Hanns-G 28" monitor 10 seconds to black issue

[Dax Corrin]

I've been following the 2 main threads regarding these Hanns-G power supply problems. I was able to revive 1 of 2 monitors successfully, and I have restored the "Blue light" to the second unit, but I still have a "10 seconds to black" problem with this one. I will start with the 24V circuit on the power supply and then move on to the inverter board. I'll also check to make sure I can see the image when I shine a light on the screen after it goes dark. I'll keep everyone posted on my progress. I'm very happy I was able to revive the first one again, as I've become quite fond of the 28" as opposed the the 22" I have used previously.

[Dax Corrin]

Re: Hanns-G 28" monitor 10 seconds to black issue

Update. I noticed the video has a bit of jitter before it goes to black, and shining a light on the screen reveals no video. Moving from backlight circuit to the logic board. I think I had to swap the logic board out of this one to the other to make one good one before the other failed again, and I have revived again. I'll be looking for a complete list of capacitors this board uses and swap them all out.

[Dax Corrin]

Re: Hanns-G 28" monitor 10 seconds to black issue

Final update: Took out the video/logic board, and swapped out the 2 100-16V caps nearest the voltage regulators. Replaced them with 100-50V, and put it back together. No jitter, and video remained on for 5 minutes+. I think they are good to go, both of them. I couldn't have done it without the knowledge on this forum.

[budm]

Re: Hanns-G 28" monitor 10 seconds to black issue

Great job! Are these the two caps you replaced?
http://s807.photobucket.com/albums/y...NNSG%20HG281D/

[Dax Corrin]

Re: Hanns-G 28" monitor 10 seconds to black issue

Yes, those 2 were the culprits. Now replaced with 100 uF 50V caps that I had on hand. It's currently humming away about 3 feet away from me on my daughter's computer, she's thrilled to have such a big monitor, I replaced a 17" 4:3 aspect ratio monitor with it. I'm using the first one I fixed that had additional power supply caps that didn't come in the repair kit fail a couple of weeks after I fixed it the first time, detailed in one of the other H-G threads.

[grazie]

Re: Hanns-G 28" monitor 10 seconds to black issue

Thanks for posting this information...very useful. However, getting the old capacitors out was more difficult than expected. Then I needed to clear the PCB holes from debris and solder. I used a drill bit that was slightly too large. So now two out of the four the capacitor lead holes open to two PCB tracks rather just one.

Any suggestions as to what I might be able to do to fix my impatience and stupidity? I've already looked into to getting a new logic board, but that doesn't seem easy either.

[Rtech]

Re: Hanns-G 28" monitor 10 seconds to black issue

Without a photo it is difficult to advise,BUT it is usually easy to put hard wire jumpers to reconnect broken tracks etc.

[Lumberjack777]

Re: Hanns-G 28" monitor 10 seconds to black issue

Thanks for posting this information...very useful. However, getting the old capacitors out was more difficult than expected. Then I needed to clear the PCB holes from debris and solder. I used a drill bit that was slightly too large. So now two out of the four the capacitor lead holes open to two PCB tracks rather just one.

Any suggestions as to what I might be able to do to fix my impatience and stupidity? I've already looked into to getting a new logic board, but that doesn't seem easy either.

Like Rtech said you'll need to solder leads to any connections that the traces lead to.

Through hole PCB soldering was very frustrating for me at first. The PCB board actually has little metal cylinders that go all the way through the board. And components get stuck going in, and coming out. I saw some guy on YouTube that talked about drilling them. I was thinking that was really bad advice.
I developed a system for through hole soldering that you might try in the future. To get a 2 lead component out, like a capacitor; just stick the tip of the iron on the solder and pull it out from the other side. You may have to work it back and forth a few times.
Now, we have a cylinder filled with solder and it might even be overflowing on top. GOOD. This is where I used to be frustrated. And that guy said to drill. NO!
What you want to do then is put a dab of flux on that solder. Stick your solder braid over the top. And place that hot iron over it and vacuum it out.
Once the wick starts that suction action; it'll pull all of that solder out and leave a nice clean hole.
With through hole soldering, too little solder won't start that suctioning action you need to really get a nice clean hole. I'm sure a solder sucker would do the job too. But the wick really does the job for me, if you add a little flux first.

[Lumberjack777]

Re: Hanns-G 28" monitor 10 seconds to black issue

One last little tip on through hole soldering. Occasionally you'll get the hole filled with solder that you just can't seem to clear out. First of all trim the leads down to maybe 3/16 to 1/4 inch so you don't have to push long lead through. As long as the other hole is clear......cut the lead of the hole that is filled with solder a little shorter. Then thread the longer one through the hole. Push the smaller lead up against the hole filled with solder. Dab some solder on the tip of the iron and touch it on the other side to the solder filled hole. Then push it through! Forget the guy on youtube that says to drill

[retiredcaps]

Re: Hanns-G 28" monitor 10 seconds to black issue

Occasionally you'll get the hole filled with solder that you just can't seem to clear out.

I tried a lot of things and what works best for me is a stainless steel bobbypin. Topcat uses a dental pick as per (other methods below as well)

https://www.badcaps.net/forum/showpo...45&postcount=7

[budm]

Re: Hanns-G 28" monitor 10 seconds to black issue

I use stainless steel dental pick also, works great.

[Lumberjack777]

Re: Hanns-G 28" monitor 10 seconds to black issue

I tried a lot of things and what works best for me is a stainless steel bobbypin. Topcat uses a dental pick as per (other methods below as well)

https://www.badcaps.net/forum/showpo...45&postcount=7

I use stainless steel dental pick also, works great.

That is a GREAT idea guys. Thanks. *~*~Merry Christmas~*~*

[grazie]

Re: Hanns-G 28" monitor 10 seconds to black issue

Thanks for all the replies. I'll read them more carefully. In the meantime I've attached a couple of photos. I've done repairs to broken tracks before, but what I'm concerned about is that because the hole is now too big, I may make connection to two tracks when the new capacitors are soldered in.

And I've found out that Hanspree EU won't supply spares. All they offer is a repair service. Maybe I'll send them the logic board if I can't make good what I've done.

[selldoor]

Re: Hanns-G 28" monitor 10 seconds to black issue

This is my repair suggestion for one of the pairs - Problem is that it is a double sided connection -I have to go but will look at the other later - hope you can understand it. Difficulty may be soldering the bridge to that trace that goes right across without soldering it to the negative side.

[grazie]

Re: Hanns-G 28" monitor 10 seconds to black issue

Thanks for taking the time to suggest this. However, I think soldering wire bridges across the capacitor holes is going to be very tricky. Would small pieces of component leg wire be suitable?

[selldoor]

Re: Hanns-G 28" monitor 10 seconds to black issue

Yes, should be fine - You may need a small drop of epoxy to give a bit extra support.

[selldoor]

Re: Hanns-G 28" monitor 10 seconds to black issue

Perhaps something like this for the other cap?
Its difficult to tell if you can use both ends of that small ceramic?
If not scrape down to trace and attach
Good luck.