Hi. Please upload a picture with marked points, where did you measure, describe what you did in detail. Maybe i can help… I don't have this board anymore, since it was repaired and returned to the customer....

Hi, you cannot use BC807, as its specs are worse than those of 2SB1197A (Apparently, there is some current flowing through the Collector). You could try, but the longevity of the repair is then at risk.
BC817 most probably is an adequate replacement for MMBTA13LT1G (if gain is not important, but you could only confirm this by reverse engineering the circuit around it, or TRY ), see below the spec comparison.



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