Very poor lightning on CFAH2002-A TMC JP


New member
Hi, Sorry if my English is a bit bad (French I am):

Here's the prob: I've bought recently this display with some other friends from France.

Everything seems to works fine (I get messages; etc...) except for reading on the LCD ! ! !

Even in the dark, it is really hard to see what's on the screen!!:mad:

Simple: The backlight is on (the LED on the right are "powered") but the screen is not flashy at all.
Same problem for the characters displayed, I need good eyes to see what's on.

The adjustable resistance is at its max; and the voltage is 3.5V between pin 15-16 for the backlight (since there is a 150 Ohm resistance). Even with 5V (max from the PC), the color is turning a bad blue-green not beautful at all!

What is the problem with my LCD?. I compared with a LCD (the same model from the same order) that a friend of mine has, and his one is OK:rolleyes:

Is there any solution??

Is it possible (in case nothing can be done) to send it back to you for another one completely operational ?

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CF Tech

I am sorry that there is trouble with the display. There is often a lot of problem when someone attempts to connect a parallel LCD to a PC's parallel port. The CFAH* series displays are intended to be used as a component and to be integrated into a larger product. They are not meant to be an end product alone. THis is why we do not recommend connecting them to a PC's parallel port. Instead we recommend our serial displays which can be connected very easily with no soldeing. We test all of our displays at the factory, and we know it was in working condition when it left here.

I think that this display has had the backlight damaged. If you put +5v or +12v across the backlight for even 1/10 of a second, this may enough to permanently damage the LEDs. What you are describing is very typical of an LED that has had excessive current driven through it. This type of failure is pretty much impossible to have happen in transit.

I think there is really no reason to send it back, since there is no way to fix the LEDs once they have been damaged.

I will send you an e-mail.