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Goodmans GTV42P3 42" Plasma TV - Power Board Repair
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Fri Nov 21, 2008 7:12 am    Post subject: Goodmans GTV42P3 42" Plasma TV - Power Board Repair Reply with quote

Good Day All.

I have a 3 year old Goodmans GTV42P3 42" Plasma TV, that has stoped working.

It was working fine one day, and the next nothing, will not power on, not even the standby light.

I removed the back pannel from the TV to gain access to the main power board, I found that two 5watt resistors had poped on the mains input before getting to the bridge rectifier, I also remove the rectifier to test if it was ok, and it seems to be ok, before refitting the rectifier, I used my ohm meter on the on the PCB where the rectifier + & - would be, and found to have a dead short.

I then removed two "20N60C3 N-channel MOSFET 20.7A 650V" And the dead short was gone, I then used the ohm meter across each pin of the mosfet, and not matter what way I tested it was a dead short.

I don't know how you are ment to test a mosfet, but I am sure that I should not get a dead short on each pin.

I can get all new new parts from RS.

(R103) - 15ohm 5Watt Resistor (199-7719) £0.38 Each, 5 Pack | £1.90.
(R102) - 22ohm 5Watt Resistor (199-7725) £0.38 Each, 5 Pack | £1.90.
(Q101 & Q102) - 20N60C3 N-channel MOSFET 20.7A 650V (462-3449) £3.33 Each | £6.66.
(D102) - PH967C6 Rectifier (2509692021) £7.90 + £10 handling charge | £17.90.

But before I go and order and new parts and possible blow them up, is there any other tips or guides to find out what might of made thease mosfet's go bad?

Thanks for your time.


Last edited by Mad Professor on Sat Nov 22, 2008 9:37 am; edited 4 times in total
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Fri Nov 21, 2008 8:39 am    Post subject: Re: Goodmans GTV42P3 42" Plasma TV - Power Board Repair Reply with quote

Mad Professor wrote:
Good Day All.

I have a 3 year old Goodmans GTV42P3 42" Plasma TV, that has stoped working.

It was working fine one day, and the next nothing, will not power on, not even the standby light.

I removed the back pannel from the TV to gain access to the main power board, I found that two 5watt resistors had poped on the mains input before getting to the bridge rectifier, I also remove the rectifier to test if it was ok, and it seems to be ok, before refitting the rectifier, I used my ohm meter on the on the PCB where the rectifier + & - would be, and found to have a dead short.

I then removed two "20N60C3 N-channel MOSFET 20.7A 650V" And the dead short was gone, I then used the ohm meter across each pin of the mosfet, and not matter what way I tested it was a dead short.

I don't know how you are ment to test a mosfet, but I am sure that I should not get a dead short on each pin.

I can get all new new parts from RS.

1x 15ohm 5Watt Resistor (199-7719) £0.38 Each, 5 Pack | £1.90.
1x 22ohm 5Watt Resistor (199-7725) £0.38 Each, 5 Pack | £1.90.
2x 20N60C3 N-channel MOSFET 20.7A 650V (462-3449) £3.33 Each | £6.66.
1x PH967C6 Rectifier (2509692021) £7.90 + £10 handling charge | £17.90.

But before I go and order and new parts and possible blow them up, is there any other tips or guides to find out what might of made thease mosfet's go bad?

Thanks for your time.
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Fri Nov 21, 2008 8:51 am    Post subject: Reply with quote

Sorry for the 2nd post I hit quote and not edit, Doh! Embarassed

Best Regards.
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Fri Nov 21, 2008 3:31 pm    Post subject: Reply with quote

I have been looking over this unit more today, and eveywhere I look LG stickers and part numbers keep on poping up.

On the back of the screen is a few stickers, Saying "PDP42V6####" and "PDP42V64000.


LGE PDP 040218
Model 42V6
Board ZSUS


LGE PDP 040217
Model 42V6
Board 42V6_XR


LGE PDP 040217
Model 42V6
Board 42V6_XL


LGE PDP 040110
Model 42V6
Board YSUS


LGE PDP 040308
Model 42V6
Board YDRV_BTM


LGE PDP 040308
Model 42V6
Board YDRV_TOP

Power Board
USP490M-42LP
Rev. A
UNICORN CO., LTD
Made In Korea.

Here are a few pictures of side the unit.

View with back cover removed.


View of main power board.
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Fri Nov 21, 2008 3:55 pm    Post subject: Reply with quote

Just found the Main Power Board schematic.

http://monitor.net.ru/forum/files/usp490m-42lp_601.pdf.

I still would like you advice on what else I should test before ordering new parts.

Best Regards.
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Old Bassid
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PostPosted: Sat Nov 22, 2008 8:17 am    Post subject: Plasma fault Reply with quote

The standard fix is to replace panels-eg Zsus,Ysus etc- no one fixes to component level- the manufacturers discourage this- but if I had a fault in a plasma, & it was my own, I would fix it at component level- but I am quite happy with my crt Philips 1990 26" ctv- in my opinion plasmas are an aberration-as are lcd,s- but new developements are coming(compact crt,s) o'leds,etc).
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Mon Nov 24, 2008 10:37 am    Post subject: Reply with quote

Well over the weekend I had very little to do and had not yet ordered any new parts.

So I tought to my self lets see if I could get it to power up at all.

With knowing that Q101 & Q202 where totaly dead and had a short across all three pins, i know that there was nothing I could do with them.

So I had a look a D102, Only one half of the diode had failed, so I cut off the pin to the failed side, and soldered it back into the power board, I did not have any small 5watt resistors that would fit, but I did find some spare 10watt ones, so I soldered them in.

I then powered up the unit and the standby LED came on, I left it sat on standby for a few min just to make sure nothing got hot, or let off smoke.

After a few mins I then pressed the power button on the remote, and the TV fired into live, I have got picture and sound, I have only tested the scart inputs at this time, but is working well.

So I will be ording all the new parts today, and just hope something does not pop the new Q101 & Q202, eventho it is working without them.
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Old Bassid
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PostPosted: Wed Nov 26, 2008 8:48 am    Post subject: Mad Perfessor Reply with quote

You are not just mad but totally insane, not to mention delusional(Isaid not to mention!!!)- anyway, get off & stop wasting genuine posters time!.
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Mad Professor



Joined: 14 Sep 2008
Posts: 25

PostPosted: Wed Nov 26, 2008 9:34 am    Post subject: Reply with quote

Old Bassid: what on earth do you mean by your reply?

Are you trying to say that my TV is not working? if so I invite you and anyone else who thinks it's not working to come and view it working and even open up the back and see that Q101 & Q202 are not on the main power board.

I have replyed to this post, and keep updating it with my finding and progress so to try and help anyone else who it having the same problem as me.

I was not expecting it to work without Q101 & Q202 fitted, but it does work, the only thing I can say is that the sound volume is lower then it used to be, and when the screen refreshes or go's from colour to black you get multicoloured pixels in that area for a few sec's.

I have watched a 2 hour flim on this TV without Q101 & Q202 fitted, With no problems.

But as said before I will be replacing all the dead parts with new, so thats R102, R103, D102, Q101, Q102, so once all the new parts are fitting the TV should be back to normal.
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Old Bassid
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PostPosted: Thu Nov 27, 2008 6:28 am    Post subject: Reply to a [email protected]#$%^n [email protected]#$%^R. Reply with quote

Yes MAD- we all would like to come & see your LG plasma that defies the physical laws(according to YOU)- so if you would post your address, you may expect some visitors(among them LG engineers)- after all, if they can do this at the factory!- think of the savings! Kind regards from a [email protected]#$%^n Old Bassid.
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