EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: rh100605 on October 11, 2023, 11:43:01 am
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The OLED display on the Ruark R1 Mk3 dims with age and can suffer from screen "burn" if left showing the same information, such as the clock, for weeks.
This post describes replacing the display with a low cost 2.4 inch 128*64 22 pin SPI OLED Display using the SSD1309 controller and finding the cause of control button function failure.
The display brightness is controlled by the DAB module changing the reference to an adjustable 1117 voltage regulator that supplies the OLED working voltage at between 12 and 6 volts.
Apart from the screen dimming the display would power up and show the time as 00:00 and then freeze at the next item.
I first suspected the corruption of the Flash memory on the DAB module which I had a working image for.
See my other posts to download the working binary image for the Ruark R1 Mk3.
However on power up with the new working code image the screen was still dim and the screen froze at a different point!
I then started checking all the power rails. The 7.5volts to the PT2314E audio chip was at 0.66volts ( resistance to ground was 1.4 ohms!) Using a microscope I could see a burn mark in the centre of the PT2314E package so I removed it and checked again.
Still only 0.66 volts on the supply line.
I assume the the DAB module code froze whenever it had to talk to the I2C bus which the PT2314E was holding down.
The adjustable LM1117 regulator supplying the 7.5 volts was also faulty. Replacing it restored 7.5 volts and replacing the PT2314E restored the radio function.
The dim display remained. So just worn out like the OLED display in the Ruark 4i Mk3 and many Pure Evoke radios,
EBay has listings for very expensive OLED replacement displays specifically for the Ruark R1 Mk3.
However other 2.4 inch 128x64 OLED displays are listed ("2.42 inch OLED Display Plug in 23 pin SPI Dot SSD1309 128*64 / 1.54" 24 Pin New")
These use the SSD1309 controller, come in three different colours (White-Used by Ruark, Green and Yellow) and are 24 pin (not 23) and work perfectly in the Ruark R1 Mk3 at less than half the price !
The original display is held onto a PCB by two double sided sticky foam pads which I had to cut to remove. I used Double sided tape to reinstall.
The ZIF( Zero insertion Force) socket has a bar that has to be pulled out by a few mm to allow the flex cable to be removed.
Do NOT pull the ZIF socket bar right out, it will break and the entire socket will need replacing.
Happy fixing