Pixels Missing on one edge of 2.8" TFT

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umop_apisdn
 
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Pixels Missing on one edge of 2.8" TFT

Post by umop_apisdn »

I just started to work with the Adafruit 2.8" TFTLCD shield. There appears to be more black space along one edge of the LCD and pixels in that area are not displayed by the example sketch.
I've attached a picture of the edge with the missing pixels.
I just downloaded and installed the library files today and they have datestamps like this:
Adadfruit_GFX = 12-7-2012
TFTLCD = 11-21-2013
TouchScreen = 2-18-2013
It reports that it is using the HX8347G LCD Driver
The program compiles and loads ok on a uno and a mega2560 but shows the same problem on both.
I'm using the 1.0.3 version of the Arduino IDE.
I did purchase this Adafruit shield through Karlsson Robotics in Florida while you were out of stock recently. Is it proper to seek help here or I should I go through Karlsson?
Thank you,
John
Attachments
Left Edge - backlight only
Left Edge - backlight only
Left Edge.jpg (301.72 KiB) Viewed 951 times
Missing Pixels
Missing Pixels
Left Clipped.jpg (293.75 KiB) Viewed 951 times

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adafruit_support_mike
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by adafruit_support_mike »

That's wierd.. looks like a pixel buffer offset more than anything specific to the display.

What do you get when you draw a 1-pixel line from coordinate (0,0) to coordinate (319, 239) and another from (0, 239) to (319, 0)? Those should run diagonally from one corner of the screen to the other. If the lines are cut off on the left but go all the way to the corners on the right, there's a mask problem. If the lines are cut off on the right and hit the edges of the screen before reaching the corners on the right, there's a buffer problem.

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umop_apisdn
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by umop_apisdn »

I got carried away with the test you asked me to run... Here is the code in the "loop":

void loop(void) {
tft.drawFastHLine(0, 0, tft.width(), BLUE );
tft.drawFastHLine(0, 60, tft.width(), RED );
tft.drawFastHLine(0, 120, tft.width(), GREEN );
tft.drawFastHLine(0, 180, tft.width(), CYAN );
tft.drawFastHLine(0, 240, tft.width(), MAGENTA );
tft.drawFastHLine(0, 300, tft.width(), YELLOW );
tft.drawFastHLine(0, 310, tft.width(), WHITE );
tft.drawFastHLine(0, 312, tft.width(), BLUE );
tft.drawFastHLine(0, 314, tft.width(), RED );
tft.drawFastHLine(0, 316, tft.width(), GREEN );
tft.drawFastHLine(0, 318, tft.width(), CYAN );
tft.drawFastHLine(0, 319, tft.width(), MAGENTA );

tft.drawFastVLine(20, 0, tft.height(), BLUE );
tft.drawFastVLine(220, 0, tft.height(), BLUE );

tft.drawLine(0, 0, 239, 319, YELLOW );
tft.drawLine( 0, 319, 239, 0, YELLOW );
delay( 5000 );
tft.fillScreen( BLACK );
delay( 500 );
}

There does appear to be a black mask between the touchscreen and the LCD panel. If I look straight down at the LCD screen the last line I can see is RED which is line 314.
If I look diagonally so I can see under the mask, the last line I can see is GREEN which is line 316.
It seems like this black mask is obstructing the LCD.
I've attached 2 pictures. One is looking straight down on the display. The other is looking as much under the mask as I can.
Also notice the 2 diagonal lines to not reach the corners of the LCD.

I hope this helps explain what I'm seeing.

Thank you,
John
Attachments
Straight Down
Straight Down
Pic2.jpg (191.5 KiB) Viewed 895 times
Diagonal
Diagonal
Pic2.jpg (341.03 KiB) Viewed 895 times

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adafruit_support_mike
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by adafruit_support_mike »

umop-apisdn wrote:I got carried away with the test you asked me to run...
Spoken like a true hacker. ;-)

The first photo shows the mask error fairly well. There's a bit of green line peeking out at the right end, but it's completely hidden on the left. Looks like the mask is either too small or was misaligned in assembly.

To do a replacement, we'll probably need to trace the chain of custody backwards.. you'll have to talk to Karlsson since you bought it from them, then Karlsson will talk to Adafruit, and Adafruit will talk to the LCD vendor. It's a bit cumbersome, but trying to skip over someone can cause an awful mess.

Feel free to reference this thread when you talk to Karlsson, and have them refer to it when they contact us.

#### EDIT ####

This thread reports the same issue, photos and all: http://forums.adafruit.com/posting.php? ... 47&t=37932

I've sent a message to Phil and Limor, and they'll get back with more information.

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umop_apisdn
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by umop_apisdn »

Well..
Karlsson Robotics sent me a replacement LCD panel. This new one has the same problem as the original. It looks like a black mask on the touch-screen covers part of the display. The other 3 edges are fine, but the narrow edge where the touch-screen connects is covered over. If the LCD was called a 240x313 pixel display I'd have no reason to complain, but something is wrong. Maybe it was a bad lot?

John

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adafruit_support_mike
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by adafruit_support_mike »

Sorry for the delay in getting back to you, I helped open a new roller coaster over the weekend.

Based on what Limor told me, this is a tough one. It's a known issue, but we're a minor customer of that vendor. We don't have the leverage to demand better QA from them.

When we do straight replacements, there's a chance that someone will get hit by the same thing twice, just like you did. We double-check the replacements we send just to be sure, but this time the reseller thing came back to bite us.

That's kind of a non-answer though, and I refuse to send you off feeling shafted because I found it easier to use weasel words than fix the problem. I don't have a good blanket solution, so let me ask you straight out:

What can I do that will make this right for you?

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umop_apisdn
 
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Re: Pixels Missing on one edge of 2.8" TFT

Post by umop_apisdn »

mstone,

I understand the QA issue and all parties concerned are at the mercy of the vendor's poor QA. As a result I have no hard feelings toward Adafruit or Karlsson Robotics. I'll return the replacement display to Karlsson and just plan my project around 314 of the 320 vertical lines. It's only about 1.5% of the display I can't see anyway. I hope you can resolve the mask issue because it seems to be a nice, well made display. The heavy PCB material gives it a good rugged feeling.
I plan to keep "making" and Adafruit seems like a good place to get materials.
Thank you for your assistance, even if there was no solution this time.
Regards,
John Nelson

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