Recently I found a CDI 220/00 with Mini MMC mainboard. It’s a heavy and bulky unit that contains lot of PCBs, wires, screws and metal parts. It’s one of the first consumer CD-i players, later models have all components on one single mainboard (Mono).

Doing a 60 Hz modification is very easy, just move the solder blob from PAL to NTSC. Or install a switch at the NTSC, middle and PAL points.

However, replacing the TimeKeeper chip is rather complicated as you have to disassemble half of unit to reach the mainboard.
Note: All screws are Torqx T8.

First remove 5 screws with washers to open the top case, then the back bezel (3 screws) and DVC door.

Slide out the DVC base und the two plastic guides at each side.

A close-up view of the PCB that holds the DVC:

At the back of this PCB is the working area, PAL/NTSC on the left and TimeKeeper chip on the right (and some dust). Don’t bother unscrewing the PCB, just unscrew the piece of metal (2 screws) and put the whole thing over to the CD side.

Now it’s time to lift the mainboard (3 screws):

Remove the TimeKeeper chip from the marked area.

This is the mainboard back in place. The solder blob has been temporarily moved from PAL to NTSC to test the image stability and a socket with a new NVRAM chip (DS1643, more reliable) has been installed.

There is a lot of space in the DVC cage, enough to install the 50/60 Hz switch. (Optionally you can hide the switch behind the front panel door)

Then check if the switch works (never switch when the unit is turned on!) and if your NVRAM is still good. The put everything back in reverse order.

Switch hidden behind the DVC door:

Done!

We haven’t seen all PCBs yet: