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Old 06-03-2019, 12:39 PM   #1561
PeteS in CA
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Default Re: the gutless, bloated, and fried power supply hall of shame

ae7oo, if the TL494 clone PWM is on the secondary side then no feedback optocoupler or feedback transformer is needed. The pulse width modulation is done by the PWM IC, which drives the switch transistors.

For having been built in the second half of 2000, that 1A 5VSB is pretty wimpy. The 2SC3866 switch transistor is probably for the 5VSB, while the 2SC4106 switch transistors are the main inverter, probably half bridge. Everything about it screams noisy gutless wonder. Trying to draw 250W continuous from it probably would have resulted in a dramatic event in a matter of minutes or less.
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