Quote:
Originally Posted by shaf
Let me recheck the schematics and see what i can find. I doubt it would be a degauss function because none of the other Commodore monitors have this feature. And it usually requires a manual reallignment.
|
Every single color CRT ever made has a degauss function and degaussing coil.
In most cases, they were simply a loop of wire around the front of the tube, connected in series with a PTC resistor, powered by the incoming AC power.
When you turn on the CRT and the PTC is cold, it allows a LOT of current to pass through the degaussing coil. This heats up the PTC, which raises its resistance and reduces the current through the degaussing coil, until the current almost completely dies off - this degausses the tube.
If you turn the unit off, then immediately back on, the PTC doesn't have any time to cool down, so it doesn't degauss the tube again. The PTC must cool down before another degaussing cycle will occur.
If you leave the unit on for months at a time, you will see the colors slowly start to get corrupted as the tube gets magnetized by the earth's magnetic field. This is why every tube has the degaussing circuit.