Phillips 32PFL4507/F7 screaming power board

[CapLeaker]

Re: Phillips 32PFL4507/F7 screaming power board

Maybe upload the service manual?

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

It's in my second post attachments. I'll attach it again

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Checking the cable going to the function board I do get AL+3.3V in but no p-on+5V.

The voltage off the regulators is all lower than it should be - I'm think because the power supply can't provide a solid 21V? I can't get the TV to turn on. The LED does work when I power it with my DMM :p but nothing past that.

I'm kinda losing faith here :c

[budm]

Re: Phillips 32PFL4507/F7 screaming power board

I think I found something!

I removed all three voltage regs on the MB and it was still shorted. Then I randomly removed C3103 by the 1.2V reg and the short went away. Up to ~10Mohms on the p-on+21v rail.

But, I left C3103 off the board. Does it do anything critical? It's near the 1.2V reg on page 51 of the service manual. If it's just a filter or something can I survive without it? .

Secondary problem: the TV still will not turn on. From the schematic it doesn't look like it has a standby LED - just a power on white LED with no dual mode or anything. Pressing the power button or the remote gets nothing. The whine is a lot quieter now even with everything (LCD + BL) plugged in.

When it's plugged in and sitting p-on+21v is still at 7.82 and amp+24v sits at 9.8v while al+3.3 is at 3.3v

Thoughts?

What does the cap look like? Light tan color with rectangular shape? It needs to have the cap in place otherwise the regulator may go into oscillation or unstable Voltage may occur.
Those low Voltages are normal at standby mode, it will kick up to normal level when the main board sends out the P-ON-H2 signal (>2.5VDC)to turn on the power supply into full mode.

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Yeah, it's a little SMC - small, rectangular, and tan. The schematic just says 4.7 uF with no other info about it. It has no markings I can see.

It seems the board won't send P-ON-H2 -- either it can't get the instruction to turn on or it's deciding not to. Since it seems the function board is getting the 3.3V I don't think that's an issue. Something logical not working perhaps?

Could I just connect the al-3.3v to the p-on-H2 pin and force it on? Would that be a terrible idea? Not a permanent solution obviously but if I could get the panel on and could see if the LCD/backlight/PSU worked I would buy a new main board in a heartbeat. I just don't want to risk it.

[budm]

Re: Phillips 32PFL4507/F7 screaming power board

The MLC cap tends to fail in shorted out mode.
You can force on the P-ON-H2 high using the resistor (anything between 330 ~1000 Ohms will be fine) but you have to disconnect that P-ON-H2 line from going back to the main board first otherwise the main board will keep that line so and not allowing it to go high.
You can run the power supply board by itself by using 3 resistors between 3.3V and P-ON-H2, BL-SW, BL-DIM to test the power supply function.

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Ok, I replaced the cap with an "identical" one from the bad power supply. Maybe a bad assumption but it'll have to do for now.

I lifted the pin for the H2 and put a 10k (all I have) resistor between it and 3.3 - now my +21v is 21V and the amp+24 is 24.5 .... so that's good I think! PSU seems to work!

The tv still won't turn on though. No power LED, no backlight on. I don't know if it's a power issue somewhere deep in the main board or a logic issue with one of the chips. What do you think?

At this point I think I'm going to just buy a new MB and function board. It's a risk but I'm convinced the power supply is ok enough to be ok. I guess my only worry now is that the panel is dead or the backlight is burned out. Any suggestions on ways to test that before throwing more money at it?

Would you risk it? Is it common for bad backlights/LCDs to just take everything else with them?

[Diah]

Re: Phillips 32PFL4507/F7 screaming power board

PWB now we are sure it work, and the main board don't sends out the P-ON-H2.
before you go to buy MB you can go to play round , i suggest you the big chips (which responsible on this signal ) on MB heat it very well with hot air gun, but be sure it remain at its place while you heating it. leave it cool down then put every things connected and try now to turn the TV on.

[CapLeaker]

Re: Phillips 32PFL4507/F7 screaming power board

Also freeze the EEPROM chip (an of air upside down), heat or freeze the main IC and see if something changes.

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Reflow and freeze didn't change anything.

I checked the regulators:
The 1.2v line is only .53v -- that I think that could be a problem since it directly powers the main chip. I've checked every part and I can't find any reason it would be lower. All of the resistors and everything measure fine. I'm thinking maybe I cooked something while troublshooting/reflowing/freezing.

New regulators are $20 from china. I'm just going to risk the $60 to get a new board. I'll report back if anything works. Or if nothing else a photo of a messed up LCD module

Y'all are amazing. Thanks for the help so far! I've learned a lot

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Ok, so I put in the new board and the TV turns on! Exciting! I can use it and everything.

Major problem though - the image is totally reversed. In service mode it should be red green and blue but is instead magenta, yellowish, cyan. White and black work fine.

Tried resetting it from the service menu (no luck). Left it unplugged for a bit. Tried different inputs. It's always a reversed image. As far as I can tell there is no firmware upgrade available -- it's running TVNB011_00_PF_XX91_AA

Thoughts?

[CapLeaker]

Re: Phillips 32PFL4507/F7 screaming power board

so your image is backwards and the colors are off?

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Just the colors were reversed. Image was fine.

Doesn't matter though. The power board made the overload noise again and now it won't display anything. Back light turns on. It responds to the remote. But there is no image.

There was an image. It was working (minus the colors). But now nothing.

I assume something is wrong with the TCON board but it's one of those soldered-to-the-LCD deals so I don't think that's fixable. Despite all the effort and money I think this thing might be dead for real now.

[CapLeaker]

Re: Phillips 32PFL4507/F7 screaming power board

Oh well... one can't fix everything. Did you check the fuse on the Tcon?

[Diah]

Re: Phillips 32PFL4507/F7 screaming power board

you need just put yours panel code at the new board via service menu

[ReeceyBurger123]

Re: Phillips 32PFL4507/F7 screaming power board

Diah is correct the motherboard is not set for the panel, should be fixable.

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Yeah, but now it has no display at all. I feel really stupid lol.

So close and I fried it.

There doesn't seem to be a fuse or anything on the tcon. The cable is good. I think I may have either fried the motherboard again or the tcon (is it even called a tcon here?) so I just don't know. I tried replacing the eeprom but no luck there either.

Any thoughts on things to try or am I SOL here?

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

To be clear:

It was working and in service mode. I touched it and the cable going to the LCD slipped and shorted something (PSU got loud) I panicked and just cut the power.

Now it turns on, but it doesn't display anything. Backlight comes on, responds to remote (turns on and off) and everything. I'm trying to figure out now if it'll connect to something HDMI so I can see if it's actually trying.

So I broke an otherwise easy fix after all this time doing something stupid...

[pyrohmstr]

Re: Phillips 32PFL4507/F7 screaming power board

Put the eeprom from the old mobo on the new one. It turns on but still no picture.

[Diah]

Re: Phillips 32PFL4507/F7 screaming power board

do you have close clear photo on yours T-CON. suggest you don't play any more at yours MB

i am not sure if this will working on yours model .. but give it try too ...Changing the display option via a standard RC: Key in the code “062598” directly followed by the “MENU” (or "HOME") button and “XXX” (where XXX is the 3 digit decimal display code as mentioned on the sticker in the set). Make sure to key in all three digits, also the leading zero’s. If the above action is successful, the front LED will go out as an indication that the RC sequence was correct. After the display option is changed