red 1.2" 4-Digit 7-Segment Display w/I2C Backpack

[roikr]

connecting the display to rpi is not working properly:


1. when connecting VCC and V_IO to rpi 3.3v I get very dimmed display (dimmed digits !, colons are very bright)
2. when connecting VCC to rpi 5v and V_IO to rpi 3.3v I get no address (i2cdetect -y 1)

so I tried to connect V_IO to rpi 5v - got address but when I connected also VCC to 5v - the address gone.

what is going on ?
how can I get bright digits with rpi ?

10x,
Roee

[adafruit_support_bill]

Please post photos showing your soldering and connections to the display.

[roikr]

connecting only V_IO to pi 3v (brown wire) - communication with dimmed light

IMG_1081.JPG (778.64 KiB) Viewed 457 times

disconnecting V_IO and connecting V_CC to pi 5v (red wire) - no communication but bright light

IMG_1080.JPG (891.91 KiB) Viewed 457 times

another strange behaviour, the backpack draw power also from scl and sda (if I disconnect V_CC and V_IO I still get light)

[adafruit_support_bill]

We need to see all the soldering on the board. Please post photos of the back of the board also.

Where do all the other wires in the photo go? You can't drive the display making only 1 connection at a time. All 5 wires are required to drive the display. Applying power to a circuit without a connected ground wire can damage the circuit.

GND - GND
VCC - 5v.
VIO - 3.3v
C - SCL
D - SDA

[roikr]

IMG_1085.JPG (712.06 KiB) Viewed 434 times

IMG_1086.JPG (863.48 KiB) Viewed 434 times

when I disconnected V_CC from the pi and measure its voltage, I got 2.8v
disconnecting V_IO from the pi and and test it, give 3.3v (when V_CC is connected)
is that ok ?

[adafruit_support_bill]

when I disconnected V_CC from the pi and measure its voltage, I got 2.8v

VCC is your main power to the board. You are probably just seeing some of the V_IO voltage leaking back through the circuit.

disconnecting V_IO from the pi and and test it, give 3.3v (when V_CC is connected)
is that ok ?

That sounds right.

Your photos don't show your soldering to the display itself. What does the display do when fully wired?

[roikr]

my soldering...

IMG_1087.JPG (727.54 KiB) Viewed 427 times

when fully wired, i2cdetect -y 1 doesn't display the address.

[adafruit_support_bill]

Please contact [email protected] with a link to this thread and request a replacement backpack & display.