crystalcontrol and beeping

I have a 624 running in win2k and when I try to add my lcd profile at the proper baud rate and everything then the screen fills up (solid black) and I get a constant beep noise on my speakers. It works fine with wintest. It seems to be the program. I'm using another from 2morrow.com and it works fine.

Have you checked the contrast? in CrystalControl?

Does CrystalControl tell you anything?

It seems unlikely that this is the cuase since the beeping is present.

Is the beeping coming from the PC Speaker, or the sound card?

Not the contrast. Beeping is coming from the speaker, not the sound card. Hardcore interference I guess. But I don't get this interference with wintest or anyother software. And no crystalcontrol doesn't say a thing. No error messages or anything. It thinks everything is fine.

And simply switching software solves the problem, you don't touch any hardware?

When is the beeping occuring, I assume during the operating system and NOT during boot up, right?

BTW, I don't know of other languages, but I think only the motherboard as access to the PC speaker, all else have to use the sound card. I'm probably wrong on that but, thats what I thought.

If you have a second com port, you might want to try a different comport.

Is the computer a generic computer, (You built, or someone else) or is it a major brand like Dell, Compaq, etc?

Sorry, not the motherboard speaker, my stereo speakers are beeping. Hence interference. BTW this noise is LOUD not a minor interference, MAJOR interference. It happens when I load the LCD module in crystalcontrol and not with any other program. No problems during boot up. I built the computer myself. I also get the same problem on com port 2.
Can any staff help too?

Ok, I "fixed" the problem. By putting the backlight up to 100% I no longer get interference. ??? The tone of the beep changes with the backlight %. Now I feel its a hardware design flaw. I do have an older module. I think wintest defaults at 100% as does the program from 2morrow so hence no problem with them.

The backlight is controlled by PWM (Pulse Width Modulation), which means it is switched on and off faster than you can see.

If there is noise in your speakers, then the electrical switching noise of the backlight is somehow coupling into the input of the sound card.

Please try these items:

* Check the connections from the power supply to the LCD.

* If there is an unused input to the sound card (Mic or Line In) set it to 0 with the "recording" section of the volume control.

* Make sure your speakers and any thing connected to the sound card is correctly hooked up.

Or just leave the backlight at 0% or 100% which will turn the PWM off.