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

  • 180 Answers

SOURCE: lg 500g crt monitor problem


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

Happy trying

Posted on Apr 10, 2008

Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

Lg Flatron-w1942T Problem: Black display plz help when i swich on the monior it shows video for single moment and then black .au io is ok my video card is ok

Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Sep 01, 2016 | LG Computers & Internet

1 Answer

Dell 21 inch p1130 no power on

check the fuse and cable.
check the SMPS out put (100v, 85v, 18v, 12v, etc)
Check the Horizontal out put transistor
check horz. driver transistor

Apr 15, 2011 | Dell P1130 21" CRT Monitor

1 Answer

Viewsonic VX924 monitor SMPS failed. Replaced all bad capacitors and have found that one pair of inverter driver transistors has failed. They are marked as DKQR (They are apparently Rohm 2SC4672...

When the DC filter caps no longer filter out high frequency AC, that AC will be fed through out the circuits and cause damages such as the inverter frequency will be running at the wrong frequency and caused overheating.
The service manual does not show the sch of the power supply/inverter board because it is not designed by Viewsonic.

Mar 27, 2011 | ViewSonic VX924 19" LCD Monitor

1 Answer

Checked all but not helpful. when i disconnect high voltage connectors from supply unit then power led goes stable but no display

This is typical as the SMPS power supply is shorted when the connector is on to the board. when you remove the connector, the short releases and the power resumes as the SMPS has a high current cut off for protection.
So the easy way out is to have a multimeter and check the power line to the circuit disconnected to check out the shorted driver. Once you have zeroed in to the component release and connect power supply to confirm. Now replace the shorted component.
make sure that any high voltage in circuits are discharged when you use the ohmmeter in the circuit.

Oct 11, 2010 | Philips Computers & Internet

1 Answer

Found them

If you are referring to the C5707 inverter driver transistors, you can test them in circuit with an ohmmeter. Usually one pair will show shorted although only one may be actually shorted. Normal procedure is to replace the pair that shows in circuit short. If you do not resolder the transformer connections your transistors will short again.
Monitor Mike

May 30, 2008 | BenQ FP737S-D 17" LCD Monitor

2 Answers

Monitor problem

the horizontal output transistor appears to be short-circuit.
the clicking noise is the SMPS power cycling as it detects a circuit fault.
the real problem here is finding out what killed the HOT, flyback transformer is the usual culprit.
Personally, i'd ditch this monitor. good quality flat screen CRTs can be had for almost nothing these days and the cost to repair this will exceed the cost of a good 2nd hand 21-22" sony/mitsubishi unit

Apr 25, 2008 | Gateway FPD2275W LCD Monitor

1 Answer

Lg 500g crt monitor problem


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

Happy trying

Apr 01, 2008 | LG Studioworks 45 14" CRT Monitor

1 Answer

Monitor not Display

Hi Rey,

Hope this helps you like what I did to resolve this kinda problem. If you can manage to open the chassis/cover check first if the HOT (horizontal output transistor) is good, if good check the SMPS (switching mode power supply) primary and secondary side if there are short filter capacitors, diodes, transistors and open resistors. Major faults to consider is by checking the load of SMPS, control circuit, driver circuit, feedback ckt.

Please let somebody to assist you (a certified technician) how to open the chassis safely due to electric shock. Please be guided accordingly.

Best regards,
Rosener Guyano

Jan 30, 2008 | MPC Computers AOC 7F 17" CRT Monitor

2 Answers

Dead set lg studio works v452 monitor

lg g505 this moniter 5 or 10 mnt woking then hot transister is damaged why this problem ?

Jan 26, 2008 | LG Studioworks 45 14" CRT Monitor

1 Answer

Lg 5552 v set is dead

try to resolder all points in fbt including fly back trans itself area also resolder the crt pcb area i had the same problem the reason was cold soders also put a good 2sc5297 for hor out.

Dec 02, 2006 | LG Studioworks 552V 15" CRT Monitor

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

18346 Answers

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

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

Answer questions

Manuals & User Guides