Hyundai ImageQuest L70S+

[820uF]

Hi!
I have this problem with this display "when power cable connected, power button green LED blinking" Nothing happens when button pressed.
All caps look fine.
Transistor secondaries differ under 3%
Big Diodes show:
...with 2k ohm function:
D3. .256 back on cathode side, second way it shows .743
D6. .256 back on cathode side, second way it shows .747

Images from power poard:

[selldoor]

Re: Hyundai ImageQuest L70S+

On the back of the board there is a place marked F3 - is there a fuse on the front of the board to correspond?

With it all connected up and on ,black probe on ground with the red probe test each pin on the connector to the main board. List what you get
along with what it should be (listed on the back of the board.

[820uF]

Re: Hyundai ImageQuest L70S+

F3 fuse is ok. current flows thru - no resistance.

Now about voltages - when video board connected they start jumping -
12V: 11-18V
5V:1,5-4,5V
SLP: 0,00V
MID: 0,7-2,4V

When video board not connected:
12v: 12,24V
5V: 4,98V
SLP: 0,00V
DIM: 2,57V

[selldoor]

Re: Hyundai ImageQuest L70S+

Do the backlights flash at all
Can you check the voltage on each side of that fuse.
Black lead on ground then red probe on each side of fuse

Please post clear pictures front and back of the main (Video) board

[tom66]

Re: Hyundai ImageQuest L70S+

I'd replace the startup cap if voltages are jumping.

[820uF]

Re: Hyundai ImageQuest L70S+

actually the display powers on after some time led blinking

[selldoor]

Re: Hyundai ImageQuest L70S+

The startup cap is probably the one next to U2

After the set has cooled down switch it on again and try heating that cap with a hairdryer to see if the set comes on quicker

[820uF]

Re: Hyundai ImageQuest L70S+

I'd replace the startup cap if voltages are jumping.

replaced this cap (47uF 50V) with same parameter cap and still same blinking.

[820uF]

Re: Hyundai ImageQuest L70S+

Do the backlights flash at all
Can you check the voltage on each side of that fuse.
Black lead on ground then red probe on each side of fuse

Please post clear pictures front and back of the main (Video) board

both sides 16,12V it droped about 2minutes from 16,4V - same voltage as 12v pin has.

pics of mainboard:

[selldoor]

Re: Hyundai ImageQuest L70S+

Was that with all boards connected?

On the main board there are two voltage regulators can you test them.
( Haha Up to the same point as in your other thread)

[820uF]

Re: Hyundai ImageQuest L70S+

U1

pin 1 = 0,01
pin 2 = 2,50
pin 3 = 4,40



U3

pin 1 = 0,01
pin 2 = 3,30
pin 3 = 4,40

[budm]

Re: Hyundai ImageQuest L70S+

U1 (2.5V REG), U2 (3.3V REG)
They are OK.

Can you take the resistance reading on the IC2 (Vref Diode, ?? 431)) on the power supply board. Take the reading like this:
Pin 1 & 2
Pin 1 & 3
Pin 2 & 3

[820uF]

Re: Hyundai ImageQuest L70S+

on 20k function
IC2
Pin 1 & 2 - 9,93
Pin 1 & 3 - 3,7
Pin 2 & 3 - 13,64

[tom66]

Re: Hyundai ImageQuest L70S+

It's IC1 in this case that's the Vref.

[820uF]

Re: Hyundai ImageQuest L70S+

on 20k function
IC1
Pin 1 & 2 - 1,02
Pin 1 & 3 - 4,09
Pin 2 & 3 - 3,71

[budm]

Re: Hyundai ImageQuest L70S+

Sorry, that will be IC1.You have to test it off the board. I have them here also.
Flat side toward you, legs down.
The readings on all 3 leags combination usinh Ohm meter should be in the Mega Ohms (to over range) range (does not matter how you use red/black probes)

[820uF]

Re: Hyundai ImageQuest L70S+

IC1 offboard
on 2M
Pin 1 & 2 - first it showed jumping numbers around 1.400, now it shows nothing
Pin 1 & 3 - nothing
Pin 2 & 3 - nothing

IC1 offboard
on 2k
Pin 1 & 2 - like runs out of scale
Pin 1 & 3 - 1.207
Pin 2 & 3 - .913

IC1 offboard
on 20k
Pin 1 & 2 - like runs out of scale
Pin 1 & 3 - nothing
Pin 2 & 3 - nothing

IC1 offboard
on 200k
Pin 1 & 2 - like runs out of scale
Pin 1 & 3 - nothing
Pin 2 & 3 - nothing

[820uF]

Re: Hyundai ImageQuest L70S+

is "TL431CLP 2.5-36V 100mA" suitable replacement for this "UTC TL431 SAF" ?

[820uF]

Re: Hyundai ImageQuest L70S+

replaced this TL431CLP and same

[selldoor]

Re: Hyundai ImageQuest L70S+

Ok - try a hairdryer on different parts of the board to see if it comes on any quicker