Hi,
I have a GM328A that has been languishing in a drawer awaiting repair for about two years that I have only just had time to get round to this week. It initially worked fine but began to fail now and again by displaying a white screen momentarily as the encoder was pressed to start it up. Now that's all it does when the encoder is pressed. I reflowed the solder on the TFT screen's pins as well as the socket into which it plugs on the main board, which made no difference. I also flexed and tapped just about everywhere to see if I could get it to come to life again, but no joy. However, during very warm weather (over 30°C) last year I thought I would try it and it worked, once, then died again. Whether this was coincidence or the increased ambient room temperature I am not sure. I have just taken it apart now and checked all the resistances of the resistors and they all measure according to their PCB stated values. Looking at the soldering of the various components under a fairly high strength magnifying eyepiece I see nothing suspect. I know this is not unquestionable proof that there are no dry joints, but I would like to avoid a full reflow of the board if I can. I removed the ATMega328P to see what happens when the chip is removed, but the fault is the same. Would this happen anyway as the chip is not installed, or is it a clue to the stage the fault must exist in?
So that I can understand the stage at which the fault is likely to be, is anyone able to briefly describe the procedure the GM328A follows as it powers up and engages the ATMega328?
Thanks!
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