24V to 12V conversion in a gas detector

Hi,
I have a gas detector which is designed to be powered by 12v AC or DC, and I want it to run it on 24v DC. After the power terminals, the is a bridge rectifier chip - DB104 - as here - TAIWAN SEMICONDUCTOR|DB104G|BRIDGE RECTIFIER, 1A, 400V | Farnell United Kingdom
The output then goes to an empty space on the pcb marked IC4. The space has 3 holes in a line. Hole 1 is connected to the DB104 output, hole 2 is grounded, and hole 3 is connected to the rest of the circuitry. There is a jumper across hole 1 and 3. So at the moment 12 v output from DB104 goes straight across to the main electronics.

I am thinking that the 3 holes are spaced to accept a T0-220 voltage regulator and that I could fit a 12v 1A regulator to regulate incoming 24v down to 12v. DB 104 can cope with 24v.

Am I correct???

Thanks.

I don't know because you haven't posted the schematic.

If the detector is designed to be powered from AC or DC then it already has a bridge rectifier so there's no need to add one.

The peak voltage of 12VAC is 17V so you could just as easily use a 15V regulator as a 12V regulator, it depends on the minimum input voltage.