On Fri, Oct 21, 2022 at 08:47 AM, Rogerio O wrote:
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However, the resistance of the +12V to ground was only 18R in contrast of the -12V to ground that was 2.9K.
The +12V regulator is managing to keep the volatge at the nominal voltage, but I could not identify any section of the main board circuit that would explain this low value other than a leaky C297, but this cap has been replaced when I started the repair job.
So my questions are:
1 - Is this low resistance "normal"??
2 - Is it possible that this low resistance is causing the circuit to clip, despite the +12V rail voltage value is correct ?
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Hi Roger,
You may be seeing semiconductor junctions turning on. Does switching polarity of the ohm-meter leads change the measurement? Does changing the range of the ohm-meter change the measurement?
Observing ?+12V on channel 2 while looking at ramp signal on channel 1 can tell if supply sinking is the issue although it looks like clamping is happening at negative side.
Ozan
