Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

[SOLVED] Nokia5110 display backlight is always on?

Status
Not open for further replies.

kgavionics

Full Member level 3
Joined
Jun 12, 2012
Messages
166
Helped
7
Reputation
14
Reaction score
11
Trophy points
1,298
Location
Alberta.Canada
Activity points
2,467
Hello, I bought a few 5110 on eBay, and they're working ok , except they have weird issues. Firstly, in accordance with the data sheet (PDC8544 chip) these displays are 3.3V, but mine they only work with 5v. Secondly, the Backlight is always on whether I hook the pin to 3.3V via a 330 ohm resistor, tie it to the ground or leave it floating, the backlight stays on.
Does someone know what could be the problem?
Thanks in advance
 

Attachments

  • nokia5110-2.jpg
    nokia5110-2.jpg
    376.1 KB · Views: 93

Hi
I have used 5110 modules and didnot face this issue. Some of the modules have an SMD 1k resistor soldered off the shelf. Please check the PCB track of BL pin on backside of module. You might need to solder-out that resistor.

Also I think backlight is due to smd leds on pcb. you might want to carefully remove lcd to see leds soldered on to display board.
 

    kgavionics

    Points: 2
    Helpful Answer Positive Rating
Hi
I have used 5110 modules and didnot face this issue. Some of the modules have an SMD 1k resistor soldered off the shelf. Please check the PCB track of BL pin on backside of module. You might need to solder-out that resistor.

Also I think backlight is due to smd leds on pcb. you might want to carefully remove lcd to see leds soldered on to display board.
Thank you for the heads-up
After doing some measurement, I found this how the backlight is wired on my display. (see attached schematic)
 

Attachments

  • dopus_UD3tjL28M7.png
    dopus_UD3tjL28M7.png
    21.9 KB · Views: 97

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top