Hi.
The "Usual" scheme, is for both the bulk storage caps to be wired in series at all times, with balancing resistors across each of them...? (To compensate for slight variations in leakage of each cap', and to ensure they discharge safely when the incoming power is turned off.)
The output of the full wave bridge goes to the +ve of the top, and -ve of the bottom cap at all times.
For 110V input, the common is connected to one of the incoming AC input lines, forming a voltage doubler. (With two diodes just working, and the other two reverse biased all the time.)
For 220V input, the common is NOT connected to anything, so the full wave bridge acts as such in the usual manor, all four diodes working as a bridge..
The advantage is that both cap's see the same voltage, individually, and as a combination.
The disadvantage, is sometimes, kit can be powered from a 220V line, while the switch is configured for 110V!
If ever needed, both cap's should be replaced as a pair, with identical parts* of the same batch and date code.
(* Not necessarily "Identical" to the original parts, just so long as the replacements are identical with each other!)
Do also check the balancing resistors have not changed value or one has gone open.? That can be "Very Bad" for one or other of those caps, even brand new parts!)
Take care.
Dave 'KBV.
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