be many things like the vert. circuit, the crt itself or
the flyback,

Aug 06, 2008 | Televison & Video

1 Answer

Sony Tv Model KV2162 M9


The SONY 2162 is a Old Warhorse. It was manufactured nearly 20 years ago. If the set is dead, and if no one has tampered with it, it can be repaired. One problem I found often in the 2162is that it's mains ON OFF switch failed regularly. check that.If you have knowledge of Solid State Electronics, please carefully open the Back Cover and first check the fuses. If they are ok, then check the SMPS switching transistor. If it is short circuited, then replace. Also check the Horizontal Output Transistor at the same time.

Aug 26, 2007 | Televison & Video

Not finding what you are looking for?
Computers & Internet Logo

Related Topics:

386 people viewed this question

Ask a Question

Usually answered in minutes!

Top LG Computers & Internet Experts

Brian Sullivan
Brian Sullivan

Level 3 Expert

27725 Answers

Les Dickinson
Les Dickinson

Level 3 Expert

18377 Answers

k24674

Level 3 Expert

7993 Answers

Are you a LG Computer and Internet Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...