2 seconds to black on HNC IH252 HPB Monitor

[2smoovedaddy]

Have a Hnc monitor with the 2 seconds to black. trying to isolate the issue to the bulbs. When I powered it on after a couple seconds it shuts off but the power led stays green not amber. Do those ccfl's run in series? Would one cause them all to go out or cause the voltage drop. Thanks!

[2smoovedaddy]

Re: 2 seconds to black on HNC IH252 HPB Monitor

Just shined a flashlight in the dark and could barely make out the screen. Would one of the bulbs cause a voltage drop or the inverter. Thanks!

[budm]

Re: 2 seconds to black on HNC IH252 HPB Monitor

It has 4 individual lamps, if one is bad (draws too much current due to ages, or will not fire and conducts current) the whole Inverter circuit will shutdown.
Please read this:
https://www.badcaps.net/forum/showthread.php?t=10419

Here is pictures of bad lamp and tester lamp:
http://s807.photobucket.com/albums/y...klight%20lamp/

http://s807.photobucket.com/albums/y...g%20old%20CFL/

[2smoovedaddy]

Re: 2 seconds to black on HNC IH252 HPB Monitor

Thanks Budm. Here's the backlamps. They look bad according to the pics in the link you sent me. The first 2 pics are one set and the last 2 pics are the other set. What are your thoughts. Thanks!

[selldoor]

Re: 2 seconds to black on HNC IH252 HPB Monitor

With them out of the panel try connecting one set at a time They wont stay on but you might be able to pin the problem down to an individual bulb.
Care as high voltage involved = do not hold the bulbs.

[2smoovedaddy]

Re: 2 seconds to black on HNC IH252 HPB Monitor

Thanks Selldoor I did what you said and one of the bulbs was pink when it turned on so I'm assuming that's the bad bulb. The others were fine.

[budm]

Re: 2 seconds to black on HNC IH252 HPB Monitor

Yes, you have bad lamp.

[jkesa]

Re: 2 seconds to black on HNC IH252 HPB Monitor

I also had the 2 seconds to black problem with my own I-INC IH252HPB monitor, although sometimes it was more like 10 to 15 seconds to black. I first tried moving the jumper on the inverter board from the 7.5ma position to the 8.0ma position with no luck. My IH252 inverter board looks the same as this one in this YouTube video : http://www.youtube.com/watch?v=NQBTKzpuEqI

I had a 19 inch Viewsonic VG930M-3 monitor on hand with a smashed in lcd panel that I was saving for parts, but with strong backlights. After disassembling the Viewsonic, it turned out it was also made by the Hannspree group and had the same connectors for the CCFL lights as the IH252, nice . In order to test the CCFLs on the IH252, I connected a CCFL from the VG930M to the IH252 inverter board, testing each of the 4 CCFLs on the IH252 one at a time. At any one of the 4 connections made, the other 3 CCFLs would remain lit and bright and no flickering, so I knew all 4 CCFLs in the IH252 were in good shape. But with all the IH252 CCFLs plugged into the IH252 inverter board, it would still get 2+ seconds to black syndrome.

Even though none of the TAICON capacitors on the inverter board were bulged or leaking, I replaced all (12) but the very largest one with Japanese Panasonic and Chemicon capacitors, thinking that one or more of them may have changed value. NO LUCK, I still got the 2+ seconds to black syndrome.

Puzzled at this point and not willing to spend much time and money on it, and with the 25 inch monitor still being acceptably bright with just 3 CCFLs, it was time for some good ole jury rigging, heh.
With some (real, not plastic) aluminum duct tape, I taped one pair (with the holder) of the VG930Ms CCFLs to the back metal plate of the IH252 as there was plenty of room. I remounted the stand and the bezel leaving the back cover off and went about using the monitor as usual.


About a week later, I said what the hey and plugged in the 4th IH252 CCFL. Low and behold, NO MORE 2+ seconds to black syndrome. The monitor now stays on with all 4 original CCFLs plugged in, now still going good for 4 days, knock on wood.

Im not totally sure what is going on, but I suspect at least one of the TAICON capacitors werent holding a charge, and that it took some time for the Japanese caps to charge up.

Any thoughts ?

Anyway, maybe someone else will find my experience useful.

[sukmir70]

Re: 2 seconds to black on HNC IH252 HPB Monitor

I'm having a similar problem. When the problem began, every few days the monitor would go to black for a few seconds then come back up and work fine until it repeated to process again in another few days. While the monitor went black, I could hear a hissing white noise coming from the back on the side of the power board. When the monitor came back online, the hissing ceased. Yesterday, The monitor blacked out and would not come back on. If I powered it off and then back on, it would remain lit for 20-30 seconds before dying again. during that brief time, I was able to adjust the brightness to zero, and now the monitor is working. When the monitor was blacking out I could see that it wasn't off, but was dark. I opened the monitor and inspected all the caps. I don't see any leaking or bulging in any. Since it works with the brightness turned down, I wondered if anyone had any ideas as to what is wrong. I know caps can be bad while appearing normal. Any insight anyone could provide would be appreciated.

[budm]

Re: 2 seconds to black on HNC IH252 HPB Monitor

Post good clear pictures of YOUR board so we can see what are dealing with.

[fluteboy]

Re: 2 seconds to black on HNC IH252 HPB Monitor

I have an IH252 which just shy of 4 years old decided to start doing this 5-10 seconds on before swiftly going blank.

Like sukmir70 I found that lowering the brightness seemed to cure the problem, so am now running it at 25% brightness.

A few months prior to this issue starting I noticed upon switching on the monitor, the bottom of the screen would have a pinkish tint which would slowly fade. With this, I am assuming the backlights are on their way out.

I decided to open the unit and inspect the capacitors, and none of them look blown-out or leaky, so I doubt that the capacitors could be at fault here.

I did not go as far as removing the backlights for inspection, but can anyone advise on the make and model of these backlights, or possibly a suitable replacement for them? Directions to a suitable backlight outlet will also be of help.

Thank you in advance.

Ray