The schematic of the IIci start-up circuit, from Gamba's site:
Unlike the II and IIx, it doesn't seem to have a thermal sensor anywhere, which could cause the symptoms you mention... anyway, it's a pretty simple circuit to troubleshoot. The ICs are SMT, but 14-pin only :b&w:
You did change all capacitors on the board, right? Particularly C11 and the associated R33 resistor -- if it looses its charge somehow, computer will shutdown sooner or later! Check the area around these and, just in case, the solder joints of the power connector on the board.
Unlike the II and IIx, it doesn't seem to have a thermal sensor anywhere, which could cause the symptoms you mention... anyway, it's a pretty simple circuit to troubleshoot. The ICs are SMT, but 14-pin only :b&w:
You did change all capacitors on the board, right? Particularly C11 and the associated R33 resistor -- if it looses its charge somehow, computer will shutdown sooner or later! Check the area around these and, just in case, the solder joints of the power connector on the board.