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Hi everyone,

I'm trying to repair a philips 55PUS7809 with power but no picture.

After disassemblying it, I found out that a Q3 transistor had blown away on the T-Con board réf. 6870C-0502B (LG Display)

Anyone could help me finding the diagram of this board?


Thanks a lot.

04/07/2019 : I ordered the board on aliexpress.com

10 days after, I received a refurbished board with one inductor case broken. Also I had to pick up a LVDS lever from the old board to replace one missing 
on the new board.

After plugin everything back, Tv is working again !!

Bought 1400€ 5 years ago, I'm happy to fix it with only 8€ (shipment included)

THanks Aliexpress !!!

 

Sziasztok! A fent nevezett tv-hez kérek javítási tanácsokat. A hiba jelenség: ki veri a biztit, és a táp meghajtó tranyó (ON 4827, cserélve BUT 12-re) azonnal elszáll. A tranyót kiforrasztva, bekapcs. után a primer fesz. rendben (285V), és a készenléti táp is elindul. Köv. lépés: új BUT 12 be, bizti helyére 60W-os izzó. Az izzó közel telj. fénnyel világít,(a tv-re így csak kb. 60V eik) de a táp el kezd működni (természetesen a szekunder kőrben a névleges feszültségek töredékei, kb 40% mérhetők) Egyszerű eszközökkel mérve egyéb zárlatos, vagy szakadt alkatrészt -idáig- nem találtam, ja és a BUT 12 kollektor "hidegítő" 1,5nF cseréltem, de hiba továbbra is fenn áll. Előre is köszi.

Üdvözletem! Philips A02EAA chassis függőleges védelmét hogyan tudom kikötni? A hibajelenség, hogy 10-20 perc járatás után a kép alja felugrik középig, és középen a sorméret is lecsökken, mintha az E-W is leállna. Ilyenkor képet nem látok cak visszafutás csíkokat. Persze ezt csak egy pillanatra látom, mert a védelem leállítja. Pár másodperc "feketeség" után visszajön a kép, megint megy 10-20 percet. Függ ic-t cseréltem, -15V folyamatosan van. A segítségért előre is köszönet! Üdv!

Dear Expert
The details of my TV is as follows

1. Philips 40PFL4707/F7 Manufactured March 2012
2. SMPS Board BA21P6F01 01 1
3. SMPS board has a sticker that says A21P6MPW C 7219720
4. This is a 110v Mains Supply TV sold in USA
5. I imported this from USA into my country where we have 230V.
6. I have a simple winding transformer that converts 230v to 110v

The TV has been having this problem.  Here are the steps
1. Mains power on
2. Front panel white led blinks 6 times
3. Philips logo display
4. TV shuts down immediately
5. Nothing happens.  If i press power button on TV or remote nothing happens
6. Have to power off and then wait for few minutes to experience same repetition.

Last two days, tried several times, only once the TV started and after 10 minutes it did auto shutdown as there was no input signal connected.

Does this indicate issues with SMPS or main cpu board ? Even if its faulty, how did it start once ?

More testing done as follows
1. Removed all connectors. Cleaned all three pcb with liquid cleaner. Cleaned all connectors externally and internally ( holes) using painting brush. Allowed everything to dry.
2. Reconnected
3. Started. This time, went past the Philips logo. I could connect a macbook via HDMI and play youtube videos on the TV for ~1 hours.
4. Using remote, entered service mode and initialized ( factory reset) the TV
5. For 1 hours of proper run, measured voltages. LED+24v was showing properly at 24v, AL+3.3v was at proper 3.3v and the P-ON-H1 was properly at 3.3v
6. After about 1 hrs, the screen shut down. The LED+24v is showing at 6v, AL+3.3v at 3.3v and P-ON-H1 is a 0v. This indicates the main cpu board has turned off the P-ON-H1 signal.
7. Power off, wait for 2 min. Power on... same philips logo and TV shuts down. Problem repeats.
8. Firmware is Code TVNB010_00_PF_XX91_BA PIC code U10_CM08:_40A_C7W_R_02. Did a google search and found no references if this firmware needs any upgrade.

requesting experts next steps to root cause the issue. I suspect the main board is bad and the SMPS is good. What if I manually put a wire from AL+3.3v to P-ON-H1 ? will the TV be on or is it risky for the main cpu board ?

I am attaching the service manual for this TV