Hisense LCD37V88P not powering

[s_henya]

Hi guys,

Got this set, with not powering issue.

I have a red light on the front panel (maybe standby) on and on the touch buttons.

I have 24vdc on the inverter - but with no backlight.

on touching the touch buttons i can hear beeps.

i got 409vdc on main filter cap.

on touching the power button i can't seem to power it off/ on i have steady 24vdc on the inverter.

tried the flashlight trick but got nothing.

i want to force start the psu and the inverter alone to isolate logic card fault.

need your help with this one, the connector legend isn't clear.

[budm]

Re: Hisense LCD37V88P not powering

The power supply is woprking and it is getting the PS-ON to turn on the PFC Voltage booster circuit to produce the 409VDC on the main cap and the 24VDC for the Inverter board.
For the backlights to be on you have to have the BL-ON (>2.5VDC = ON, >1VDC = OFF), and the DIM control signal.
If you do have the control signals but still no backlights then you have ineverter board problem. So look at the labels on the inverter board connector to find those required signals.
I can see the ON/OFF (BL-ON) pin 12 but I cannot read the rest of the labels, pictures are way too out of focus.
The fuse on the inverter board is OK, right?
https://www.badcaps.net/forum/attach...5&d=1437243126

[s_henya]

Re: Hisense LCD37V88P not powering

Thanks for replying budm,

how do you suggest turning on the backlights?

and what in your opinion the reason for not being able to turning the tv on/off?

what voltages should i get on the connector on the inverter from the psu?

(im not sure its lcd, maybe led) only 2 transformers and anly 2 wires to the backlight.

(and YES the fuse is good- it was the first thing i checked :-) )

[budm]

Re: Hisense LCD37V88P not powering

"and what in your opinion the reason for not being able to turning the tv on/off?" That is the indcation of the main board problem and may be that is why it is not sending the ON/OF signal to the inverter board ON/OFF pin that you need to check.

"what voltages should i get on the connector on the inverter from the psu?"
Reply on post #2 "If you do have the control signals but still no backlights then you have ineverter board problem. So look at the labels on the inverter board connector to find those required signals.
I can see the ON/OFF (BL-ON) pin 12 but I cannot read the rest of the labels, pictures are way too out of focus.
The fuse on the inverter board is OK, right?"
So check the DCV on that ON/OFF pin when TV is turned on.
Your TV uses CCFL not LEDs for backlights. the LCD panle lookS to be made by LG, you can see LG printed on the inverter board.

[s_henya]

Re: Hisense LCD37V88P not powering

ON CN1 (inverter board):
PINS 1-5 : 24.79VDC (VIN)
PINS 6-10: 0VDC (GND)
PI 11: 0VDC (NC)
PIN 12: 0.07VDC (ON/OFF)
PIN 13: 0.037VDC (VBR_B) (maybe brightness?)
PIN 14: 0.004VDC (STATUS)

this means that the logic board isn't sending the on signal to the inverter right?

could i simulate this signal by 1k resistor to GND OR 5V?

i don't know if its active on LOW or HIGH.

[s_henya]

Re: Hisense LCD37V88P not powering

what do you think?

[CapLeaker]

Re: Hisense LCD37V88P not powering

Your BLon signal isn't there.

[s_henya]

Re: Hisense LCD37V88P not powering

so this means i have a bad mainboard?

what do think, this one might suit? RSAG7.820.1621 (the original was RSAG7.820.1856)

http://www.ebay.com/itm/Hisense-Sign.../221829433473?

[CapLeaker]

Re: Hisense LCD37V88P not powering

make double sure that the BLon signal is not getting sent at the main board, before do anything. As far as the other main board goes, make sure it is compatible to the original one. It doesn't have to be the exact same, but it has to be compatible. I am not sure if that board on ebay is compatible or not. You would have to figure out in what TV that board was in.

[s_henya]

Re: Hisense LCD37V88P not powering

just ordered a mainboard from http://world.taobao.com/item/4262474...?fromSite=main

hope it will solve the problem.

I will update as soon as i will get it.

[s_henya]

Re: Hisense LCD37V88P not powering

Some progress:

I got the mainboard from china, got a little mad for being fooled by the Taobao agent:

'Taobeo Focus'- don't buy from him. he overweight your package so the shipping fee would be much higher.

this mainboard weighs 350grams. and the whole package weighs 1.15kg.

800gr of cardbox in cardbox in cardbox. instead of 5-10$ for delivery i payed 35$ for delivery only!

Back to the Tv:

now i can get it to power. the thing is that this mainboard was designed to work on a 42" instaed of 37". the control panel (touch buttons connector is 3 pins instead of 4)
i replaced the connector but still no luck. i can see that in my failed board i have an extra resistor which doesn't exist on my new board. i will try to transfer it carefully as it is very small.

i dont have the original remote. so maybe buying a universal remote would do.
any help on that too would be great!

[CapLeaker]

Re: Hisense LCD37V88P not powering

Some main boards allow you change the screen size (37 vs 42") but that has to be done in service mode of the main board.

[s_henya]

Re: Hisense LCD37V88P not powering

I took the resistor from the failed board, showed almost 0 ohms.
So i just replaced it with a short. i have lights on the touch buttons and i can hear beeps upon touching. but only the power button gives something->opens the menu. :-(

i tried setting the cable company remote to work on the TV, it semi works,
by pressing the numbers i can power, and visit the menu. and source as well.

i have a perfect picture on hdmi1 but no sound. i can't set the volume scale.

i have to get a remote for this tv. anyone knows a good universal remote for Hisense?

[CapLeaker]

Re: Hisense LCD37V88P not powering

Acoustic Research, Logitech... those can learn codes too

[s_henya]

Re: Hisense LCD37V88P not powering

I tried another remote,

now i can power, source, vol +-

I still got a perfect picture but no sound (tried SCART & HDMI).

maybe i recieved a faulty mainboard.

i can transfer parts from the old mainboard, but i never fixed a 'no sound issue' before

[CapLeaker]

Re: Hisense LCD37V88P not powering

Do you get any sound at all? Try the TV channels. If not, check if the sound IC is getting proper voltage or for shorts?

[s_henya]

Re: Hisense LCD37V88P not powering

No sound at all.

i found one smd cap broken missing on the back of the board, trasfered it from the faulty board but still no luck.

cant seem to find the audio ic. maybe it's behind the metal bezel

[CapLeaker]

Re: Hisense LCD37V88P not powering

must be underneath that metal shield that's where the traces go anyway.