Well this is my first post so please be gentle. I fix tv's as a hobby. It gives me satifaction if I can save a plasma or lcd from the dump. With everyones help on this forum, I have fixed a bunch of tv's just by reading the posts. My question is probably simple, but I am working on a 60PV450 LG plasma with sound and no display. I have all the proper voltages on the power supply, but checking the Vscn on the Y sustain, I only measure about 23 volts. I know it should be about 150 volts. I did remove both buffers and its still at 23 volts. I would assume the voltage is generated on the Y sustain in which case I was going to be looking at replacements. I did read that this particular plasma had trouble with the main board. If any one of you pro's out there could let me know if I am on the right track, it would be appreciated. I would like to fix at component level but everything seems to check out--nothng shorted so I thought the best to replace the y board. My Vs is 201 and Va is 55 and the tv stays on with sound. Thanks again for any help on this.
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Re: 60pv450 LG plasma
I will be gentle in telling you that posting pictures of the boards etc would be VERY helpful...Proud owner of dozens of broken TV's and many,many,many boards.
Our website and passion:http://hollenhundshepherds.com/ -
Re: 60pv450 LG plasma
I will attempt to post pictures, but I was mostly interested in the theory behind Vscn voltage. Is it always produced by the Y sustain or is it started from another board. ThanksComment
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Re: 60pv450 LG plasma
Almost always Y-sustain. It is floated above the Y-sustain FGND output (the main output to the plasma panel) and is used by the buffer boards to select the row to apply pixel data to. The image is loaded into the panel using this, then "sustained" (made to light up) in a number of sequential sub fields (the Z-sustain drives the opposite end of the panel but it is only necessary to select one side using the buffer ICs), which gradually builds the image on the panel.
Vscn typically in 130V to 150V region.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: 60pv450 LG plasma
Thank you TOM66, so I guess my best attempt to repair this because Vscn is only 23 volts, would be to replace the y sustain. The voltage stays the same with buffers connected or disconnected.Comment
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Re: 60pv450 LG plasma
Yes, that would be a reasonable approach.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: 60pv450 LG plasma
I use the 60PV400 and for a cheaper plasma its pretty nice and I have it all dialed in too.
The parts are pretty cheap for these and from what I read the Ysus is a common failure on these units.
Mine has low hours on it and I bought it used.
Good luck, let me know if you want my Expert 2 20p IRE calibrations (you can tweak and tune them to fit your viewing pleasure).Comment
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Re: 60pv450 LG plasma
I've never really liked LG plasmas for the black level but the brightness and colour accuracy is stunning. Build quality is also pretty good. You can tweak the black level; I've managed to reduce it to about half by my eye on a 50PS3000. Adjust SetUP, SetDN, -Vy, Ve and Vs to tweak it. LG are extremely generous in how they drive the plasma panel so there's lots of room to lower it without causing issues.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: 60pv450 LG plasma
Not to clutter up his repair thread, I might have to have you tell me more about this so I too can get some deeper blacks.
Funny this 2008 F5084 Sammy I got here destroys this LG as far as black levels go. Pretty close as far as everything else goes. The LG kills the Sammy in refresh though 600hz vs what ever the Sammy is. I do got to admit the FPT-5084 is a beautiful beast. The one I got sitting here at 11k hours on it and not a single sign of burn in.
Just need to work on the PS as it clicks several times before coming on.Comment
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Re: 60pv450 LG plasma
I will try to get a Y sustain and will post my results. Thanks for your help, I feel more comfortable replacing the Y board with the info I got.Comment
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Re: 60pv450 LG plasma
Thought I would update my repair. I got a Y sustain board for $30.00 and decided to change out both buffers for $44.00. I still had no display and very little Vscn. Scratched my head and resumed checking. I guess I made an error when checking voltages on the power supply. I had 55 volts on Va and 201 on Vs. But heres the catch. I was checking on the Z sustain connector for voltages which is where I reported my readings. The power supply has two identical connectors, one to the Z and one to the Y. The Y connector only showed .8 volts for the Va. I knew the 55 volts had to just bridge from one connector to the other so an inspection thru a magnifying glass showed a hairline crack half way between the power supply. I scraped to get to the copper trace and then solder bridged the crack and guess what? It works!!! Sometimes I guess you can assume things about readings but I learned a valuable lesson and maybe spent $74.00 for nothing other than a learning experience. Thank you everybody for your replies. Hope my reply helps somebody out thereComment
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Re: 60pv450 LG plasma
Yes, $74.00 is a cheap learning experience. Never thought to check both connectors, taught me a lesson. I usually keep the parts for spares or rob parts off them. I hate selling electronics on ebay as you usually get a buyer that just buys parts to check if it fixes and then gets a refund. Just a hassle.Comment
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Re: 60pv450 LG plasma
I got the same issue on my LG. Going to have to reference your posts when troubleshooting. Thanks for the followup.Comment
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Hi, I was wondering if there's anyone here with experience on the LG50PJ350 plasma or similar models? When it came in, it had 7 shorted mosfet outputs on the Y-sustain board, Q02, 04,11, 22, 24, 26, and 28 were all dead shorted. I replaced them with the exact same type, checked their surrounding area for other open and shorted components and didn't see any further problems. But as soon as I hit the power button on the remote, I had a loud Pop! and Q22, 24, 26, and 28 are shorted out again. The other 3 seem to have survived. Someone on another forum had suggested the possibility of a shorted panel.... -
Hello I'm struggling with this old plasma TV and its SC board, TNPA4393, I've measured the SU/SD buffers, every IGBT and transistors, gate drivers, SMD diodes, optocouplers etc, no shorts or suspecting measurings, at least with they soldered on the board.
VSUS - 187V
VDA - 75V
VE - 130V
VSET - 320V
VAD - (-149V)
16V_F
5V_F A/B
15V
All voltages are normal except for VSCN, which according to the service manual is supposed to be 145V+-4V, it is always 205V.
VSCN voltage is fixed, generated and measured from VAD... -
Hi everyone,
Brought a non functionnal PS5. Apparently only a bad PSU...
No beep, nothing.
After some tests i found this :
- PSU is fine (12 volts stable)
- 12 volts line is shorted
- DA9065 was fried, F7003 also => Replaced both of them, short is gone on 12 volts line, no dead short anywhere else.
- By the way, nothing change. No signal, no power, no beep.
Mesuring all rails with my workbench psu (12 volts input)
- 0.00 amp drawing
- 12 volts, 5 volts, 2 volts, 1,15 volts are presents (suppose new DA9065 do is... -
Hi folks,
I have a Samsung plasma tv PL51F4500. It works fine, image is good, but it shocks me a little when i touch it or touch a connect hdmi cable. So my concern is mostly for anything i connect to it, my notebook etc. Interestingly, i had stopped using it and went to turn it on yesterday and it basically doesn't 'shock' me anymore. The observation here is that its a lot better than when it was in regular use. It was pretty salty!
This model has an integrated sustain board with the main power supply. I repaired it about 2 years ago (mosfets) but i may have missed... -
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