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Laser Power Supply

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mechelec:
Hi,

I recently bought a secondhand power tool that has a non functioning laser.
I narrowed the problem to the power supply for the laser.
The PS has what appear to be 10 ohm resitors on the 240VAC lines.
One of them measured ~12 ohm and the other was opem circuit.
Can any one tell what the purpose of the resistors are and whether I can replace the faulty one with a normal 10 ohm resistor,

Thanks,

James

Mechatrommer:
that is a very strange power supply. i believe its have been modded.

scrat:
They're maybe there for inrush limiting, ie to limit the initial current that flows in when the rectifier's capacitor is discharged.
If you replace them with other similar value resistors (same nominal resistance and power), I see no reason why it shouldn't work.

tecman:
There would NOT be a 10 ohm resistor across the line.  As Scrat mentioned, it could be a thermistor, but that should be in series with the line, to limit inrush to the filter cap.  Usually they should be somewhat higher than 10 ohms.

paul

Mechatrommer:
and they should be in the black box in the first place.

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