Packard Bell Viseo 191WS 2 seconds to black

[Demix]

Basically, my girlfriends sister's monitor decided to die on her a while back. At the time I wasn't feeling up to the task of looking at it properly so I asked her what had happened. She said it just cut out and she smelt smoke. No problem I thought to myself. If there is smoke then I can find the source of the damage... However, When I opened the monitor up I found no damage at all, apart from the shockingly crap caps that the manufacturers had used. I replaced all of the caps on the inverter, apart from one (a large 82uf 400v samxon one which looked fine) and I put the monitor back together, pretty confident it would work. Alas, it wasnt that easy, so I gave up and she ended up buying a new monitor. Right, now on to the current situation. I saw the monitor laying by the bin ready to be trashed so I asked if i could take it anyway to have another go at it, which I was told was fine. Since then I've checked all 4 CCFL's and the solder connections on them - they are fine. I did this because while I was testing the tubes by plugging them in 1 by 1, one of them would make a hissing sound prior to shutting off - which I'm pretty sure was the transformer closest to the tube plugged in. I kept testing and this somehow decided to go away, which slightly baffles me actually. Anyways, when I'm back from work tomorrow and not so sleepy, I intend to re-solder the transformers and a few other areas of interest, but other than doing that I'm not too sure what to do from here. I feel bad everytime I post here as it must really seem like im not learning, but i promise i am! its just taking a while to sink in hehe ^^ anywho, here are some pictures, thanks guys - I just wanted to add, I keep getting a random smell of electronics/burning, but nothing is getting hot and I can't find the source. I read this could be leaking 'eco' from the CCFL's, but they seem okay. I would test them with a different inverter or I would try different CCFL's if I had any... I do have a CCFL case kit but the connectors are wrong, and I would rather not mess with my CCFL's in my case as ive already had to re-solder the wires once due to me tearing it out accidentally xD

P.S I know the solder joints for the caps i replaced look terrible.. it's because I did it at my girlfriends house using her dads soldering iron... which has a pretty chunky horrible tip, plus I was rushing.. so I do intend to fix the mess i made and use a little pcb cleaner :P

[PlainBill]

Re: Packard Bell Viseo 191WS 2 seconds to black

Pretty amazing. 12 full lines of test, and no list of symptoms.

Does the power LED come on?

Does the screen appear to light, even briefly?

Have you checked the output voltage from the power supply?

There are several points that could be overheating without producing visible signs. The leads to the CCFLs and the inverter transformers come to mind.

PlainBill

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

My apologies. It was rather late when I posted and I somehow had it in my head that I had already listed the symptoms xD

Power LED comes on, The screen runs fine for a varying amount of time. Sometimes it will be 2 seconds, other times it lasts a whole... 8 seconds lol. I have yet to check the output voltage from the power supply but I will get on to that as soon as i get home this evening. As for the CCFL leads, I will check them out later and possibly tear apart another similar screen to test with. The inverter trasformer is probably the source of the smell/short hiss from what I can tell. I have yet to figure out why the hissing has stopped though. Anywho, when I get home I will run some more tests, including a proper test of the ccfl's and I shall also re-solder some of the iffy looking joints.

Thanks for the input, PlainBill. It seems whenever I've had a "project" like this and I've come here, you've always been able to help (Amongst all of the other fantastic people who have aided me in the past.)

Right.. off to work I go =]

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

Okay so I got a little sidetracked on this, but since then ive confirmed the CCFL's are all working correctly (using a different inverter) I've re-soldered the questionable areas but now im out of ideas. I may just invest in two new transformers If i can find similar ones on ebay or a specialist site

[PlainBill]

Re: Packard Bell Viseo 191WS 2 seconds to black

One thing to check is the resistance of the secondaries of the inverter transformers. They should match to within 3%.

PlainBill

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

Thanks a lot. I would check that now, but it seems I killed it completely. Me being the idiot that I am, went to test it and forgot I had it laying against the metal casing of the screen panel... lets just say my ears are still ringing. Im pretty sure ive blown a fuse somewhere as now i get no power at all hah. If I cant figure out what I blew then I guess I will give up on this project for the moment >_< Thanks for the help anyway

edit: its not the plugs fuse by the way, I checked that and it was fine.. I defo shorted something on the PCB lol sigh! Whats worse is I think I had managed to fix the initial problem.. there was an extemely messy solder line which connected two bits that wern't supposed to be connected - i cleaned this up

edit 2: I have a bit more info on this board. I was just looking about and I think I may have found the fuse I've blown, plus there is something which stuck out that I didnt notice before, as as far as I know the component in question generally doesnt fail o.O its a small blue flat round cap (I think) labeled C23 - While comparing it to the other blue flat caps that look the same I noticed that this one seems almost blackened somehow. I will attach pictures of this plus the possible fuse I blew - (labeled F1F) Sorry for the trouble here. Also the component labeled PC1F smells a little toasty, so I thought I would mention that. It may not be anything related.

PS. To test T1 and T2 I know that the outter pins are the secondaries.. but what setting do I put my multi meter on :P I'm so sorry for being such a novice, but we all start somewhere.

If you need any other information then please ask =] unless it's "seriously.. were you dropped on your head as a baby? who puts a pcb against a metal plate!" lol

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

I can confirm the thing I thought was a fuse, in fact was, and it was gone. At first I couldnt find any information on the fuse as it said "RSFR-H" on the side.. then I realised this was a type of shrink wrap ¬_¬ so I removed that to find the fuse underneath. On the fuse is "3N T2A 250V" So i will try and find a suitable replacement. Thanks again for the help, and hopefully I will figure this out soon hehe :P

would this be a suitable replacement? -
http://uk.rs-online.com/web/p/fuses-cartridge/7032629/

Thanks

[PlainBill]

Re: Packard Bell Viseo 191WS 2 seconds to black

Sooner or later most people do something really stupid when learning to repair electronics. Have you identified the location of the points that were shorted by contact with the metal plate? I see one spot that looks suspicious, if it occurred in the neighborhood of R5F and D201?, more than just the fuse might have been damaged.

PlainBill

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

I will be honest, that area is actually a result of shoddy solder work which I attempted to fix. I think I may have scorched the board a tiny bit with the soldering iron, but it was not the part which touched the metal casing. Im pretty sure that (i guess i can call it lucky) the part of the board that touched was around the fuse area that actually blew. I put the pcb back against the metal (obviously no power this time haha) and its the only part of the board that touches, as the rest has the little rubber pads intact and it keeps it just floating above the metal. Ive ordered a new fuse and im looking in to testing the transformers properly. I found a few good videos on youtube showing how =] I know I had to check the resistance and make sure it was within 3%, but im that much of a novice that I didnt know what setting to put the multi meter on. Also something I didnt mention, though it may not be all thats important. When the backlights went out after a few seconds, the solid blue power led just flashes for a while, as in the whole "No signal" style of flashing. - i have no input plugged into the monitor during this. Thanks again. I will test these transformers and wait for my fuse for the time being.

Edit: tested them and they both match to almost the exact same, only .01 difference in fact So I guess I can rule those out. Back to the drawing board >_<

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

I really wish I could edit posts rather than having to make a new most. I feel like i'm spamming a lot. Anyway, I tested the transformers properly and after doing more research and reading (I read the comprehensive guide written by retiredcaps, which was extremely helpful). The transformers are as follows -

Using Multimeter set to 2k ohms

T2: | T1:

1 to 2 - .001 | 1 to 2 - .001
1 to 3 - .001 | 1 to 3 - .001
1 to 4 - 1 | 1 to 4 - 1 - earthed? (It's the pin which is not connected to anything, right in the middle)
1 to 5 - .001 | 1 to 5 - .001
1 to 6 - .001 | 1 to 6 - .001
1 to 7 - .001 | 1 to 7 - .001

Secondaries - .945 | Secondaries .944

as for pin 2 to 3, 3 to 4 etc, they are all .001 as well, on both T1 and T2

I decided to check D3F and D4F (The two MOSFET looking things along the heatsink
from them using the multimeter on 200 ohms setting I got this -

D3F

pin 1 to 2 - 1 (too high to read it? - it flashes up with a high number before going to 1)
pin 1 to 3 - 00.8
pin 2 to 3 - 76.1

D4F

pin 1 to 2 - 1 (too high to read it? - it flashes up with a high number before going to 1)
pin 1 to 3 - 00.7
pin 2 to 3 - 95.4

I also checked the Diode - D5F as It could be a possiblity, but the results were :

nothing 1 way, and the other on 2k ohms was around 452.

Thanks again for the help and I really want to be able to get better with these things so I don't need to ask so many questions. I really want to be able to give back to the community one day when I know what I'm doing

Any other tests I need to do then please just let me know and I will do my best to get you the numbers / pictures, etc that you need.

[PlainBill]

Re: Packard Bell Viseo 191WS 2 seconds to black

RE: Editing posts. The technique is to figure out what you want to enter, enter it all, then post it. IF I figure out how to do that consistently, I'll let you know.

The secondaries match. I note you have already replaced the caps. If you used low ESR caps (please verify brand and series you used), the problem is either the wiring to the CCFLs, or the CCFLs themselves. A common failure point is the solder joint between the CCFL lead and the CCFL itself. If you are lucky, the panel has the CCFLs in slide out holders.

PlainBill

[Demix]

Re: Packard Bell Viseo 191WS 2 seconds to black

The caps I used were Panasonic FC series, low ESR. I purchased them from RS Components. As for the CCFL's. I've already pulled them out completely and tugged on the wires. I even removed the rubber caps as best I could, to find that solder connection was in fact solid. Plus all 4 CCFL's light up perfectly one by one using an old laptop inverter I had laying around. I didnt play for too long but they seemed to be running fine using that inverter without going out or making any sounds at all. Thanks

When my new fuse gets here I may even be lucky enough to find that the screen works once ive replaced it, due to the bad solder lines which I cleaned up prior to blowing it. I will report whats going on with it in a few days when the fuse gets here. Thanks again