For this entry I don’t have much to say progress wise though I do have some new thoughts worth mentioning. Many people claim that a new power supply momentarily fixes the issue, this may be because the new supply has been fried like the old one was, or, the new supply is handling the HV leakage differently, so progression of the tube degeneration has eventually caught up with the new supply also.

I have talked to Wacom and they seem fairly intent on fixing my Wacom with even the most arbitrary form of purchase evidence, none of which I have as the monitor is second hand (they sold me a lemon as it had the problem once with its first power on). New evidence along with this tells me they are probably aware they messed up in making their largest display use CCFLs, normally its fine but defects in some parts can cause early death, and the monitor has 6 inverters, which means its 6x more likely to fail early. Ill note the 22H and 13HD, and other models all use LEDs.

This is a cached snapshot Wacom appears to be removing from its sites and googles cache that makes mention of the fact the 24HD contains mercury, which also then suggests CCFL technology which is prone to breaking in this way. Wacoms site at this time no longer features this statement, or many other FAQs oddly. Of course its an easy miss, and fortunately very easy to fix and they seem very happy to replace or repair, often free of charge or at just the shipping price well outside of their warranty periods.

Next time I open the monitor, which will be when my workbench is sorted out and clean enough, as well as lit up enough since there are some lighting issues there, I will be well documenting the removal of one or some of the CCFL tubes and I will see what happens when I stick something else in there, as an indicator of what would happen if I put an LED strip in, fortunately when the backlight is in a failed state its safe enough to touch and the scope doesn’t read anything either. At very least ill just be shining a light into a hole.
Once ive taken measurements, experimented with the diffusion lens and have everything I need to order new parts ill put the tubes in backwards and see how long it takes for the monitor to break, assuming the tubes are not polarized, or would otherwise have some kind of problem with being reversed. Unfortunately, since the insulative wires use different materials as far as I can tell, I cant just swap the leads around, ill have to desolder and de/re-pot a tube to try this, assuming its not just a plug connection. Also any burns or discoloration will tell me the tube is likely beyond repair.

The documentation will be extensive, im hoping to make a guide or video tutorial to help others since this is a very simple to fix problem, or hopefully should be, I don’t know at this stage. Also, at some stage all the 24HD displays will fail this way anyway, same goes for earlier models before LEDs were being used, so it will be good to have floating around the internet. I expect soon many cheaper second hand monitors will go for sale in the summer months, as people try to unload their out of warranty lemons as what happened with me.

My warning to people is, if you cant replace it and the repair/postage costs to Wacom, make sure you test the monitor before you hand over the cash, have them use the monitor in an air conditioned room, power it on and listen for a buzz and the smell of ozone, and im not 100% on this but, if the backlight takes time for the light to build up after being off a while, that also may be an indicator. During this period there should be considerable buzz as I mentioned before.

Actually, don’t even get the 24HD unless you have a really big desk and dont intend for it to be a main display. Get the 22HD, its like half the weight, uses LEDs, less power (24HD power brick gets pretty hot).

Another note, when replacing the power brick/supply, any 24V supply will do, its also very easy to open (no glue, just 4 screws) and desolder the leads off the stock power supply, you don’t need a special supply, the 4 pins are just two sets of the same positive and negative which are parallel in the plug itself, the cord only contains 2 wires, unlike an Xbox 360 psu which has 12v, 5v, negative and possibly a fourth standby/power switch pin, the 5v however might actually be said standby, I only looked at one momentarily. Also be warned, one of the aluminium heatsinks in the PSU for the Wacom will shock you moderately if touched while on, though I had the earth disconnected at the time, still, follow normal safety protocol and do not touch while turned on.

Lastly, the HV negative/ground for the CCFL tubes is not connected to the same ground as the everything else. It goes through some sort of voltage splitter or comparator setup and possibly a boost converter, im not sure. All I know is that the negative/ground for the CCFL tubes is not the same negative/ground for the rest of the circuitry. Also please excuse my misuse of terms ground and earth. When I say ground I should be meaning the circuit ground or usually negative or 0V, and earth should be the earth that goes into the mains earthing pin which is physically connected to the buildings earthing rod. I may have misused “earth” when referring to a PC case, I think its earthed but im not sure.