Hanspree HSG1075

[rhodesjo]

Re: Hanspree HSG1075

revised post below

[rhodesjo]

Re: Hanspree HSG1075

Did you by chance mean R47? I can't seem to find 4R7. Also, are my meter tests affected by the fact that my boards aren't screwed into the metal chassis, just sitting on it? Last thing, do I test 4R7/R47 with the power on or off? Thank you guys for everything so far!

[selldoor]

Re: Hanspree HSG1075

First a major rule

When testing voltages power MUST be ON
When testing Resistance (ohms) Power MUST be OFF

He meant 4R7 from the connector go slightly to the right you will see L49 upside down- just above that is the 4R7

I think Tom was also thinking not having it joined up was causing a problem hence

"Also, let's make sure the chassis test is good; I just have a feeling. Set your meter to 200 ohms. Probe from the metal shield of the connector on the main board to the chassis of the TV -- you should see under 3 ohms."

So perhaps do that first. Depending on the result it may then be necessary to wire the board from a ground screw to the chassis.

[rhodesjo]

Re: Hanspree HSG1075

thank you for the description on 4R7, I found it right away after that! ok here are the test results, I see .2- on each side of 4R7, it bounces around slightly, .25, .23, depending on my unsteady hand I'm assuming. As for the ohm test on the chassis, that number is much higher, bouncing around 70+ to 124+, very unsteady. I had the meter set at 200k OHM for the chassis test and 20V DCV for the 4R7 test.

[selldoor]

Re: Hanspree HSG1075

Ok - well not being connected up is a problem.
I dont know how big the set is - can you put the boards back in and still work on it.
Make sure the panel is going onto a dead flat surface - no screws wires- connectors
then put at least one screw to hold each board preferably through a hole with a metal tag.
Then redo the tests and post the results.
Start with that last ohms test as if it is not less than around 3 ohms its not much good doing the others.

[rhodesjo]

Re: Hanspree HSG1075

I did my best to isolate the board from the chassis, with the exception of one screw "grounding the board." In this picture, I am performing the ohm test the way I understood it to be and I was getting 0.00 on my meter.

[selldoor]

Re: Hanspree HSG1075

Haha - I read Toms post where he said for you to use 200 ohms but it didnt sink in that you used 200,000ohms I thought therefore you were getting 70 ohms so yes it is ok at 0.7.

[rhodesjo]

Re: Hanspree HSG1075

oops, I didnt see the plain 200 there, you guys probably think im a lost cause here lol so basically are we trying to determine at what point power is lost before the tcon board?

[selldoor]

Re: Hanspree HSG1075

Yes
On the pic of the connector on the main board on the right hand edge about halfway up is a board mark F9 - is there a fuse there?
Can you do a clear straight on picture of the main board it will help trying to trace why there is no voltage on the connector There looks to be mosfet and voltage regulator
but havent bottomed out what they are - Badcaps.net keeps vanishing and resetting dns only lasts a few minutes.

[tom66]

Re: Hanspree HSG1075

Try using the "200" ohm setting, not "200K".

[rhodesjo]

Re: Hanspree HSG1075

Here is the shot of the main board/connector

-the test with 200 instead of 200k gave me basically the same result - 0.00, keep in mind that I can't put the board back in its mounts or I wouldn't be able to reach the areas for the test. it sits in upside down. Hopefully I've isolated it for the tests properly.

Does a test of 0.00 instead of 3ohm mean that I am not testing it correctly?

[selldoor]

Re: Hanspree HSG1075

Id have thought it was ok - but Tom will know better.
In the meantime that is some weird dual purpose board Can you test F9 or
L77 whatever it is ( Inductor?) as a fuse - power off meter on ohms 200
and also further across to the right f8 which is a white fuse.

As we are on F8/9 perhaps check around the board and check all the F numbered components as fuses.
Ill leave that with you as Im off to bed.

[rhodesjo]

Re: Hanspree HSG1075

each fuse you mentioned gave me roughly .3 on the meter when I set it on 200 ohm and put positive on one side of the fuse, negative on the other side.

[tom66]

Re: Hanspree HSG1075

You need to use 200 ohm range, not 200 kohm.

[rhodesjo]

Re: Hanspree HSG1075

I have been since I realized that, sorry about the confusion earlier

[tom66]

Re: Hanspree HSG1075

OK, zero ohm is OK.

"4R7", or L49, what is the voltage on the end closer to the connector?

[rhodesjo]

Re: Hanspree HSG1075

4R7 = .25 on the connector side. I had the power ON and the meter set to 20V DCV

[tom66]

Re: Hanspree HSG1075

OK, can you check the voltage across C642, it's in the same area.

[rhodesjo]

Re: Hanspree HSG1075

one side of C642 is 12.01-12.15, the other side is 0.00

[tom66]

Re: Hanspree HSG1075

K, so power is getting to that area, but the switch (MOSFET Q2) isn't letting it through, either because it is failed or because it is not being told to turn it on.

On Q2, there is a small dedent. This marks pin #1. Counting from right to left, you will reach the fourth pin. This is the gate. If it is turned off, it will measure around 12V. If it is turned on, it will measure at least 3V less than 12V, quite possibly 0V.