If I then increase the voltage it starts clicking slowly and the scope shows shorts on the output caps (C144).
I have now replaced C132 with a new part, it has a slightly higher value (new: 80nF, old: 2.2nF). I tried running it directly on mains now (~230V) and the main cap charged to just above 300V, the gate pin on TS132 is now ~1.5V.Below C132 you drew a red ground icon. Although it makes sense for a ground connection to be there, C132 absolutely must be healthy not leaky. There's a chance it provides a snubber effect, in order to substitute for the DCR arrangement D133 C133 R133 which is often installed as a snubbing network (but which you marked through with a red X which implies it's absent).
A flyback primary (T101) commonly generates high voltage spikes at shutoff. To absorb these spikes a snubber is normally installed. However if snubbing is inadequate then the spikes can destroy neighboring components. Example, C132 or TS132 where you reported abnormal volt readings.
This makes a reason to examine C132 because if it's not healthy it can cause problems especially as you increase power. C132 must maintain a proper Farad value, tolerance to high voltage, with no leakage meaning its DC ohm reading should be infinite.
And it may help if you install D133 C133 R133 as seen in your schematic as well as numerous other flyback schematics.
I tried running it directly on mains now (~230V) and the main cap charged to just above 300V.
the gate pin on TS132 is now ~1.5V
Seems like I forgot to include that part,Do you still get the clicking noise reported in your initial post?
If you made progress then it's time to check your output voltages. If they are not normal then the supply isn't fixed, and you should avoid running it at full house voltage longer than the time it takes to test voltages.
The schematic shows -4.1. Since that section of circuitry has high supply voltage, it's hard to be sure whether the readings of low voltage are an average due to switching on-&-off, and whether 1.5V is close enough to call it normal or whether it ought to be closer to -4.1V.
P75NF75 is listed as a 75V n-channel mosfet I don't think that would work very well for a circuit switching 300V.What did you replace TS132 with ?. The part number is 6190002200 and the transistor is labelled K561-2 8843 found NTE2315 as matching part but unavailable in UK. Found P75NF75 but not sure its suitable. Thanks for any help.
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