The ‘PC040DA’ is RGB DAC (Digital to Analog Converter) used on some Taito PCBs from mid 80s like Rastan, Operation Wolf, Tokio, LSA Squad.As other similar color DAC it comes in SIL package:
But, as you can see from picture above, unlike the “big brother” ‘TC0070RGB’, you will always find three ‘PC040DA’ (one for each color) on a same PCB.Technically speaking the custom is a 5-bit DAC (6-bit actually but the least significant bit is tied to GROUND or VCC ) for a total of 15-bit of palette data received on their inputs.You can see its pinout in this snippet of Bubble Bobble schematics:
This custom has been already analized and successfully reproduced some years ago, you can read more about on this french forums :
But I decided to do my own reproduction taking inspiration from some bootleg boards where the component has been re-engineered with a simpified circuit.The prototype on breadboard worked fine:
So I developed a proper PCB:
This is the final testing on a Rastan PCB where the reproduction has replaced the original part related to RED color channel:
See you all to my next reproduction project!