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Old 06-08-2012, 03:25 PM   #101
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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I understand, what if I leave it on and just let it power down when I turn off the computer, will it last any longer?
No, not really. You will potentially end up with the issue some users have with Samsung TVs. The EEPROMs get corrupt and all the configuration data gets screwed up and then the TV requires an EEPROM reset. At least on Samsung TVs that is easy, but I don't know about monitors too much.

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Also how difficult is it to change the capacitors, I could possibly borrow a soldering iron and there is a Maplin store close where I could get them.
At least it's working now, any more use is a bonus until I get some spare cash in.
A Maplin "fire-starter" (mains plug on other end, no temperature control) iron is fine for the job, or you can borrow one. I bought a spare for 7. 25W or more is fine. DO NOT buy capacitors from Maplin - they are not low ESR (I have tried before, they are useless nowdays for components.) Caps which are not low ESR will fail shortly or possibly not work at all. They are also much more expensive!

I expect another week or maybe a month out of your monitor if you're lucky.

Open your monitor up. If you are strapped for cash let me know what caps you need and I'll add them to a Farnell order I'm making, they are 50p or so each.
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Old 06-08-2012, 03:40 PM   #102
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

I can afford the capacitors, it's just a new monitor that would be a problem but thank you very much.
Could you advise me of which caps I need to order, I don't have a clue which ones need replacing either but I guess I can tell when I have the new ones as I guess they will be very similar to the ones on the pcb.
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Old 06-08-2012, 03:47 PM   #103
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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I can afford the capacitors, it's just a new monitor that would be a problem but thank you very much.
Could you advise me of which caps I need to order, I don't have a clue which ones need replacing either but I guess I can tell when I have the new ones as I guess they will be very similar to the ones on the pcb.
I would advise you open your monitor up and report the caps used. Manufacturers have been known to change components in different production runs, even use entirely different power supplies.
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Old 06-08-2012, 03:50 PM   #104
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

Sorry, I misunderstood, I'll give that a go now
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Old 06-08-2012, 04:02 PM   #105
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

I've got the back off and the metal box with the electronics,.
there's two PCB's is it the large on I need to look at?
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Old 06-08-2012, 04:03 PM   #106
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

The one which has the plug connection on it or leads to the plug.
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Old 06-08-2012, 04:06 PM   #107
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

OK, got that off, there's two plates that look like heat sinks, one near where the power goes in and a smaller one the other end.
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Old 06-08-2012, 04:10 PM   #108
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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OK, got that off, there's two plates that look like heat sinks, one near where the power goes in and a smaller one the other end.
Take some pictures of the board. I'll highlight the suspected devices.
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Old 06-08-2012, 04:11 PM   #109
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

There are some small bee capacitors one end and some larger brown tubular ones the other, which ones need changing?
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Old 06-08-2012, 04:20 PM   #110
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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There are some small bee capacitors one end and some larger brown tubular ones the other, which ones need changing?
I'm not sure which ones you are referring to - a picture would be great - in general you want to replace the ones on the side closest to the connector going to the main board - there will be a black or white dividing line between the sides to indicate which side is mains/primary and which is secondary. Do not touch anything on the primary side with the monitor plugged in or shortly after turn off.
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Old 06-08-2012, 04:30 PM   #111
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

OK Here they are


Sorry for the delay, had to find some batteries for my camers.
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Old 06-08-2012, 05:04 PM   #112
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

No failed caps there - and they look like pretty high quality Chemicon KY. Red circle indicates the secondary caps. I think Retiredcaps said something about these Chemicons drying up because these monitors run hot, but I'm not sure.

One thing you can try to locate the faulty cap: Get your monitor into the non working condition. Use a hair dryer or hot air gun to heat up some of the capacitors. If it is able to turn on when you heat a particular cap, that cap needs replacing. In particular, I suspect the capacitors I've highlighted in blue as more likely candidates - and these ones *never* bulge when the fail. It is the startup cap, crucial to the monitor getting started, but less important when it's running. Thankfully, these caps are pretty cheap, like about 10p each...
Attached Images
File Type: jpg most-likely.jpg (383.0 KB, 86 views)
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Old 06-08-2012, 05:08 PM   #113
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

"t is the startup cap"
Is it the one on it's own, the resin around the pins has discoloured, looks like it might have overheated.
Would they be different values, I think the one on it's own says 50v 2.2 uF I can't see the other values until I get them out.

Last edited by NeilH; 06-08-2012 at 05:14 PM..
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Old 06-08-2012, 05:14 PM   #114
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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Is it the one on it's own, the resin around the pins has discoloured, looks like it might have overheated.
Yeah, it's the discolouring that has me worried - the cap may have simply been cooked (I've just had an LG TV which had a burnt area near a cap, the cap looks like it was cooked by whatever was very hot nearby.) Capacitors really hate high temperatures, especially the smaller ones, the electrolyte dries up.

For those as a temporary fix you can use caps from Maplin as they are less crucial. I would recommend using decent ones for greater longevity though.

Probably the one on its own is the startup cap, but replace all four to be sure if you can.
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Old 06-08-2012, 05:23 PM   #115
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

I'm surprised about Maplin, I thought they were pretty good so I'll see if there's any better suppliers here in Cardiff.
Thank you so much for all tour help Tom, I really didn't think I would be able to do this but you have talked me through it wonderfully.
I'll get on replacing them after the weekend as I have a lot on but I'll be sure to let you know how I get on.
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Old 06-08-2012, 05:48 PM   #116
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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I'm surprised about Maplin, I thought they were pretty good so I'll see if there's any better suppliers here in Cardiff.
Thank you so much for all tour help Tom, I really didn't think I would be able to do this but you have talked me through it wonderfully.
I'll get on replacing them after the weekend as I have a lot on but I'll be sure to let you know how I get on.
Maybe 20 years ago, when they still published a book of electronics projects, and half the store was dedicated to componentry, but nowdays they are useless.

There a Maplin book in my local library, it's kinda sad to see what they left behind. I think they've missed out big time because the internet and "Maker" revolution means that hobbyist/small time tech electronic component sales are going up, not down. If they just stocked a small amount of decent low ESR high quality caps I'd go there almost weekly to buy them, even if it cost a few quid more in total - I'd save on shipping, and get a TV working quicker, but they are too short sighted to see this.
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Old 06-08-2012, 05:57 PM   #117
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

I remember a friend at school used to build loads of gadgets he was always looking through the component book you mentioned and he got all his stuff mail order from them. They were really fast too, next day delivery at no extra cost for small items so you're right about being short sighted, with their old reputation they could probably have cornered the market.
I would like to get the best quality caps I can as I don't plan on doing this again soon, would that Farnell you mentioned send out such a small order if I can't find any decent supplier in Cardiff. Also is there any specific make or type I should look out for?
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Old 06-08-2012, 06:07 PM   #118
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

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I would like to get the best quality caps I can as I don't plan on doing this again soon, would that Farnell you mentioned send out such a small order if I can't find any decent supplier in Cardiff. Also is there any specific make or type I should look out for?
Farnell have no minimum order anymore (as far as I know), but there's a 5 shipping charge. RS Online is another source. eBay is okay, IF you buy from UK sellers and trust they are genuine - there are too many fakes on there so be careful.

Maplin have the advantage of 200 retail stores but they're just another PC World with disco lights and car stereos on top. And don't get me started on PC World... went in there to get 512 MB of RAM... they wanted 50... forget that! Bought some later for 18 from Crucial directly. (This was quite a few years ago...)
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Old 06-08-2012, 06:19 PM   #119
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

Looks like I might have to go to Maplin then, at least I wont have it going out on me, I can't use this 15" much longer. Don't get me started on PC world either. the prices are ridiculous like you say.
I built myself a computer two years ago (surprising how easy it was) and saved an absolute fortune going online. Same with Dixons mind, they wanted over 10 for a usb lead which I got online for less than 2, no wonder they're on the rocks.

I just noticed your rank "Badcaps veteran" you certainly are that.
Anyway, I'm off to bed shortly, I've got a busy day tomorrow so thank you again for all the help, you guys here are a treasure.

Neil.
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Old 06-08-2012, 06:24 PM   #120
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Default Re: Hanns-G HG281D 28" TFT - Multiple Problems

For the small caps I wouldn't worry about manufacturer, just match the capacitance and size. Voltage rating should be the same or higher. I would still recommend replacing the small caps with some good quality ones. Let me know which ones you need I'll send them to you free, to save you the cost of shipping from Farnell, if you find those caps appear to be the problem.
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