Author Topic: NHD-4.3-480272EF-ASXN#-T with NHD-4.3- 480272MF-22 controller board  (Read 1040 times)

bvbor

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The stated above configuration of hardware works fine other than it  starts flickering after a while. When the flickering starts, the temperature measured in vicinity of the display assembly is around 40 degree C. The flickering stops when display is cooled down to 36 degree C. Obviously, these temperatures are well below 70 degree specified for both NHD modules. Any suggestions? Thanks.

Ted_M

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Re: NHD-4.3-480272EF-ASXN#-T with NHD-4.3- 480272MF-22 controller board
« Reply #1 on: February 04, 2019, 10:16:40 AM »
Sorry to hear you are have this issue.   Is the issue with the backlight flickering or only the image displayed on the TFT?
The backlight requires 40mA at 25.6V for full brightness.  Please check the current draw of the LED backlight to see if it is within specifications.
It is also possible that there is a dirty or loose FFC cable connection which may be contributing to this flicker effect.
Please double check the cables and Molex connections are clean and solid.  Also, please check the power source or try a different power supply for the display in case there is a noise issue on the supply voltage.

If these suggestions do not clear the issue, then please email us at techsupport@newhavendisplay.com to request an RMA

Best Regards,

bvbor

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Re: NHD-4.3-480272EF-ASXN#-T with NHD-4.3- 480272MF-22 controller board
« Reply #2 on: June 24, 2019, 09:52:02 AM »
I am sorry, but unfortunately I have to return to this issue. I will also copy and paste this as a new topic, in case nobody pays attention to something that started that far in the past. OK, now we have built a small quantity of devices using your NHD-4.3-480272EF-ASXN#-T with NHD-4.3- 480272MF-22 controller board. Some of them sometimes flicker, not all and not all the time. The flicker always stops when we cool down the units. However, we have seen flicker even on relatively cool units.
The voltage on J2:2 and J1:4 is 3.3V, the back-light voltage on J1:2 is 21.35 V. We have seen occasional bursts of noise on the back-light voltage that last couple hundred milliseconds. These bursts coincide with the display flicker and don't look synchronized to any activity on digital interface lines. I captured few oscilloscope screens and can send it for you to analyze.
I even tried to solder a large tantalum capacitor on the Back-light voltage output on the controller board and it seems to help with the problem. Unfortunately, the biggest capacitor that fits nicely is only 15 uF which worked in most cases but not all.
Clearly, we need help with either suggestions how to deal with the issue or at the very least a schematic of your controller board.

Ted_M

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Re: NHD-4.3-480272EF-ASXN#-T with NHD-4.3- 480272MF-22 controller board
« Reply #3 on: June 24, 2019, 10:11:31 AM »
Sorry to hear this is still an issue.  Please email me at tmellenthin@newhavendisplay.com and I will assist you in resolving this issue.

Best Regards,

 

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