Dgm l-2442wd

[FatPope]

Hi guys,

I have a DGM (Digimate) L-2442WD monitor that's been causing me some problems recently. I attempted a repair a couple of days ago which seems to have improved the matter slightly but it's still not fixed. I'm wondering if someone could give me some tips as to what to try next.

Ok, so, the story:

The Old Problem
I'd had the monitor for a few years when I noticed some issues starting to appear. It seemed to have trouble finding a signal when I turned it on, and over time it seemed to be taking longer and longer to display an image. The blue power light would flash and a high pitched noise would emerge from the monitor until eventually it would display something. Generally when it managed to display something it would be fine until I turned it off again, but occasionally the picture would start to flicker a bit. I did find, through rigorous scientific analysis, that both of these problems could be ameliorated by delivering a short, sharp smack to the top casing of the device. In time though even this stopped working and the monitor simply wouldn't display anything at all.

The Attempted Fix
So, after about a year of this seemingly dead monitor taking up space I decided to see if something could be done about it. From looking at similar problems people had both here and elsewhere it seemed as though dodgy capacitors could be the culprit. Opening it up I had a look at what I believe to be the power board. There I saw three purple Hermei brand capacitors, 1000uF 16V, with clearly bulging tops and signs of discharge. These were the only ones of that type on the board and all other elements had no immediate signs of failure so I decided just to replace those three. I ordered some Panasonic replacements from Farnell with the same specs and replaced the caps.

The New Problem
Turning on the pc after the repair I was initially hopeful when I immediately saw an image on the monitor. However, there did appear to be a large amount of blue static/noise over everything, which is obviously not ideal. Furthermore after a short while the screen went entirely blank again and wouldn't display anything. By fiddling around with the monitor layout settings in Windows 7 (I have a dual-monitor setup) I could get the screen to display something again but it would only last for ten seconds or so before going blank again.

It's interesting to note though that the previous problem of a flashing blue light and high pitched noise appears to be gone. Now the power light stays on as if it has found a signal, but just not displaying it.

Also, looking in the Windows screen resolution control panel the OS is noting the presence of the second monitor correctly, although it's also also showing what appears to be a third monitor, with the words "Another display not connected".


So, my question is, where should I go from here? Do these symptoms give any indication as to what's currently wrong with the device? Does this seem like I simply did a bad repair job? Any other thoughts?

I can get some pictures for you guys if you like but I'll have to open it up again.

[selldoor]

Re: Dgm l-2442wd

If you want to fix it your going to have to open it up anyway.
Post pictures using manage attachments jpg less than 3mb should be good.
First thing would be to check the cable from the main/logic board to the panel is ok. Suggest take it off and if it is a flat ribbon connector clean it (rubbing across with an eraser is good) then making sure it is firmly secured and when you come to put it back together try not to dislodge it. 3 caps may not be enough others may be off without shoing any signs.
Another possibility is your initial mechanical fix may have caused irreparable
damage to the panel/ tab bonds.
May be useful to check voltages on the connector from the power supply to the
main board

[FatPope]

Re: Dgm l-2442wd

Ok, so I tried cleaning and reseating the ribbon cable that goes from the logic board to the panel. It's very difficult to get at but I'm reasonably sure it's in correctly. Still the exact same result though unfortunately.

I've taken a load of pictures of both of the boards and marked where the new capacitors are. Apologies for the slightly crap quality, I have shaky hands and I was using my phone camera.

I hope I haven't wrecked thing permanantly, although that has been a fear. I was only using a 30W soldering iron and some of the connections just didn't want to come out easily. I did try to minimise the time spent directly heating each element though.

Regarding testing voltages and such. What exactly should I be doing and what should I be looking for?

Thanks!