Re: lg42lg7000-za schematic needed
I have one of these sets, which has failed, I have checked the power supply, all voltages are present all capacitors have been checked with LCR meter and are good, when in standby led is on when you press on button the red led pulsates and goes out this coincides with all voltages appearing on power supply pins 24v to inverter board is present 16v 12v & 5v all present feeding main board.. I have checked the inverter transformers with ring tester all OK also checked mosfets all good. I get peeps when pressing any side buttons, but no backlight...
TEDDIBEAR
Member
Last Activity: 11-21-2023, 02:27 PM
Joined: 10-02-2014
Location: cullompton devon
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Linsar 55UHD8000FP Remote
Can anyone help I have been unable to find a replacement remote or even compatible for this smart tv. I know it is a Vestel clone so wonder if any other remote would have the same frequencys?I have purchased replacement remotes which are identical to look at but do not work. -
Re: Polaroid tlu-01541cu s/b light on set dead
The Tcon board is part of the LCD screen, attached with film connections.
John...Leave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
I have gone one step further linked a Ik resistor between B/ON & P/ON still zero volts on B/ON, left resistor in position disconnected B/ON feed from main board now have back light working, so I now have a glowing screen no sound no display so it looks like I have hit the buffers
unless you have any suggestions.
John...Last edited by TEDDIBEAR; 02-05-2021, 07:43 AM.Leave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
Have checked resistance between B/ON pin and ground = 10k
BL-ON is fed from transistor Q209 on main board there appears to be no volts on E-B-C of this transistor, the transistor Q208 does have 5 volts on collector nothing on base or emmiter, but with out a circuit diagram it is hard to find where the switching signal is comming from.
If I were to link B/ON to P/ON do you think that would be worth trying?
john...Leave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
Bud
After reading your brilliant text on the other thread, I set to work rechecking my work so far I realised I had ordered and fitted the wrong Mosfet looking at the old devise with a microscope as the markings were soo bad the 3 turned out to be a 8, the device I fitted was a AOD403 P fet should have been a AOD408 N fet.fitting a N fet brought the following readings, on switch on, +5 volts on SB terminal, pressing standby button I get +5 volts +12 volts, +3.3 volts on P/ON, +5 BRI, but nothing on B/ON. any ideas?
J...Leave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
Thank you for your replies.
This is the state of affairs
switch on at main switch I have +5 volts on +5 volt terminal pin, I also have +5 volts on the SB standby terminal, no +12v, when I press Standby button on remote I get +5 volt on P/on terminal pin and then +12v on +12v terminal pin,
I get nothing on B/on or Bri terminals. hope that makes sence, should I only have +5 volt on SB terninal and zero on +5 terminal on switch on and should the +5 volt only appear when Standby button is activated?.
If you then...Leave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
This is all 14 pins as in picture 6, when mains is applied to power supply panel I only get +5 volt on + 5volt pair when I press sb button on remote I then get +12 volt but nothing on any other of the pins if I then press sb button on remote +12 volt remains until you unplug and start again.
JohnLeave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
Voltages are as follows
+5v-+5v =5v
SB -SB = 0v ?
GND-GND = 0V
GND-P/ON = 0V ?
BRI -B/ON = 0V ?
GND-GND = 0V
+12V-12V = 12V
All ? unable to trace source
Thanks
JohnLeave a comment:
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Re: Polaroid tlu-01541cu s/b light on set dead
Pictures uploaded screwdriver indicates relevent items.
John...Leave a comment:
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Polaroid tlu-01541cu s/b light on set dead
Fault on this set was bad caps as usual which were replaced,on switch on no volts, second fault blown AOD403 p channel mosfet when replaced returned 5V rail and standby led, pressing on button returned 12v rail, I still have no backlight or any responce except plop from speakers, I do not know what voltages I should be getting on these connections BRI,B ON,P ON,or SB or their source, I do not think the backlight oscillator circuit is being switched on as no volts on IC pin 12 vcc,
Not having a circuit diagram it is difficult to know where to look, any help would be appreciated, I think... -
Re: Still clicking after replacing eeprom Samsung LE40M87BDX
Just to add my five peneth,The Samsung I encountered did not have any bulging caps as seen in many forums,all the caps were replaced as a mater of course, still relay clicking, I then checked the 10uf and 47uf on the power board they all showed very high ESR one was completely OC, so all caps replaced on power board, still clicking relay, I then noticed there were horizontal flashes between relay switching on and off, looking on the mother board for any clues I noticed a charing of two smd resistors R1131 R1132 68ohm,...Leave a comment:
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Re: ESR meter upgrades
I think the problems with the menu side were the same, having said that I can not read Russian but the menu did not seem to change when a selected item was pressed. Your first T4 worked perfectly as did the second T4 as far as diagnosis were required the second one had smaller fonts and very fast, the problem seems to be selection from the menu pressing button.
John...Leave a comment:
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Re: ESR meter upgrades
Hi stj
thank you for your update I am afraid I am still unable to select from menu
here are the results. + when a test is made it stays on the screen for a split second too quick to read...Leave a comment:
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Re: ESR meter upgrades
There is only S1 start button on this device.apart from the addition of the encoder.
could it be the 16mhz crystal causing the problem of selection.?
I have checked the voltage on the start button which shows 9 volts collapsing to .7 volt on press on then returning to 2.7v on the live side powering the display, returning to .7volt every press, voltage on PD 7 drops from +5 volt to .7 and returns to 5+ on release of the button.The encoders center pin is to chassis
each leg is supplied from 5+ rail via 10k resistor and PD1...Leave a comment:
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Re: ESR meter upgrades
Have tried many combinations holding button down from a quick click to 30 seconds, I was wondering if there is an enable contact on the chip that could be switched.
John...Leave a comment:
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Re: ESR meter upgrades
Thank you all for your input.
I have now found firmware for my LCR_T_4_H as stj has suggested it uses T4 stripgrid, every thing seems correct as far as component diagnostics with the 16mhz crystal and encoder fitted.
The problem I have is I can select items from the menu with the encoder but can not open them, with any amount of pressing the button, any ideas.?
Thanks Gabiz I have tried that one with no luck. Sorry thumb nails are bright and poor focus unable to reduce contrast.
John...Last edited by TEDDIBEAR; 12-16-2017, 04:40 PM.Leave a comment:
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Re: ESR meter upgrades
Have just received encoder and fitted to my LCR_T4_H along with two 10k & two 1k resistors, also changed 8mhz crystal to 16mhz but seem to be unable to find any firmware that will work the \LCR-T3,4_v1.12k_r660_ENC13.zip\LCR-T3,4_v1.12k_r660_ENC13\ works of sorts showing capacity at double the value
and locks up as soon as you move the encoder to blank screen you then have to disconnect the battery to reset it. any help will be appreciated.
John...Leave a comment:
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Re: ESR meter upgrades
Is there a way of changing the language easily as I would like to give this firmware a go unfortunately it has Russian text.
John...Leave a comment:
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Re: ESR meter upgrades
This is the firmware that has given me the vext screen.
LCR_T4StripGrid_Ver736Ru_8x16t_Vext_Encoder_16MHz.zip\
If I could get the english version I think it may work on my LCR-T4-H.
John...Leave a comment:
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