John_Matthews
New member
So, this was a working HM - and still is aside from the LCD. The left and half of the display seems not to be working and the letters are garbled occasionally and offset to the right half of the display. See the image below:
This was working originally, and I suspected dry joints so have re-soldered all the LCD connections and the shift-register chip. No real change. I've tested continuity between the shift-register and the LCD pins - all good. I've also tested for shorts between the LCD line pins - all good.
I've measured the voltages on the legs of the shift register that drive the LCD and can see bouncing between 0-3.3V (well, seeing that on a slow response voltmeter is tricky but I can see changes in voltage).
Any more pointers?
Thanks,
John
This was working originally, and I suspected dry joints so have re-soldered all the LCD connections and the shift-register chip. No real change. I've tested continuity between the shift-register and the LCD pins - all good. I've also tested for shorts between the LCD line pins - all good.
I've measured the voltages on the legs of the shift register that drive the LCD and can see bouncing between 0-3.3V (well, seeing that on a slow response voltmeter is tricky but I can see changes in voltage).
Any more pointers?
Thanks,
John