Garbled display (seqv4)

[mongrol]

Hi folks,

After replacing the header on one of my oled displays I've found it only shows garbled text (see pic). I've reflow/soldered all connections, changed cables and ran through the testlcdpin tests which have proved positive at the oled end. Is there anything else to try or do I now have a expensive duff display?

Edited March 8, 2016 by mongrol
Might help if I attached a picture.

[latigid on]

Check the orientation/soldering of your resistor network/595. Can't see your pic btw.

[mongrol]

Thanks lat. It must be ok. This display was working just before I changed the header. I've proven both cables and the core with my other working display.

[latigid on]

If it all works with other displays/cables, then it's the display. TK could probably tell what pin is buggered from the output, but not a mere mortal such as myself. Sadly it's quite easy to cook the onboard registers, even as much as shorting pins together with a multimeter probe, experiments with 5V/3v3 fiddling, backwards cable etc. 

[Hawkeye]

Also check for a stable power supply - these Raystar OLEDs have some trouble, if there is some noise (e.g. from a cheap switching PSU) on the line. How do you power your SEQ? USB? You might change the USB-cable or the USB power supply for a test... 

Many greets,

Peter

[mongrol]

Another sympton is when powering on it stays blank. It takes a reset from either the Discovery button, or doing a "testlcdpin reset" to get it show it's gibberish. I'm going to change the header on my working OLED next. If I'm going to break both of them I might as well do it before I order new ones. :)

Edited March 8, 2016 by mongrol