Philips 42HFL5581V/27 No Power

[neilc6]

Looks like the "H" in the model number indicates this is a hospitality (hotel) TV. Sticker part #272217100802. Just found service manual searching the chassis PB52.2HU LA

Main fuse is ok and all electrolytic caps not bulged

CN4
-Vaudio: 0
GND: 0
+Vaudio:0
+12: 0
GND: 0
STBY: 2.58 (low??)
3V3 STBY: 3.39V

CN5
PWM: 0
BOOST: 0
DIM: 0
BL_ON: 0
GND: 0
+12.3V: 0

Since it's a hotel TV, they are pretty much locked down (you typically can't change the source input) and you need a master remote to reconfigure the TV. Not sure if it's even worth the effort to repair.

Need to go through the service manual.....

[budm]

Re: Philips 42HFL5581V/27 No Power

"STBY: 2.58 (low??)" That is the same function as PS-ON, and in this case, <1V = ON, >2V = OFF.
Right now you have 3.3V standby Voltage to run the main board but the main board is not pulling the STBY pin low (Active LOW) to turn on the rest of the power supplies, and it also not pulling up the BL-ON high (Active high) to turn on the backlights circuit, it also dies not send the Dimming control signal.

[neilc6]

Re: Philips 42HFL5581V/27 No Power

I measured the voltages with the connectors disconnected not realizing STBY was the PWR_ON signal. Thought it was a 5V standby since the front LED isn't lit.

Remeasuring, I get 3.33V on STBY but only 0.58V on the +12V outputs on both connectors. If it is active low, I guess I could force the PS on to confirm it is ok. I'll re-check the service manual.

Edit add: Ok, I'm not very observant.

When the TV is first plugged in, there is +12V out, 397V on main cap and STBY goes low so the PS is turning on. There is some voltage on the DIM signal. After a couple of seconds, I hear a "clunk" from the speakers and the TV shuts off completely. Front LED completely off and no response to the power button during this time as well. BL_ON is 0 through this entire sequence which is expected I guess.

[budm]

Re: Philips 42HFL5581V/27 No Power

You have to look at the main board at this point.