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Old 02-20-2011, 10:13 AM   #41
algomez
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by jetadm123 View Post
Your monitor is under 2 years old. Isn't it still under warranty? It would be surprising if the cap(s) failed that quickly.
Yes, I tried warranty service but I don't have a receipt and Hans-G basically refused to service it.

So rather than just have it take space, I decided to try to fix it myself. Yes, I was rather surprised it failed so quickly too but the symptoms really match those described in this forum with the cap issues.

I'll let you know how it went. The caps should be here early next week.
-Alex
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Old 02-23-2011, 10:49 PM   #42
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Default Re: Hanns-G HG281D, LCD Monitor no power

No go. It was worth a shot I guess. I replaced all caps with Panasonic FMs except for the huge one. Same symptoms..turns on fine for 15min or so then shuts off. Will turn on again then shut off after a couple of seconds.

Anyways, I don't want to high jack this thread but I'll keep trying after I read more on this.

Thanks
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Old 02-23-2011, 11:24 PM   #43
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by algomez View Post
Same symptoms..turns on fine for 15min or so then shuts off.
Does it stay on longer if you point a fan at the power board? Logic board? Inverter board?
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Old 02-23-2011, 11:37 PM   #44
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Does it stay on longer if you point a fan at the power board? Logic board? Inverter board?
I will experiment with that this weekend and get back to you.

Thanks for the suggestion.
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Old 02-23-2011, 11:52 PM   #45
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Default Re: Hanns-G HG281D, LCD Monitor no power

When it shuts off, is the power LED still on? If yes, can you see an image if you shine a flashlight on it?
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Old 02-24-2011, 09:14 PM   #46
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Default Re: Hanns-G HG281D, LCD Monitor no power

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When it shuts off, is the power LED still on? If yes, can you see an image if you shine a flashlight on it?
Quote:
Originally Posted by retiredcaps View Post
When it shuts off, is the power LED still on? If yes, can you see an image if you shine a flashlight on it?
A. Power LED stays on.
B. No image when flashing a light on it.

I'll try the fan thing tomorrow.

Thanks!
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Old 03-13-2011, 11:57 AM   #47
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by algomez View Post
A. Power LED stays on.
B. No image when flashing a light on it.

I'll try the fan thing tomorrow.

Thanks!
I have the same problem with Algomez, with the exception that my monitor is branded as I-Inc with model number IF-281DPB. The power board looks exactly the same as submitted by Algomez, and the cap values are the same. I ordered the caps, and hopefully will solve the problem. My problem is somewhat similar to Algomez's with the exception that when the monitor is turned on when cold few minutes later the screen starts flickering, especially noticable when the background white. It later corrects itself and displays a stable picture for a while (random, something like 2 to 10 hours) then it turns itself off (with the blue power LED on). If I turn off the power (I have an external switch on the power control center for the monitor), and turn it on, it works for a while and turns itself off again. This is when I removed the back cover for testing and run it without the back cover. When the back cover is on, it behaves a bit differently, as when it turns itself off, pressing the power button or recycling the power, will keep the monitor running for 2 to 3 seconds before it turns itself off again. After few hours in turned off position, and the monitor cools down, I can turn on the monitor, and it stays on much longer (no 2 second switch off). When the monitor switches itself off the power LED is still blue.

I checked all the capacitors on the power board and all visibly look fine to me with no noticeable bulging or leakage. The caps are mainly "no name" brands and of KY type. the green caps (smaller ones) are Taicon brand.
The I-inc monitor is warranted for 1 year for parts and labor, while its Hanns-G twin is warranted for 3 years for parts. The manufacturer wants $100 to fix the problem as it is out of warranty (the monitor is two years old), however the shipping will be paid by me which would be a hassle as I threw away the box few months ago, and it would be expensive (the new model is $250 or less).

Algomez, have you progressed any further with your tests?

Thanks
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Old 03-13-2011, 04:02 PM   #48
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by mrboca View Post
The caps are mainly "no name" brands and of KY type.
If the caps are brown and have a little "crown" symbol on them, they are United Chemi-con caps. United Chemi-con generally makes good caps, but as other posts here show, they can dry out and have high ESR or be out of uF tolerance.
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Old 03-13-2011, 07:52 PM   #49
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Default Re: Hanns-G HG281D, LCD Monitor no power

United Chemicon KY are actually quite reliable, so don't replace them just yet. The fact that the monitor has problems after it warms up indicates that there may be a bad solder joint somewhere. Check the inverters first, especially the joints on the inverter transformers. Moreover, the ESR of capacitors tends to go down with temperature, so if this was actually a capacitor issue, the problem would become less severe when the monitor is warmed up than when it's cold.
Probably not a bad idea to replace the Taicon caps, though.
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Old 03-13-2011, 10:04 PM   #50
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Moreover, the ESR of capacitors tends to go down with temperature, so if this was actually a capacitor issue, the problem would become less severe when the monitor is warmed up than when it's cold.
Yes, totally agree with momaka's statement regarding ESR dropping after the monitor as warmed up.

My comments re the KY series is all based on helping others in 3 or 4 cases and finding out that the KY has been root cause similar, but NOT identical symptoms.
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Old 03-14-2011, 12:17 PM   #51
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by mrboca View Post
I have the same problem with Algomez, with the exception that my monitor is branded as I-Inc with model number IF-281DPB. The power board looks exactly the same as submitted by Algomez, and the cap values are the same. I ordered the caps, and hopefully will solve the problem. My problem is somewhat similar to Algomez's with the exception that when the monitor is turned on when cold few minutes later the screen starts flickering, especially noticable when the background white. It later corrects itself and displays a stable picture for a while (random, something like 2 to 10 hours) then it turns itself off (with the blue power LED on). If I turn off the power (I have an external switch on the power control center for the monitor), and turn it on, it works for a while and turns itself off again. This is when I removed the back cover for testing and run it without the back cover. When the back cover is on, it behaves a bit differently, as when it turns itself off, pressing the power button or recycling the power, will keep the monitor running for 2 to 3 seconds before it turns itself off again. After few hours in turned off position, and the monitor cools down, I can turn on the monitor, and it stays on much longer (no 2 second switch off). When the monitor switches itself off the power LED is still blue.

I checked all the capacitors on the power board and all visibly look fine to me with no noticeable bulging or leakage. The caps are mainly "no name" brands and of KY type. the green caps (smaller ones) are Taicon brand.
The I-inc monitor is warranted for 1 year for parts and labor, while its Hanns-G twin is warranted for 3 years for parts. The manufacturer wants $100 to fix the problem as it is out of warranty (the monitor is two years old), however the shipping will be paid by me which would be a hassle as I threw away the box few months ago, and it would be expensive (the new model is $250 or less).

Algomez, have you progressed any further with your tests?

Thanks
Unfortunately, I have not had a chance to do the fan test. I think I will have time tonight. I will post my findings right after.
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Old 03-14-2011, 08:58 PM   #52
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Default Re: Hanns-G HG281D, LCD Monitor no power

I went ahead and changed most of the caps which I received as the kit specific for this monitor. The ones I did not change were the 3, 10-microfarad caps at the primary part of the card.
I double-checked the polarities, solder joints etc, and while I was putting the monitor together, I forced the thin connector to the LCD controller card's (I guess that is what it is called?) female connector which is a thin, flimsy surface mounted type. The female connector came off the controller board, and i do not think I will be able to solder the connector back to the surface mounted pads. So I guess i need a new controller board (the one mounted over the power supply board housing).

Without this connection, I powered the monitor, with the PC connected to VGA port. All I see is a bright white screen, which seems to be staying on without turning itself off. I kept it like this for an hour with no problems. I also noticed that the monitor seems to run cooler.
Now the issue is where I can get a controller board for the monitor.
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Old 03-14-2011, 10:27 PM   #53
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Default Re: Hanns-G HG281D, LCD Monitor no power

Okay, I just ran the fan test and I get the same result. I pointed the fan to the power board, I turned on the monitor and it stayed on for about 5 minutes then it shut off and the blue power light stayed on. I hit the power button again and it would shut off. Turning on the monitor again would stay on for a few seconds then shutoff. I did notice shakiness in the screen text.

I pointed the fan at every circuit board aswell and same thing.

Not sure what's going on.
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Old 03-15-2011, 02:32 AM   #54
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Default Re: Hanns-G HG281D, LCD Monitor no power

Quote:
Originally Posted by mrboca View Post
I went ahead and changed most of the caps which I received as the kit specific for this monitor. The ones I did not change were the 3, 10-microfarad caps at the primary part of the card.
I double-checked the polarities, solder joints etc, and while I was putting the monitor together, I forced the thin connector to the LCD controller card's (I guess that is what it is called?) female connector which is a thin, flimsy surface mounted type. The female connector came off the controller board, and i do not think I will be able to solder the connector back to the surface mounted pads. So I guess i need a new controller board (the one mounted over the power supply board housing).

Without this connection, I powered the monitor, with the PC connected to VGA port. All I see is a bright white screen, which seems to be staying on without turning itself off. I kept it like this for an hour with no problems. I also noticed that the monitor seems to run cooler.
Now the issue is where I can get a controller board for the monitor.
post some pitcures of the cable and conector,there maybe a way to repair it.I can see the board being realy expensive, if you can even find it
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Old 03-15-2011, 02:40 AM   #55
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Default Re: Hanns-G HG281D, LCD Monitor no power

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Originally Posted by algomez View Post
Okay, I just ran the fan test and I get the same result. I pointed the fan to the power board, I turned on the monitor and it stayed on for about 5 minutes then it shut off and the blue power light stayed on. I hit the power button again and it would shut off. Turning on the monitor again would stay on for a few seconds then shutoff. I did notice shakiness in the screen text.

I pointed the fan at every circuit board aswell and same thing.

Not sure what's going on.
I don't see a pitcure of the inverter anywhere in the thread,It would help to have one.
Are any of the pin voltages from the power supply to the inverter Identified?
Can you see if the backlight on siginal is staying the same voltage when the lamps turn off?
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Old 03-30-2011, 07:32 PM   #56
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Default Re: Hanns-G HG281D, LCD Monitor no power

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post some pitcures of the cable and conector,there maybe a way to repair it.I can see the board being realy expensive, if you can even find it
I found the picture of the card from the other Hanns-g 28 thread. Someone kindly put the pic on Flickr.

Here is the link

http://www.flickr.com/photos/6117624...n/photostream/

The connector in question is the 30 pin shielded LVDS female receptacle which accepts a "blade" type male connector of an LVDS cable from the other board. The connector is at the top of the board covered with orange transparent isolation sticky tape.

I tried to find the connector online but I was not very successful. Any suggestions regarding the connector part number and where I can get it?

The soldering of the connector on the board pads will be a hard task considering that the connection pins are 1 mm apart.

The alternative is to replace the board, that is if I can find a replacement. I replaced the caps and I think the power supply is functional, and if I solve the connector problem, I believe I will have a working monitor again.

Thanks in advance for your help.
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Old 03-31-2011, 06:34 PM   #57
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Default Re: Hanns-G HG281D, LCD Monitor no power

Soldering that connector won't be very difficult with a standard iron and a few tips. If you have a little bit of experience soldering check out this tutorial at sparkfun:

http://www.sparkfun.com/tutorials

Click on the 'surface mount soldering tutorials' section and read through them. They have helped me with my SMT practices.

I bet Mouser would have that connector. I glanced through their catalog and found a 'FI-R flex' connector that looks similar. It comes in a 31 pin package (that is what I counted in the pic). I can't remember the details of my monitor to verify if that connector would work. You need to measure the pin spacing, count the terminals and calling Mouser about it wouldn't hurt.

For starter, here is the part number I found: 656-FI-RE31S-HF
You will need to verify that it will work.

Last edited by ehren; 03-31-2011 at 06:41 PM..
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Old 03-31-2011, 07:11 PM   #58
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Default Re: Hanns-G HG281D, LCD Monitor no power

I need to change some of that info.

I looked a little more and I need to change my response to reduce possible confusion. I think that I found the cable side: FI-X30HL-KITASSY-300M
Also the Sharp that I am working on has the same connector. No number. You could easily get an answer from Mouser which connector you need from that cable. Manufacturer is JAE. It's called a LVDS cable and you need a 30 pin latched receptacle.

Also found this one, but there is no detailed data sheet or picture. This is a 30 pin locking receptacle: 656-FI-XB30SL-HF10
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Old 04-12-2011, 01:19 PM   #59
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Default Re: Hanns-G HG281D, LCD Monitor no power

Does anyone know who sells the main transformer for this monitor? The P/N is:

26002170001 PHIHONG
E149666 FIS-B1
904040-001 0725 RA3
HI-POT
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Old 04-12-2011, 08:02 PM   #60
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Default Re: Hanns-G HG281D, LCD Monitor no power

In the event that I cannot procure this transformer individually I'm assuming that the only way to fix my power supply board would be via replacement. Nobody seems to have stock nor have they had stock for some time.

For the folks who know this board pretty well, would it be possible to jumper a 12V and 24V regulated power supply to the location of the transformer pins? That would cover 6 of the 7 pins on the output side near the connectors (i.e. 2 x 12V, 2 x 24V 2x ground). The middle pin however is connected to a diode. I'm not sure what to do with him. If this would work, this would cover the 12V and 24V output, but not the 5V output. I don't get 5V although I do get 5VSB. Is the 5V derived from the 12V or 24V transformer output or do I have another board problem?

Alternatively, if another transformer would work even if the pin out wasn't identical, I wouldn't have a problem jumpering wires.

Any help is appreciated. It would be nice to salvage this monitor as I am very happy with the size and picture quality..
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