42inch Touch Screen wont power on

[epicfatigue]

Re: 42inch Touch Screen wont power on

Use the standby rail to pull the PSON line to about 5V. The 2.2k-4.7k prevents any damage from potentially excessive voltages (PSON might only want 2-3V), although that would be a very rare possibility I would suggest it anyway.

Get a 1/4W (quarter-watt) 5% resistor of any value from 2.2k (2200) to 4.7k (4700) ohms.

Sorry guys i have been away on business and just got back got the resistor and going to try it tonight.

If the power supply operates correctly which i think it will, how can i go about identifying what this main board is so i can seek a replacement ?

As i have tryed to google to numbers on it and returned no results.

Thanks Guys

[tom66]

Re: 42inch Touch Screen wont power on

Hey i live near a Jaycar so i can get anything electrical they stock just about anything using this to short ?

Use the standby rail to pull the PSON line to about 5V. The 2.2k-4.7k prevents any damage from potentially excessive voltages (PSON might only want 2-3V), although that would be a very rare possibility I would suggest it anyway.

Get a 1/4W (quarter-watt) 5% resistor of any value from 2.2k (2200) to 4.7k (4700) ohms.

[epicfatigue]

Re: 42inch Touch Screen wont power on

Do you have a 2.2k - 4.7k resistor; or can you acquire one (e.g. from RadioShack)?

Hey i live near a Jaycar so i can get anything electrical they stock just about anything using this to short ?

[tom66]

Re: 42inch Touch Screen wont power on

Do you have a 2.2k - 4.7k resistor; or can you acquire one (e.g. from RadioShack)?

[epicfatigue]

Re: 42inch Touch Screen wont power on

ON the main board i followed the power button switch and it has 4.49 volts and drops to 0v when pressed. However on the opposite side where pin10 (on the power supply) connected to the main board we are seeing no 0v drop.

Does this determine there is a fault with the main board? is there a way i can short pin 10 to see if the power supply fires up to indeed confirm this theory?

Would you like pictures of the main board?

[epicfatigue]

Re: 42inch Touch Screen wont power on

Is this IC101 on the board? When talking about components, please always list where it is on the board via pcb identifier so we know where to look. The more info you give, the less we have to guess and ask for clarification.

This is located on the Powersuply IC101 located behind small transformer parallell with the large transformer. inbetween lrage heatsincs.

[epicfatigue]

Re: 42inch Touch Screen wont power on

Sorry guys i did this with the cables pulled out because i thought when the relay clicked it would turn the power off...

i redid all the tests and the volts are slightly diffirent


CN04
1 2.6mv
2 5v
3 0.53v
4 0
5 0
6 0
7 .5v
8 .5v
9 5.24 v
10 4.49v

I tested for volatage drop on pin 10 when pushing on off no change voltage stayed solid.




CN03
1 4.2mv
25.2mv

CN06
1 .5v
2 .5v
3 Blank
4 Blank
5 gnd
6 gnd
7 gnd
8 gnd
9 -.4mv
10 -.4mv
11 -.4mv
12 -.4mv

[retiredcaps]

Re: 42inch Touch Screen wont power on

I pulled the IC off on the small Heatsinc it is DH18 B DM0465R

Is this IC101 on the board? When talking about components, please always list where it is on the board via pcb identifier so we know where to look. The more info you give, the less we have to guess and ask for clarification.

[retiredcaps]

Re: 42inch Touch Screen wont power on

hey mate here is rear trans testing

How is this transformer numbered? Please post a close up picture of the back with its numbering.

[retiredcaps]

Re: 42inch Touch Screen wont power on

CN04
9 5.24 v
10 2.94v

We are still getting 5V SB. Pin 10 is power on/off.

If you hit the power off/on button, see if pin 10 drops to 0.0V. It should change between 0.0V and 2.94V if the main/logic board is working properly.

[epicfatigue]

Re: 42inch Touch Screen wont power on

So, I've been away for a while from this thread...

Bring me up to now:

Have you got any output voltages, at all, on the power supply?

okay guys sorry re tested everything, found some unusal results to say the least.


CN04
1 0
2 -351.7 mv
3 -351.7 mv
4 0
5 0
6 0
7 -349mv
8 -349mv
9 5.24 v
10 2.94v

However with the power off doing a continuity test and touching a common ground pins 1-8 all show as a ground????

CN03
1 4.2mv
25.2mv

CN06
1 7mv
2 4.2mv
3 Blank
4 Blank
5 gnd
6 gnd
7 gnd
8 gnd
9 .4mv
10 .4mv
11 .4mv
12 .4mv

This again is unusal pins 9-12 show as a ground aswell ?

have uploaded pictures let me know where to go from here guys.

[tom66]

Re: 42inch Touch Screen wont power on

So, I've been away for a while from this thread...

Bring me up to now:

Have you got any output voltages, at all, on the power supply?

[epicfatigue]

Re: 42inch Touch Screen wont power on

okay so i re esembled it and tested pin 3 and 2 and i got 14.54 v

#23
test returned 1022m ohms.

is it possible that another board is dead? like the relay wont click if the other boards are not plugged in?

[epicfatigue]

Re: 42inch Touch Screen wont power on

okay so i re esembled it and tested pin 3 and 2 and i got 14.54 v

[epicfatigue]

Re: 42inch Touch Screen wont power on

Hmm, I think from looking at the hot side data and the picture in post #20, I would have expected continuity between more pins in the primary and tertiary.

I'll see if tom66 and PlainBill concur or not. I could be looking at the wrong transformer too.

You might as well test "in circuit" the yellow transformer below the big one. You don't have to desolder, but we would like to see the same "all pins" combination test.

hey mate here is rear trans testing the one infront of bridge rec anyhow while i am waiting for more instructions.

Should i test the mosfets?

[retiredcaps]

Re: 42inch Touch Screen wont power on

Hmm, I think from looking at the hot side data and the picture in post #20, I would have expected continuity between more pins in the primary and tertiary.

I'll see if tom66 and PlainBill concur or not. I could be looking at the wrong transformer too.

You might as well test "in circuit" the yellow transformer below the big one. You don't have to desolder, but we would like to see the same "all pins" combination test.

[epicfatigue]

Re: 42inch Touch Screen wont power on

Still missing a whole bunch of data. See post #89 again for the pattern and compare to your xls file.

sorry mate here we go.

It was very hard to get the reading of resitance it seemed to be very tempermental

[retiredcaps]

Re: 42inch Touch Screen wont power on

Still missing a whole bunch of data. See post #89 again for the pattern and compare to your xls file.

[epicfatigue]

Re: 42inch Touch Screen wont power on

Check your pdf file. The formatting is all screwed up? I can't find 1-2, 1-3, etc.

If you can't get it looking correctly in the pdf, then post your xls file.

sorry didnt see that i am just sitting an waiting lol here is the xml

[epicfatigue]

Re: 42inch Touch Screen wont power on

1) Datasheet is at



This is a FET/SMPS. Refer to figure 3 for the pinouts.

2) Pin 3 is Vcc and pin 2 is GND. Measure the resistance between these 2 pins. Report the reading.

3) According to the datasheet, when Vcc reaches 12 V DC, it starts working. After we tell you to reinstall everything, check Vcc to see if it gets to 12V DC.

4) Page 13 has a schematic.

.480 M ohms between pins