![]() |
|
|
Thread Tools | Display Modes |
![]() |
#21 |
Badcaps Veteran
Join Date: Jan 2013
City & State: midwest
My Country: U.S.
I'm a: Knowledge Seeker
Posts: 8,186
|
![]() LOL, I meant is there voltage at the spot on mainboard where you expect it without the lvds cable hooked up.
|
![]() |
![]() |
![]() |
#22 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() Sorry, my mistake. Posted the wrong picture. Can you give the numbers on the two IC's in the red boxes. The yellow boxes have voltage regulators. Can you measure the voltage on the 3 pins of each.
__________________
Willing to help but I'm no expert. |
![]() |
![]() |
![]() |
#23 |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() |
![]() |
![]() |
![]() |
#24 |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() |
![]() |
![]() |
![]() |
#25 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() Can you give the voltages on the IC pins. I suspect one of them may have the 12V but is not switching through to the Tcon.
|
![]() |
![]() |
![]() |
#26 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() |
![]() |
![]() |
![]() |
#27 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
11.9 --- 0.0 11.9 --- 0.0 11.9 --- 0.0 11.5 --- 0.0 Middle IC 1.1 --- 3.5 1.1 --- 0.0 23.6 --- 3.2 23.6 --- 1.4 Bottom IC 9.9 --- 2.3 9.9 --- 0.0 23.6 --- 12.7 23.6 --- 9.9 Top one looks like it might be the culprit? It's also the closest to the LVDS cable connection point. |
|
![]() |
![]() |
![]() |
#28 |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() |
![]() |
![]() |
![]() |
#29 | |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() Quote:
Last edited by dick_barton; 10-23-2019 at 05:43 AM.. |
|
![]() |
![]() |
![]() |
#30 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
SOP-8L (top) 1. S - 11.9 2. S - 11.9 3. S - 11.9 4. G - 11.9 5. D - 0.0 6. D - 0.0 7. D - 0.0 8. D - 0.0 SOIC-8 (middle) 1. S2 - 1.4 2. G2 - 3.2 3. S1 - 0.0 4. G1 - 3.5 5. D1 - 1.1 6. D1 - 1.1 7. D2 - 23.7 8. D2 - 23.6 SOIC-8 (bottom) 1. S2 - 9.9 2. G2 - 12.7 3. S1 - 0.0 4. G1 - 2.3 5. D1 - 9.9 6. D1 - 9.9 7. D2 - 23.7 8. D2 - 23.7 Hope I've got them right. ![]() Last edited by Stuckster; 10-23-2019 at 06:04 AM.. |
|
![]() |
![]() |
![]() |
#31 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() I believe the gate voltage should be at least 1.5V lower than the Source voltage so it looks as though the IC is not being switched on to allow the 12V through to the Drain which is probably the 12V supply for the tcon. You can check this out. With the set switched off check the resistance between the fuse on the Tcon and the Drain of the P3056LS
Could you also check the resistance between the Gate and Sourse and Gate and Drain. |
![]() |
![]() |
![]() |
#32 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
P3056LS 1. S - 11.9 2. S - 11.9 3. S - 11.9 4. G - 11.5 5. D - 0.0 6. D - 0.0 7. D - 0.0 8. D - 0.0 |
|
![]() |
![]() |
![]() |
#33 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
Resistance between Gate and Source is 33 (meter set to 200k Ohms) Resistance between Gate and Drain is 90 (meter set to 200k Ohms) I'm only a novice when it comes to this stuff. So thanks for your patience. ![]() |
|
![]() |
![]() |
![]() |
#34 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
|
![]() The resistance from the Tcon fuse to Drain being 0.001 means that P3056LS should be providing the 12V Tcon supply.
The other resistance readings, 200K ohms means there is no internal short circuit from gate to the source The problem is that the IC is not being switched on. Can you take a really sharp photo around that IC to try and see what the Gate track is connected to. |
![]() |
![]() |
![]() |
#35 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
Now the first thing you're going to say is, that's a different IC! Which is true. I should explain that I currently have two mainboards (same model). Lets call them A and B. Board A is the original board that came with the set. It failed and has too much wrong with it to resurrect. Board B is a replacement board that I bought "in used working condition". It is the board that I have been talking about in this thread. All the voltage and resistance readings have come from board B. When you asked for the IC numbers I assumed (wrongly) that the parts on each board would be identical. It was easier to give you the part numbers from board A since I had it on the desk and could easily take the heat sink off etc. Apologies. Nevertheless having looked up the specs for the PMK50XP IC on board B (the one in the close up photo) they appear to have the same specs and function. Last edited by Stuckster; 10-23-2019 at 06:00 PM.. |
|
![]() |
![]() |
![]() |
#36 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,206
|
![]() https://www.badcaps.net/forum/attach...2&d=1571874353
SOP-8L (top) 1. S - 11.9 2. S - 11.9 3. S - 11.9 4. G - 11.9 5. D - 0.0 6. D - 0.0 7. D - 0.0 8. D - 0.0 So if you check the resistance between the T-CON fuse and D pin of Q1, it shows about the same resistance of the meter's probes resistance?
__________________
Never stop learning Basic LCD TV and Monitor troubleshooting guides. http://www.badcaps.net/forum/showthr...956#post305956 Voltage Regulator (LDO) testing: http://www.badcaps.net/forum/showthr...999#post300999 Inverter testing using old CFL: http://www.badcaps.net/forum/showthr...er+testing+cfl Tear down pictures : Hit the ">" Show Albums and stories" on the left side http://s807.photobucket.com/user/budm/library/ TV Factory reset codes listing: http://www.badcaps.net/forum/showthread.php?t=24809 |
![]() |
![]() |
![]() |
#37 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
With the meter set on 2k Ohms it 's reading 0.001 Ohms to all D pins. With the meter set on 200 Ohms it 's reading 1.5 Ohms to all D pins. |
|
![]() |
![]() |
![]() |
#38 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,206
|
![]() https://www.badcaps.net/forum/attach...2&d=1571874353
Put DC Volt meter black lead on the chassis, Red lead to the Base pin of Q2 then turn the TV ON and OFF (wait 5 seconds between toggling) to see if the Voltage on the Base pin of Q2 changed state when you toggle the TV ON and OFF. |
![]() |
![]() |
![]() |
#39 | |
Member
Join Date: Oct 2019
City & State: Sydney
My Country: Australia
I'm a: Knowledge Seeker
Posts: 40
|
![]() Quote:
|
|
![]() |
![]() |
![]() |
#40 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 39,206
|
![]() https://www.badcaps.net/forum/attach...2&d=1571874353
Emitter pin (Top) is connected to R125/C181 Collector pin (Middle pin) is connected to R126 Base is the bottom pin. |
![]() |
![]() |
![]() |
Thread Tools | |
Display Modes | |
|
|