I have just assembled a DSO138 board, though I have separated out the slide switches and Tact switches for fitting into a case. On powering up I firstly checked TP22 which gave a correct 3.3 V, so I shorted JP4. I plugged in the LCD board which remained blank (no back lighting or anything) I unplugged the LCD board and entered test mode, which resulted in the LED slow blinking
I have a few strange results when checking out some of the voltage reference points. Most seem to be more or less OK (the supply voltage is 8.8 V) The most odd result is that on J1 there is a reading of 7.1 v between pins 16 and 18.
As an aside, I am using rotary selector switches instead of the slide switches and so the switch cases are not connected to the PCB. I could not see any need for this on the circuit diagram, but maybe it is required.
Any advice would be welcomed
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