28 inch Monitor won't power on anymore

[Surge]

Hey all, I hope this is the kind of thing I can find help with here. I'll try to provide info and pictures as needed, and include as much as I know up front.

0) It's a Hannspree HF289 28" monitor. I bought it in 2008 and it's been a very good monitor till the last minute. It cost almost $600 back then and it was the first time I invested in a good monitor. Really loved it.

1) The fault has changed over time. For a long time the thing would not go into standby when the PC was off. It would try non-stop, all night long, all day long, with the no signal screen reappearing the whole time. When I turned the PC on it would work fine though. Probably was like that for a year, maybe longer. At some point I had to unplug it from power to move it. When I plugged it back in the power light would flicker rapidly (not a pattern) and be kinda dim compared to normally when it's lit up solid. Hope that makes sense. It would then not turn on anymore. I let it sit with power connected and after half a day or so it suddenly came on and continued the above, trying to go to standby, fail, turn back on, no signal screen, try standby again, and so on. From then on I've always made sure it had power. If I had to move it to another room I would use a long extension cord and carry it to another room with power connected. Yesterday, I think due to some weather while I was at work, the power must have been out long enough for it to go back to the LED rapid amber flickering. I could not get it to turn on again. This time I decided to watch some Youtube videos about monitor repair and then opened it up to see if any capacitors were blown. I did not find any. They all look to be in good shape. I didn't take much apart. I really only felt comfortable taking out the power circuit board (where the power cord goes), and the one next to it where all the buttons and speakers were plugged in and that has all the ports on it like HDMI etc. I found nothing, and really didn't know what to look for besides blown caps, so I put it back together. Now the power light doesn't even flicker anymore. It is off, and does not even blink once or anything, there is no noise or anything else coming from the monitor either. The power button seems to be fine, does not seem broken.

2) History I guess I covered in #1.

3) It has always sat safely on my desk, out of the sun, in one of the bedrooms. No drops, always handled with care.

4) I looked over the two boards mentioned above and nothing jumped out at me. If helpful I could take pictures.

5) I've seen working devices with capacitors sitting at weird angles and such so I'm not sure how to spot anything wrong like that. I only know of capacitors that blow the top out, but I could reinspect and provide pictures.

6) As soon as I know what to take pictures of I can provide them.

Very grateful for any help with this!

Surge

 

[(*steve*)]

Yeah, my first guess is that you've got dead capacitors in your power supply. It's such a common fault (especially after a device has been literally powered up for years) and I've seen symptoms so much like yours that I would just go and replace them anyway.

Get a good photo of the power supply board (there is a resource showing you how to do this) and we can fairly quickly point out those capacitors which are the most likely suspects. (this will be the board that the power cable or socket is mounted on or connected to. It may be about 100mm x 100mm or thereabouts (it could be half this size, it could be double, but in that order)

It's important to replace the capacitors with good quality low ESR types, so just going down to your local Radio Shack isn't going to get you capacitors that will last very long. Tell us where you're located (country, state, and possibly city) and if you have any nearby electronics retailers and we may be able to point you in the right direction.

edit: By the way - Thanks for giving the information so clearly. You leave very little to ask for except the stuff you said you'd supply later!

 

[Surge]

https://www.dropbox.com/sh/yj14gzwprns7pog/AAA_J3GVRmhh9M0X5zvCcN81a?dl=0

I found the picture guide but don't have an overcast day or ideal lighting right now. I took some pics anyway just in case it helps get a look at it. If it's useless let me know and I'll try for better lighting.

Also the metal cage around some of the components doesn't come off on one side, so it's very hard to get a picture of anything underneath it.

I'm an hour north of Denver, CO. I found this site of a store that's supposed to be around here but I've never been. http://www.mselectronic.com/page/page/1197965.htm

 

[KrisBlueNZ]

The electrolytic marked "1" seems to have stretched. You can see that the plastic wrapping doesn't come as far inwards on the top as it does on the rest. This is a sign that it has been getting hot. So you should definitely replace it. Remove it from the board and post (a) the full list of markings on it and (b) the height, diameter, and lead spacing.

The electrolytics marked "2" are the output filter electrolytics, and they are the usual cause of problems. They look fine [No they don't; see edit], so you may want to leave them initially. Or you can just replace them on suspicion; in that case, post the same information.

The one marked "3" may also be an output capacitor.

Edit: Actually, I think the two "2"s at the top right have stretched as well, and maybe some others as well. You should replace any cap that looks like it has stretched. It might be best to just replace them all. At least, remove them all and inspect the bottoms for bulging, stretching, or leaking.

Steve, any corrections or additions to this advice?

 

[(*steve*)]

Steve, any corrections or additions to this advice?

They're awfully close to the heatsink, and it looked to me that surge had to remove part of the heatsink that covered the caps. All of this is going to be bad news for the longevity of these caps.

I'd probably replace the lot on the basis that going back to buy more caps and removing and replacing the PSU more than once is going to cost me more effort. The other issue is that if all of the caps are dodgy, replacing just some *may* get the PSU working again until the remaining caps get worse.

At the very least, remove the ones identified by Kris and take a look (and photos) of the bottom end. See if they're showing any signs of failure there. If you can beg, borrow, or steal (preferably not steal) an ESR meter then this will allow some very indicative tests to be done.

I'm an hour north of Denver, CO. I found this site of a store that's supposed to be around here but I've never been. http://www.mselectronic.com/page/page/1197965.htm

A quick look at their web site doesn't mention passive components (edit, actually they do). They may be worth a try (give them a call once you have a list of the capacitors you need). The alternatives in the US are places like Digikey, and Mouser. I'm not sure what their freight costs are to you, but you may find that purchasing all the caps at once is cheaper than purchasing some now and just one more later.

 

[Surge]

Finally got around to start working on this. Took all the marked caps off and wrote down the values on all of them.

10v 470uF x2
10v 1000uF x2
25v 470uF x2
25v 1000uF x2
35v 1000uF
35v 470uF

How do I know I'm getting low ESR types when I go for new ones?

Thanks

 

[KrisBlueNZ]

Low ESR electrolytics are normally described as such; if the description doesn't mention low ESR, it probably isn't. But it's best to try to match the original components' ESR as closely as possible. So we need to know the brand and series of those original electrolytics.

Can you post the full markings (not just the capacitance and the voltage ratings) for all of the original electrolytics. Also, where are you located? (So we know which supplier to recommend.)

 

[davenn]

Also, where are you located? (So we know which supplier to recommend.)

That's been done ... Steve covered it

 

[Surge]

One of them says this:

(M)105°C
7(7)
1Q

And on the other side it says "K Y"

That's it. Does that help?

 

[KrisBlueNZ]

OK, "KY" is just the lubricant they use when they slide the plastic bit on.

Just kidding. KY is the designation for a series of low-ESR electrolytics made by United Chemi-Con (UCC) in Japan. You can get exact replacements from Digi-Key. Use this filter: http://www.digikey.com/product-search/en?FV=ffec062a,fff40002,fff80009,340041,3400b7,b8367c,b8367d,b836a0,fc0013,fc0173,fc01ea&ColumnSort=63&stock=1&quantity=1

There are eight capacitor types listed there - two 10V, two 35V, and four 25V. You'll need to measure the dimensions of the 25V ones you have, to figure out which of the 25V ones to order.

 

[Surge]

Finally got around to ordering the parts, 1 type is out of stock, hopefully they get some more in. Thanks again for the link. I'll post back when I get them installed.

 

[(*steve*)]

You'll note that the link Kris gave lists numerous alternatives.

If you can tell me which one you can't get, I'll try to give you a similar list of alternatives.

 

[(*steve*)]

Assuming you have room, you can replace a capacitor with a higher voltage variant. For example, if there are no 10V 470uF capacitors, a 25V 470uF capacitor will do just as well (perhaps better)