Funai 32FL553P/10 - squealing from PSU, dies after 10 seconds, blank screen after logo, bootloops

[kotel studios]

Hi,

Found an Funai 32FL553P/10 TV on sale for cheap listed as broken, so I decided to give a shot at reparing this.

State I got it in:
Squealing from the PSU
After logo I get a blank screen
After 10 seconds of having a blank display w/ backlight the TV dies
Give it 7-10ish seconds again and it starts to bootloop.

What I did so far:
Replaced all the caps on the PSU (apart from primaries, they were fine and none at hand)
Checked all voltage rails:
5VSB - 4.8V
AMP+13V - 14.4V
13V - 12.98V (in manual 12V)
PS_ON - 4.8V (always high)
BL-ADJ - 4.98V when TV in STBY, 4.78V when ON
BL-SW - 0.03V when in STBY, 5V when ON
LED1 - 2.38V
LED2 - 2.36V
VLED - couldn't get a reading

The 470uF 25V caps C403,402,407 had been replaced for testing with 860uF 25V (I was out of 470uF caps)


Now this makes me suspect two things:
Squealing: the AMP+13V rail being out of whack, although the noise seems to come from the transformer (which can be heard even with the TV fully assembled and being like 2-3 feet away).
Bootlooping cause: bad FW, main PCB seeing that AMP+13V is out of whack so it cuts the power (unlikely since the TV turns on after some time on it's own), or both.

Read on a forum post that swapping the FW fixed this (squealing was caused by the PSU being unloaded).

Any ideas?

[lotas]

Post your original dump (firmware) here, I'll look at it and fix it if anything.

[kotel studios]

Dumped.
Mainboard is MSD309.B95

Oddly, comparing it to a dump from a working TV I found online (same model and PCB) it's waaay different. Maybe different revision or something like that.
The one from internet is the file starting with "FUNAI_model..."

[lotas]

Dumped.
Mainboard is MSD309.B95

Oddly, comparing it to a dump from a working TV I found online (same model and PCB) it's waaay different. Maybe different revision or something like that.
The one from internet is the file starting with "FUNAI_model..."

Your dump is very badly damaged, I fixed it, try it (or better yet, write it to a new SPI flash drive)

[kotel studios]

Okay, it seems to work. Thank you!
Now what can we do about the loud squealing from the PSU? When it's loaded it is quieter (sounds as a normal 2008 TV under normal operation).

[nomoresonys]

Check the capacitors you replaced over, make sure they're getting good solder contact. I use the multimeter, a probe on each leg to make sure none of them are reading low ohms. Sometimes a new cap can be bad, good policy to check before installing if possible.