Hanns-G HH191/HSG1070

[Rusty!]

Hi guys, I have picked up the above monitor (it has two model numbers so I thought I'd list both) for nowt because it suffers from the "two seconds to black" phenomenon. Flicking the power off/on will bring the picture back for a couple of seconds, then it's gone etc.

Would be a shame to scrap it as I'm sure it can be fixed, however my initial investigations (as instructed by the sticky thread) have drawn a blank (this is quite possibly due to me being an idiot).

The caps on the board are mostly Su'scon, with a couple of Samxon and one huge Elite thrown in for good measure, none of which are visibly failing. When checked with a multimeter resistance increases as they charge, but the rate of charge varies, I'm putting that down to different levels of capacitance, but as mentioned above, I'm an idiot so this could be wrong.

I've attached two huge pictures of the board in the hope that someone can spot something I haven't

[selldoor]

Re: Hanns-G HH191/HSG1070

Welcome to the forum
Excellent pictures - why can't they all be like that.

The sticky you read was it the 2 sec to black? guide. If you have to refer to it
the latest rewrite starts at post19.

In there it mentions testing secondary winding on the inverter transformers.
On the back of the board these are labelled T1 and T2
Power off for 5 minutes can you set your meter on 2000 ohms and test across
the two connectors on the transformers- that is at the end with only two connectors and post the results.

Have you any spare ccfls bulbs or another monitor of any size that you can
open up?

PS all the caps you mention are considered poor.

[Rusty!]

Re: Hanns-G HH191/HSG1070

Heh thanks, mobile phone cameras aren't all bad... yay for HTC I guess.

As for the transformers, I get 450Ω for T1 and 461Ω for T2

I don't have a spare CCFL kicking about, but I'm pretty sure I know where a screen I can butcher is (it's smashed though, but the backlight still works). I had a feeling all that caps would be pants, it's not like Hannspree are known for being super high quality!

[selldoor]

Re: Hanns-G HH191/HSG1070

As for the transformers, I get 450Ω for T1 and 461Ω for T2

I don't have a spare CCFL kicking about, but I'm pretty sure I know where a screen I can butcher is (it's smashed though, but the backlight still works). I had a feeling all that caps would be pants, it's not like Hannspree are known for being super high quality!

Transformers look good - caps may be a problem - if you get it working you may consider replacing anyway. However for your initial description most voltages seem ok and the transformer test is easy.

Next easy test is with it all connected up ( But see last line) can you
check the low voltages. Meter on 200 VDC black probe on a ground screw or tab check down the connectors with the red probe and post the results.
CN1
Pin 1 18v actual 17.92v
Pin 2 12v actual 12.02v etc etc.

Take care as although these are low the HOT side of the board is at 240v
or even 400v in places.

Next is if you can salvage a good lamp or even better two, you can just
substitute them for the ones that are in to see if it is the bulbs/wiring at fault.
If you can get at the panel easily you may be able to see if the ends of the bulbs are blackened or if there is a wire off.

Can you of pictures of the other boards.

[Rusty!]

Re: Hanns-G HH191/HSG1070

Pics of the other board is no problem (there is only one), so I've attached them.

Getting readings of CN1 is proving to be a right bastard, though. It is completely unstable, to get anything other than 0.00 I have to keep switching the monitor on and off, and even then the reading I do get lasts about a second.

This seems to correspond with the time that the screen will stay lit for, so I am gonna put my neck on the line and say that the panel/CCFL is not the culprit here?

Also, despite your warning, I managed to shock myself off the top of one of the caps on the top left of the board (I think, it was something in that area) Oh well, not the first time, and I'm sure it wont be the last.

[selldoor]

Re: Hanns-G HH191/HSG1070

Have to change your name to sparky! then. Rubber gloves and wellies from now on.
Forget the voltage measurements for now. Despite your theory I think it may be the bulbs. As I understand it you switch it on and video board does various internal self tests
then tells the power supply to power up. Does various internal tests and sends a signal to switch on the ccfls - I think they come on last. If they dont all light or there is a problem with the wiring it trips a safety which turns almost everything off.

[Rusty!]

Re: Hanns-G HH191/HSG1070

Dang, it was also sounding so simple for a second

I'll have access to the butcher-able panel on Wednesday when I'm back in work, so hopefully something more will come to light when I have something to swap out.

Thanks for all the help and info, this place is great!

[DMCrimson]

Re: Hanns-G HH191/HSG1070

Rusty: would you mind checking the value of C806 for me? It's in the center of the psu-board. I have the same layout, but somewhat less components on the left side area of the card (On that Fujitsu display)

[Rusty!]

Re: Hanns-G HH191/HSG1070

Yeah no problem, I'll have a look tonight... I plan to be back in the thick of it again, as I've got my hands on another 19" panel now (the aforementioned broken one, I've popped the trashed LCD out of it leaving just the backlight and frame now).

Edit: What sort of values should I be looking for on C806? I only have a basic multimeter, so capacitance values are out.

[selldoor]

Re: Hanns-G HH191/HSG1070

I think he just means for you to tell him what it says on the side. I think I can see it in your great picture - 10uf 50v - but better just check.

[Rusty!]

Re: Hanns-G HH191/HSG1070

You're right on both counts, it is a 50v 10uf cap, and the problem was the ccfl's, the screen stays on with new ones bodged in (they didn't quite fit as they came). Great diagnosis, you're like the House of LCD's

[selldoor]

Re: Hanns-G HH191/HSG1070

Glad to have been of help - pleased you got it fixed.

[Rusty!]

Re: Hanns-G HH191/HSG1070

Semi-fixed. I think I might have ballsed the T-CON when stripping & rebuilding the panel as it now* has faint vertical lines on the screen, and it's present on the OSD so it's not being fed a bum signal.

Whoops

*Well, I say now, it could well have been like it beforehand as I wouldn't have noticed with it only staying lit up for a second.

[mcdaydavies]

Re: Hanns-G HH191/HSG1070

You may have knocked the lvds connector loose. Try and re-seat it.

[Rusty!]

Re: Hanns-G HH191/HSG1070

Thanks, gave it a try (along with anything else I disturbed during the process) but it still the same. Always the way, heh