Hanspree HSG1075

[rhodesjo]

brothers, what you see in the picture is a dismantled hanspree hsg1075 28inch lcd monitor. As you can see I have removed all covers on the back. This monitor only displays white when powered on, sound works perfectly fine. No splash logo displays, just bright white. Any direction on which board is bad and needs replaced? Somewhat proficient PC tech here (not TV). No apparent damage to any boards, no loose connections.

[Pentium4]

Re: Hanspree HSG1075

It could have just been a loose ribbon cable going from the main board to the panel. Did you try re-seating it to see if it gets a picture?

[rhodesjo]

Re: Hanspree HSG1075

I can remove the black tape covering the ribbon cable connectors and try that, I haven't yet. Thank you, I'll post again once I test that!

[rhodesjo]

Re: Hanspree HSG1075

Ok, I removed the black tape that was covering the ribbon cable connectors between the large green board with video inputs and the small green board (tcon I believe), unfortunately after re-connecting the ribbon cable the white screen still occurs.

[selldoor]

Re: Hanspree HSG1075

At the bottom of the [picture there is a metal plate over the Tcon.
Can you post a really clear picture of the Tcon board.

[rhodesjo]

Re: Hanspree HSG1075

i hope this is what you mean. There is a thin plastic shield over the board that I didn't tear off, I can, if you can't see the board clear enough.

[tom66]

Re: Hanspree HSG1075

Yes, that is the T-con board.

There is a device marked "M" and nearby "F100". This is the fuse. Measure the voltage on both ends of the device, relative to the chassis.

[rhodesjo]

Re: Hanspree HSG1075

Just want to ask really quick, since I'm not as savy with TV's you mean using the voltage meter, positive on one side of the fuse, negative on the other? while the TV is unplugged correct? I don't want to get zapped

[budm]

Re: Hanspree HSG1075

You need to check the voltage on the fuse with the TV POWER ON (hit the power switch), black on the metal chassis, red probe on each end of the fuse at a time.

[rhodesjo]

Re: Hanspree HSG1075

the search for the voltage meter continues, I have not abandoned the cause!

[rhodesjo]

Re: Hanspree HSG1075

Voltage meter FOUND!
So, one final noob question, on this radioshack special voltage meter, (see attached) which setting is appropriate for this very tiny fuse? I am pretty cautious, maybe overly so with electricity I don't understand lol

[tom66]

Re: Hanspree HSG1075

DCV 20V.

You are measuring the low voltage side. Shocks are not possible at the low voltages the t-con and video processor uses. The highest voltage on the t-con is 30V DC. The SELV level (safety extra-low voltage) specification is 60V DC. I have a 35V DC power supply. I can touch the output (and regularly do) with sweaty or dry hands and am not electrocuted yet.

However, do not touch any of the heatsinks (metal plates) on the power supply, as they can easily give a very nasty shock.

[rhodesjo]

Re: Hanspree HSG1075

with the negative tester on the metal chassis, and touching the red tester to each side of the fuse marked F100 (M) I saw no change on my voltage meter. 0.00 each and every time

[tom66]

Re: Hanspree HSG1075

OK, just to be sure, can you find a fresh 1.5V battery and test that? It should show around 1.55~1.6V if good. Just to check if meter is OK.

[rhodesjo]

Re: Hanspree HSG1075

update: my mistake, tv was plugged in NOT ON, now with the TV powered ON, i do see slight number changes on each side of the fuse, very slight, and still sometimes zero

[rhodesjo]

Re: Hanspree HSG1075

battery test yielded 1.47 on the meter

[tom66]

Re: Hanspree HSG1075

OK, must be slightly discharged but that is fine.
So some how power is not getting to the T-con.

Can we have a closer image around the connector which goes to the T-con but on the main board side?

[rhodesjo]

Re: Hanspree HSG1075

here is the tcon connection on the "big board" side

[rhodesjo]

Re: Hanspree HSG1075

In the picture it looks like the connector isn't plugged in all the way, that just happened when I pulled the tape, I pushed it back in and retested just to be sure. Still 0.00 mainly on the fuse

[tom66]

Re: Hanspree HSG1075

In this picture,
https://www.badcaps.net/forum/attach...0&d=1356560428

Do you see the grey device marked 4R7?

Can you test the output voltage here relative to the chassis of the TV?

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.