I see where it says live ground with a white arrow head. I see where it says DGND with a white arrow head. I see several black arrow heads , and I see several slashes under a line that looks like a ground of some kind.
Are the voltages past the bridge rectifier DC? I measure 163 VDC across C34.
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Are the voltages past the bridge rectifier DC? I measure 163 VDC across C34.
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The green wire attaches to chassis ground. Live ground is not actually a ground, it is a floating reference point for the line connected supply. Transformer TX1 separates the line (hot) side of the unit from the low voltage side on the right of the schematic. Everything to the left of TX1 is deadly, use extreme caution. The right side is safer but the power supply puts out 48 volts and this is still in the range of deadly voltages. (i.e. voltages that can supply sufficient current to kill you. It is the current that kills and it only takes 100 to 200 milliamps.)
Without an oscilloscope you will have a had time troubleshooting this power supply. This is a switch mode power supply and a meter will not give much information. However, there are a couple of things you can check if you do so safely.
Here is a brief description of how the circuit works and what can be tested with a voltmeter:
Of course you know the purpose of the bridge rectifier and that you can measure the high voltage DC across C34. Since you have 116 volts input, the voltage across C34 should be 116 x 1.41 = 164 volts. (RMS x the square root of 2) The negative side of C34 is "live" ground. If you had a scope you would see it with a negative half cycle waveform at the line frequency. So "live" ground is very hot! The positive side of C34 is labeled +V1 and is also very hot.
If you have a good DC voltage of about 160 to 170 volts across C34 then you can proceed to the next step. IC3 is the heart of the power supply, it was manufactured by a company called Unitrode. Unitrode was bought by Texas Instruments and this particular part is no longer made. Here is how it works:
At start up a small amount of current flows through R24 to supply IC3. When IC3 gets sufficient power it will start oscillation on pin 4 which connects to the gate of TR2. TR2 supplies a little current through the primary winding of TX1. The secondary winding on terminals 3 and 14 supplies some small current through R30, D10 to TR4. TR4 is a linear regulator, the base is set to 13 volts (relative to live gnd) by R31 and zener diode ZD3. Due to the voltage drops across the base-emitter of TR4 and D11, the voltage supplied to pin 3 of IC3 will be about 11 volts. (referenced to live gnd) So the result is that R24 gives it a little kick but the actual voltage supply to IC3 is coming from the switching of the power circuit.
With a multimeter you can measure some of the DC voltages but you won't be able to see the actual switching. If the voltages on the primary side appear OK then check the secondaries, there are four outputs; +17, -17, 14 and 48 volts. In fact, check these first, it is a lot safer.