I think have mentioned before that I have special service jig that allows me to test every single LCD before posting it with the kit. It is very useful idea, as it saves money and hassle in the long run.
The usual QC fail on every batch i get is in the range of 10-20 %. And the most common fault is the famous ‘White Screen’ problem. I haven’t done any detailed analysis, but i would say is either badly soldered flat cable/mode jumpers or simply faulty controller chip.
But testing my latest batch i got more than 55% failed LCDs. And the ‘fault’ was not the usual ‘White Screen’ but something i call ‘Broken TV’, something you would get on old school analogue TV without an antenna connected.
It was really concerning, so after speaking with the manufacturer, it would seem there are four different revisions of the ILI9325 controller chip, named by them as A,B,C and D. There is a differences between them, not a detailed list of those, but one important thing would be the maximum communication speed. It would appear that version A is the slowest (not being able to handle higher clocks) and D is the fastest.
So using the 0.219.26.4 version of the source code and latest driver source code for the controller from the manufacturer i was able to make those LCDs, that have the new revision controllers work.