Backlight randomly shuts down

Tom · Post by **Tom** » Thu Aug 11, 2005 3:29 pm

That will work, but you shouldn't have to do that. If the unit froze, then that won't work. Also, what is the pcb revision on your MX4s?

harley7892 · Post by **harley7892** » Fri Aug 12, 2005 6:34 am

Hi Tom

I'll get you that revision number when I get home tonight. Last night I hooked up two units and put them on the "relight the unit" routine. (Just to see if it works. Didn't see anything strange and let it run an hour (short for time)). Tonight I will take the routine off and just let them run. Will report back on findings.

harley7892 · Post by **harley7892** » Wed Aug 17, 2005 1:21 pm

Well I hooked up three units directly to the mobo (skipped the hub), reset the ports, reloaded the drivers. Let them run for an hour and they didn't shut down or turn the backlight off. However, I get garbled characters on one of the displays fairly often, and sometimes the events I program in LCDC dont function. But just for the heck of it and my own paranoia, I set up an event in each unit to turn the backlight on after every set of screen cycles. Kind of primitive, but so far so good after two days.

harley7892 · Post by **harley7892** » Wed Aug 17, 2005 1:22 pm

Oh, and all four of my units are Rev 1.1 (more noise tolerant I have been told.)

Tom · Post by **Tom** » Wed Aug 17, 2005 1:56 pm

Do the test include no fans being connected to them?

harley7892 · Post by **harley7892** » Thu Aug 18, 2005 6:34 am

The one unit, an MX4, has four fans and a floppy connected to it. This is the unit that shows the most interference in display characters and backlight problems.

Tom · Post by **Tom** » Thu Aug 18, 2005 9:56 am

I think some of your fans are generating some noise, so it's causing the backlight to turn off and on. If you left the unit running without the fans, you probably won't see that problem.

Best Regards,

harley7892 · Post by **harley7892** » Fri Aug 19, 2005 8:54 am

Well I could do that, but that would defeat the whole purpose of the fan control gpo and temp control gpo. I guess I'll just live with it, maybe wrap the usb cables to try to insulate the noise.

It seems the units are sensitive to electrical noise, so I'll try to isolate them as best as possible. Thanks for all your help Tom.

Tom · Post by **Tom** » Fri Aug 19, 2005 3:13 pm

We have filtering circuits that try to minimize the noise as much as possible, but it is not 100% preventable. I apologize for any inconvenience this may have caused you.

If you have anymore questions or concerns, please feel free to post.

Best Regards,

harley7892 · Post by **harley7892** » Wed Aug 31, 2005 6:53 am

Well, after extensive testing I can report the following: I have four different display units hooked up to a p5wd2 premium ASUS board. All four units work fine, unless I connect a fan to one of the fan headers. Then I get random display corruption (about every five minutes), and once a day on average, the backlight shuts down by itself. I have many different fans, Delta, Panaflow, Thermaltake, etc,, and moved the display unit far from the fan, to minimize any noise. Tried every different USB port, with and without a powered hub. Every type of USB cable, internal and external. I have rotated each of the four units through all of the locations. I get the same results.

I have to conclude that the issue of display interference and random backlight shutdowns are the result of the unit itself when fans are connected to the high power fan headers. It may be unique to my circumstances, but the units work fine as long as I don't use the fan control circuits. Since this happens on all four units, and since they all work fine without the fan control operating, it does not appear to be a hardware problem with the displays or the motherboard.

I will keep using the units because I love what they can do. But I am going to take your advice and disconnect all the fans and move them to a fan controller. This in no way disparages your fine products. Perhaps a future model will have a more filtered power circuitry.

Tom · Post by **Tom** » Wed Aug 31, 2005 9:50 am

Hi Harley7892,

Thank you for your feedback. We appreciate any feedback from our customers. Although you may have a unique case, we will still try to improve our products in any way possible.

If you have anymore questions or concerns, please feel free to contact me.

Best Regards,