22-01-2016, 04:37 PM
As well as capacitors, be suspicious of any high value film resistors on the primary side. It's common to use 100-300k to drop the 325V DC down to provide the start-up current to the controller. Or about half that if there are two capacitors in series for 120/240V switching... These resistors gradually fail high because of voltage stress. Metal glaze replacements are a lot more reliable than metal/carbon film types. But in extremes, several smaller ones in series reduces the voltage stress...
And when it's apart, be aware that if it didn't start last time it was tried, the main smoother capacitor(s) could be charged. Sometimes, bleed resistors might be fitted, but these usually fail in exactly the same way as the start-up resistor!
And when it's apart, be aware that if it didn't start last time it was tried, the main smoother capacitor(s) could be charged. Sometimes, bleed resistors might be fitted, but these usually fail in exactly the same way as the start-up resistor!
