Sanyo FW65D25T has backlight but no picture

[cb1175]

I've got a Sanyo FW65D25T and need some help fixing it.

I plug the TV in and the red standby light comes on. I then press the power button on the remote and the standby light blinks red 8 times. On the 5th blink, the backlights come on but I don't see any picture or menu on the screen.

I thought the power supply might have been bad so I replaced it and it didn't make a difference. Can anyone please guide me on what to check/test/replace next? Thinking it is either the tcon board or the main board. Tcon boards are cheap ($27), main boards are not ($295). Would replacing the EEPROM ($15) on the main board possibly help this issue?

[CapLeaker]

Re: Sanyo FW65D25T has backlight but no picture

Check if the T-con gets power to the fuse(s). Other than that, it could be also a symptom of a bad EEPROM. If you got a oscilloscope handy, you can check the LVDS on the main board with it. Flick the menu on and off all the time and look at the differential pairs and see if something changes on the scope.

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

15 vs 295, the eeprom is worth a shot.

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

Should probably test the t-con, see if you can find the procedure, there may be test points marked on t-con.

[budm]

Re: Sanyo FW65D25T has backlight but no picture

Check if the T-con gets power to the fuse(s). Other than that, it could be also a symptom of a bad EEPROM. If you got a oscilloscope handy, you can check the LVDS on the main board with it. Flick the menu on and off all the time and look at the differential pairs and see if something changes on the scope.

Yep, at least find out if T-con circuit is getting power to run or not, or if the the fuse is OK.
We do need pictures to us how all the boards are connected together.
If the T-CON fuse is OK and you are getting 12VDC feeding it then you can try having ribbon cable between the LCD panel and the T-CON board connected one at a time to see what you will get on the screen.
https://www.shopjimmy.com/catalogsea...Sanyo+FW65D25T

EEPROM: https://www.shopjimmy.com/sanyo-fw65...eprom-only.htm

IMPORTANT:
These main boards can have multiple failures, in addition to the EEPROM.
If EEPROM replacement does not repair your board, there are likely additional problems.

Symptoms EEPROM replacement MAY fix:
- On screen display is stuck on logo screen
- TV won't power on with remote or buttons (LED indicator remains same color)
- TV won't turn on after being off for 30+ minutes
- TV shuts off by itself during channel scan or when switching inputs
- TV turns on and is stuck in color test pattern mode forever
- TV turns on but there is no backlight (LED indicator shows TV is on but there is no image)

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

Thanks for the replies.

I'm going to need some help figuring out out to test if the T-con board is getting voltage. I don't see anything marked on the board for test points or voltage specs. I did get some voltages on the pins of the cables connected to the board so I am getting "some" voltage but have no idea if it is correct or not. I don't have an oscilloscope so that is not an option for testing. I'll include a picture of the whole TV to show board layout and a close-up of each board.

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

Locate the tcon fuse, it will be marked starting with F on the board, test for voltage, black lead to a ground, red lead on each side of fuse, usually get 12 volts on each side when things are working right. Your fuse is labeled FP1, its white close to your connector.

[budm]

Re: Sanyo FW65D25T has backlight but no picture

Thanks for the replies.

I'm going to need some help figuring out out to test if the T-con board is getting voltage. I don't see anything marked on the board for test points or voltage specs. I did get some voltages on the pins of the cables connected to the board so I am getting "some" voltage but have no idea if it is correct or not. I don't have an oscilloscope so that is not an option for testing. I'll include a picture of the whole TV to show board layout and a close-up of each board.

FP1 is the fuse. then are lots of Voltage test points: V1N12, V33V, V25V, etc. You just have to look.

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

Thanks for the clarification on where to measure voltage at. Looks like I have power to the T-con board and the fuse is good.

Here's what I've got:
12V in and out of the fuse FP1

Taking measurements at some of the other test points that I saw:
V1N12: 12V
V33V: 3.3V
C_VIN: 12V
VDDAM_R: 9.1V
VDDAM: 9.1V
V12A: 1.2V
V25V: 2.5V

Let me know if you want measurements from any that I missed.

[budm]

Re: Sanyo FW65D25T has backlight but no picture

Try having flat ribbon cables between the LCD panel and the T-con board connected one at a time to see what happen, be careful to seat the cables back in place properly.

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

1. I disconnected both T-con ribbon cables and it acted the same as when both are connected. Backlights come on but no picture.

(Left Side / Right Side below are all from the front of the TV as if you were viewing it)

2. I disconnected the right side T-con ribbon cable and turned the TV on. The right half of the screen was completely white and the left half of the screen was black.

3. I plugged the right side back in and disconnected the left side cable and turned it on. The left half of the screen was completely white and the right half of the screen was black.

Think the T-con board is bad?

Incidentally, there is a used but tested main board that just showed up on Ebay today for $99 if you are thinking the main board might be bad. The only other main board I could find prior to this was a new one at $295 which is way more than I'd want to spend.

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

Anyone have any ideas?

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

Your call, think I would try the eeprom replace but there's no guarantees, like it says might be additional problems on board or may be something else wrong.

[CapLeaker]

Re: Sanyo FW65D25T has backlight but no picture

The lack of an oscilloscope on your end limits testing. I can't tell like that if the main board is actually putting video out on the LVDS cable that goes to the TCON. So in this case I'd go for the TCON first, because it is cheaper, followed by a replacement main board, when the TCON didn't do the trick.

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

Good pic. of the tcon, currently sold out. https://www.shopjimmy.com/sanyo-4z-h...-con-board.htm

[budwich]

Re: Sanyo FW65D25T has backlight but no picture

what are you signal / source are you feeding into the set during your testing (when you did the cable disconnection tests)?

OP, looking at the tcon picture that you posted... what's happened in the area in the middle of the board just above the large chip. There seems to be some sort of "smudge" as the printing / tracks are not clear.

[nomoresonys]

Re: Sanyo FW65D25T has backlight but no picture

Good pic. of the tcon, currently sold out. https://www.shopjimmy.com/sanyo-4z-h...-con-board.htm

Disregard this, looks similar but the sticker numbers don't seem to match.

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

I went ahead and purchased a T-con board. However, the new T-con made no difference - still have backlights but no display.

Answering one of the questions above, I do not have any inputs connected during testing - just trying to get an OSD at this point. Should I have something connected to the inputs instead of trying to see an OSD?

I just ordered a main board from Ebay so will try that next.

[CapLeaker]

Re: Sanyo FW65D25T has backlight but no picture

must be a bad main board then. You don't need to have any source on the inputs connected for the OSD or menu to come up.

[cb1175]

Re: Sanyo FW65D25T has backlight but no picture

I replaced the main board tonight with one that I ordered from Ebay (supposedly fully tested from a repair shop) and still get backlight no picture - same thing it's always done. I did notice the standby light blinks 9 times now instead of 8 when turning it on. Does anyone know what the blink codes on a Sanyo mean?

I still had the replacement T-con board that I bought and swapped that in but didn't make a difference.

The only board I haven't replaced yet is the FRC board. I can't find one for sale right now used or new for this TV. However, in searching for one, I saw that a RCA RLED6090 FRC board looks identical to my board but has a different part number on the board. Should I bother to try replacing the FRC board? If yes, is there any way the RCA one would work or do I need one specific to this TV?

It appears to me that there is an EEPROM on the FRC board and one on the main board. Are they both EEPROM's or is the one on the FRC board something else?