What RTC chip did you use and is your clock working correctly? I noticed in your latest picture you don't have the clock crystal or the VC800 trimmer capacitor installed.
At the time of the previous photo in this thread, the Real Time Clock wasn't working. I have since got it working using a RTC-72421B from Epson https://www.mouser.co.uk/ProductDetail/ ... ApgA%3D%3D
I have been reading the datasheets to the various RTC chips and what I don't understand is why the crystal and trimmer cap were necessary. According to the Oki and Epson RTC datasheets all the RTCs that were used have a built in clock crystal. And most use two 22pf caps for the clock.
You are absolutely correct. If you are using a modern RTC chip, then the trimmer capacitor and the crystal are completely surplus to requirements. They were required back in the 80's and they have not been removed from the PCB.
The Oki MSM6242 chip (Original Spec chip from the schematics from Commodore) show that 16,17 to be XT and that a Crystal should be connected to these pins. I wish I completely understood this stuff because the chip datasheet also states that a crystal is built-in to the RTC Chip. Confused.
Definitely, the thing to go for is the Epson chip above and leave the trimmer capacitor and the crystal in VC800 and Y800 respectively unpopulated. The Epson chip is a pin for pin replacement for the 6242 but with those components included inside the package.
I tried to purchase new 23 pin motherboard Dsubs from iComp, as well as a couple other items and they are charging 47 Euros for shipping via DHL.
Yeah - that sounds like daylight robbery.
I think the Vidiot is the same on the A500.
Yes it is. I also used a Video Hybrid from an A500 and it worked absolutely fine.