Hanns-G HG281D, LCD Monitor no power

[PieEyedPiper]

Re: Hanns-G HG281D, LCD Monitor no power

PieEyedPiper,
Reading your post it seems you did not recap the logic board, is that correct?
The kit you ordered only included the caps for the psu part then?
In my experience the HG281D comes with different revisions of power boards.
This -may- be the reason for the missing cap.

Personally I don't buy repair kits. I just make a list of all caps needed and buy them at the electronics shop in my town.
Often they don't have the right caps, then I just pull them from scrapped PSU's or motherboards.
You have to have a bit of experience as for what brands to use.

Looking at your post, I would start with the logic board. Skipping this part is just not recommended as you can read from other posts.
In my case the PSU was in good shape, but the logic board had cheapo caps and they were the root cause of the problem.

Cheers.

Thanks for the advice. Next time I will build my own list.
The kit is for the correct revision, the other small cap is probably just one of those things..only god knows.

Off hand does anyone know the spec for that cap so I can get a replacement? I think it was a 1uf 50v but I'm not positive.

Recycler, I find it interesting that your PSU was in good shape and it was your logic board that was failing. Perhaps it's because I'm new and I have not yet read everything but It seemed to me that most posts were indicating problems with the psu and the logic rarely had issues. Either way, if the small cap doesn't resolve the issue I will take your advice and start compiling a list for the logic board.

Happy capping!

[mmamuk]

Re: Hanns-G HG281D, LCD Monitor no power

It seemed to me that most posts were indicating problems with the psu and the logic rarely had issues.

I think most of the posts on this forum are indicating that if you have a CapXon capacitor (be it on the Power board or the Logic board) then replace them first as they are one of the worst, if not the worst, makers of capacitors.

Their Caps do NOT have "low ESR" or "low impedance" - this can be evidenced by the missing ESR values in their datasheets.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

@mmamuk - As your machine is complete and open can you post the details of that small cap for pieeyedpiper
Two small ones under the heatsink - if they are different please post values and the board number Cxxx.

[mmamuk]

Re: Hanns-G HG281D, LCD Monitor no power

@mmamuk - As your machine is complete and open can you post the details of that small cap for pieeyedpiper
Two small ones under the heatsink - if they are different please post values and the board number Cxxx.

If you can direct to where the heatsink is on the Board from post#287 (is it the large aluminium like structure with holes on the left side of the Board) I can possibly have a go at looking at the relevant capacitor/s.

The Power Supply Board details (taken from the top left corner of the board) are:
Model: PSM217-404--H-R
Rev: A1

If I'm not mistaken at looking at the correct capacitors, they are:

2.2uF, 50V (at the bottom edge, left of the board)

1uF 50V (like the above but displaced about 4cm from the bottom edge)

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

If I'm not mistaken at looking at the correct capacitors, they are:

2.2uF, 50V (at the bottom edge, left of the board)

1uF 50V (like the above but displaced about 4cm from the bottom edge)

Confirmed, if looking at the board with the Phihong Logo at the top right corner (REV A1 also).

I've just made a diagram of all my caps and polarity order of both boards so I can order replacement ones.

[PieEyedPiper]

Re: Hanns-G HG281D, LCD Monitor no power

Thank you!

[mmamuk]

Re: Hanns-G HG281D, LCD Monitor no power

You may find this thread helpful in terms of tools, techniques

https://www.badcaps.net/forum/showthread.php?p=211983

I'm thinking of prurchasing the following items of Solder, De-Solder Braid and Clamp Tool.

Any views on these, pros and cons?

My Logic Board doesn't state it is RoHS compliant but I have chosen the Solder and De-Solder Braid which are RoHS compliant as well as No SVHC.

I'm intending to use my Antex 25 Watts Soldering iron to de-solder and solder (reference Post#300).

Is the Clamp Tool, which is supposed to act like a Third Hand, of any use? Or am I just wasting money purchasing this?

Solder:
http://uk.farnell.com/jsp/search/pro...sp?sku=8400296
STANNOL - 593410 - SOLDER WIRE, LEAD FREE, 0.8MM, 100G

De-Soldering Braid:
http://uk.farnell.com/jsp/search/pro...sp?sku=1115541
MULTICORE / LOCTITE - NCOO 0.8MM 1.5M - DESOLDERING BRAID, 0.8MM, 1.5M

Clamp Tool:
http://uk.farnell.com/jsp/search/pro...sp?sku=1367049
DURATOOL - D00269 - CLAMP TOOL, WITH MAGNIFIER

[Rtech]

Re: Hanns-G HG281D, LCD Monitor no power

I find the de-soldering braid is easier to use if it is more than 0.8mm wide and I use
their code 959-9525.
The clamp Tool I have had for about 2 years and have used it twice,so unless you are extremely clumsy, or have lots of uses for it,not a great deal of help.
Minimum order value from Farnell is normally £20 prior to VAT, but then it is Free P&P.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

I think that with a 25w iron you will struggle to make satisfactory solder joints with
unleaded solder. If you look at the melting points you will see a 30 deg difference.
The board will conduct away a lot of the heat - you might get away with it in a warm room with the board preheated. Unless you intend to sell after repair I would use leaded.
If you wanted to sell at a later date you could make it clear that repairs had been done with leaded and even put a sticker on advising that.

Braid looks ok.

Clamp tool - id give that some serious thought I bought one as I had to solder a tiny
ceramic smd and needed the magnifier whilst soldering. The idea is good and in the picture they look good but you cant tell how small they really are. They are not heavy enough to hold most boards so you have to support anyway. The clamps never seem to be in the right place and I was frightened of it slipping and removing some of the smds. It was useful to hold the magnifier but otherwise I'd give it a miss and put the money towards a hotter iron.

[PieEyedPiper]

Re: Hanns-G HG281D, LCD Monitor no power

If it matters, copper braid was pretty much useless in comparison to a good solder sucker. My iron is an old Weller TC201T unit, 60watts. This iron is a tank and I personally used it for 8 hours a day, often forgetting to shut it off during breaks, for over 4 years. Who knows how many more it had done before I kidnapped it.

It's possible my equipment/old tip decreased the effectiveness of copper braid.

I'd agree that Helping hands/Clamps have a limited usefulness.

[mmamuk]

Re: Hanns-G HG281D, LCD Monitor no power

I think that with a 25w iron you will struggle to make satisfactory solder joints with
unleaded solder. If you look at the melting points you will see a 30 deg difference.
The board will conduct away a lot of the heat - you might get away with it in a warm room with the board preheated.

Braid looks ok.

... put the money towards a hotter iron.

My capacitors, lead free solder (0.8mm) and lead free copper braid (2.8mm) arrived yesterday from Farnell and with the excitement of a young kid I set about de-soldering a capacitor of a dud PCB board using my 25W Antex soldering iron.

For the first step I attempted to tin the tip of the iron. My iron eventually got hot enough to melt the lead free solder but, unlike the Youtube videos, it only flowed off the iron in small balls. So I used a wired pad, from the wash basin, to scrape the black gunge from the iron tip, until it was shiny and silvery. I attempted to tin the tip again and again the solder flowed off like a ball. It just didn't want to coat the iron tip with a thin layer that I had come to expect watching the Youtube videos.

Regardless I pushed on and attempted to desolder a component off the dud PCB board. With the copper braid nothing happened except for the braid getting hot along its length. Without the braid, the iron merely made a smudge mark on the soldered joint, the component getting hot and only a partial melting of the soldered joint.

So now I'm thinking that my iron is not upto the job and/or I have a wrong technique.

What a difference between watching it done on a Youtube video (effortless, clean and tidy) and practise (in my case).

I am now thinking of purchasing Maplins top of the line variable temp 60w solder station, currently at half price .....£39.99.

http://www.maplin.co.uk/60w-professi...tection-511927

Any pros and cons on this iron?

[Recycler]

Re: Hanns-G HG281D, LCD Monitor no power

Wow you kids can get stuff over there I only dream of...
Here are my tools:
soldering iron brand Techman

http://www.techman-usa.com/display.php?eC_type=DISPLAY&psid=TS-032&lang=en

Solder

http://www.techman-usa.com/display.php?eC_type=DISPLAY&psid=TS-500&lang=en

And an ordinary tinsucker. I've always used this sucker, they last about a year each.
I dont use "braid", can never get the pad clean no matter what.
Neither do I use clamps, but I have a magnifier glass to look at small parts.
As for the issue with the tip, it often happens and I just apply a little bit of solder paste. Then the solder will flow. I use this one:

http://www.la14.com/tiendala14/producto_ampliado.asp?CatalogName=base%5Fcatalog&CategoryID=07&RootCategory=07&ProductID=212179&sDimensions=width%3D200&sProductImageFile=images%2Fproduct%5Fimages%2F212179%5Fb%2Egif

For multi layer PCB's you may have to heat it up quite a bit (depending on your soldering iron), just take care to NOT damage any pads or tracks.
The old capacitor should come out slowly but steady.

Most of the times you will not be able to clear the hole of solder, don't worry, just heat it up on the bottom and slide in the new cap from the top.
It takes some practice but once you get the hang of it you do them all.

Cheers.

[selldoor]

Re: Hanns-G HG281D, LCD Monitor no power

I am now thinking of purchasing Maplins top of the line variable temp 60w solder station, currently at half price .....£39.99.

http://www.maplin.co.uk/60w-professi...tection-511927

Any pros and cons on this iron?

I never like to advise purchases - it depends on what you want to use it for and how often. Obviously it is better than the one you have.
I wouldnt want to pay that much for a one off job or even a few jobs a year.
Did see this one at CPC
http://cpc.farnell.com/duratool/d008...?Ntt=sd0167402

Then amazingly at Farnells for twice the price!!!!
http://uk.farnell.com/duratool/d0080...lug/dp/1568165
THEY ARE THE SAME COMPANY

Still couldnt justify buying one myself as I have a 20w 40w and 60w
so most bases covered.
They are duratool so you may be able to find one in any toolshop if you're interested.

[Vizor]

Re: Hanns-G HG281D, LCD Monitor no power

Anyone wanna sell their Main Board? :P

[Vizor]

Re: Hanns-G HG281D, LCD Monitor no power

or tell me where i can buy one?

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

Well my face is like this right now ->

I replaced some caps on the power board and now the monitor is working and powering on fine. Still yet to test it for longer periods but it's looking good so far.

I did damage a few traces being lazy and trying to rush it plus I should have used a better soldering tip, however I managed to fix them by using a few wires to reconnect them.

I found this youtube video very helpful, made me realise I should get a better soldering iron and tips suitably sized for the joints.

http://www.youtube.com/watch?v=vIT4ra6Mo0s


I tried uploading the spreadsheet I made for the capacitors needed for this monitor but the forum won't let me so here's a link to download the spreadsheet.

http://www.mediafire.com/?16ggw7dgd68ch4o

Hope this saves others time when looking for capacitors.

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

I found this youtube video very helpful, made me realise I should get a better soldering iron and tips suitably sized for the joints.

http://www.youtube.com/watch?v=vIT4ra6Mo0s

The above soldering videos are some of the best ever made. We know about them and highly recommend them.

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

The above soldering videos are some of the best ever made. We know about them and highly recommend them.

Silly me I should have looked around the board a bit more to find them.

Even though the video is old and it's not in HD on youtube the videos are still clear to see and understand.

I've learnt so much in just that one video than what I understood from various videos on YouTube.

[retiredcaps]

Re: Hanns-G HG281D, LCD Monitor no power

Silly me I should have looked around the board a bit more to find them.

CuriousInventor also makes excellent soldering videos.

http://store.curiousinventor.com/guides/

And Dave Jones at eevblog has a 3 part tutorial (search for soldering tutorial)

http://www.eevblog.com/episodes/

[mooses]

Re: Hanns-G HG281D, LCD Monitor no power

CuriousInventor also makes excellent soldering videos.

http://store.curiousinventor.com/guides/

And Dave Jones at eevblog has a 3 part tutorial (search for soldering tutorial)

http://www.eevblog.com/episodes/

Thanks retiredcaps, also bookmarked.

I just found out why my tip was wearing away.