Hi Al,
Are these voltages at J1 of A3?
pin 15 at 4.68V is interesting as you are measuring 4.96V at C101 which is the same net. Perhaps average value is looking OK but there is large ripple? Or there is large IR drop between two grounds you used for two measurements?
Pin 17 and and 18 are shorted and should be -15V, you measured 4.28V at one and +0.65V in the other.
It is likely the pin numbering is different than what you assumed.
Ozan
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On Fri, Oct 6, 2023 at 07:35 AM, @GP53 wrote:
Ozan,
Voltage at C101 is 4.96 Vdc and is the same at R101. R107 is good at 14.7k.
At the left side of R101 there is no wave form at all. At J1(ribbon cable), pin 15?
is +4.68v, at 17 it’s +4.28v, ?and at 18 it’s +0.65v. Will check power supply ripple
tonight.
Al
