What happens to the polarised cap C11 doesn't it explode on negative half cycles?This is clever. D7 D9 C11 C21. I was thinking "this must be an error". Then I simmed it.
Previously: Kuei Yang Wang
There's nothing to limit the current through C11 and D7 especially at turn on, the inrush will be high.
Incorrect. The capacitors ESR and the Diode's internal resistance will. The capacitors originally used had significant ESR. Remember, this is a 1980's design.
In addition, this is powered from a mains transformer also loaded by a rectifier and large PSU capacitors, which will draw down initial voltage delivered from the winding.,
When I simulated it C11 exploded.
You did not simulate a sufficiently large number of variables in the system and were misled by a bad simulation.
Adding a series 10ohm with the C11 cap limited the inrush and stopped the cap from blowing up
It will not do harm but is not needed.