OK - interesting feedback. I will look into the price of 7 segment LEDs that are as close as I can find to the originals. I do remember last China trip I tried to find them with a 'comma' but they simply are not made. Pinled have theirs specially made. I hate to think of the min order qtys for that...............

The rest of the parts are all very VERY common and dirt cheap so the main cost would be the displays and the PCB's.

I would also like to take some accurate measurements to determine exactly how much current they would draw from the 5 volt rail and perhaps build something into the replacement boards that generated the 5 volts to run them to ease the load on the original power supply??

Any other interest in this as a project?

PS - I will add that the chip I have used - the BCD decoder - does NOT provide a 'tail' on the 6 or the 9 (you can compare in the youtube video with the original display) - I don't know how important this would be for people???