Page 8 of 8

Re: A2000 Replica Build

Posted: Mon May 25, 2020 2:47 am
by grshaw
Have you seen a note or a site or anything that shows what Mods were made to the floppie209 A2000 boards? All the revisions say with mods, I am just curious to know what mods they made beyond what is in the release notes. I know they added a diode and coin cell footprint to 1.8.5. But not sure what else they fixed from the 6.2 Base.
I haven't seen anything myself. It may be in the history of the GitHub project perhaps?
How is your system running? I hope it is still going strong.
It's been 100% stable. Thanks for asking. I am really happy with it. I have seen one annoying issue though. Jumper J300 allows one to switch the source of the Tick Signal. You can select either the PSU or Agnus. My system is 100% reliable with this jumper selecting the PSU as the Tick source. However, it will not boot if I select Agnus. Kind of annoying for me specifically, because it means that Hacktrick 60Hz does not work. I know that this should work on an ECS 8372A Agnus like the one I have, so scratching my head on that one at the moment. Any ideas welcome.

Re: A2000 Replica Build

Posted: Thu May 28, 2020 8:37 am
by Zippy Zapp
Glad it is working stable. I have no idea why the Tick jumper wouldn't work correctly. If I had to guess I would say check the pins on the Agnus or the socket, especially pin 79 and everything in between that jumper. Not sure what would cause that. I assume you have an original A2000 PSU?

You are correct the 8372A Agnus is both NTSC and PAL, unlike the previous or later versions that had specific NTSC and PAL versions. I'll have to read about the HackTrick 60hz. I am an NTSC user so I am usually always set to NTSC 60hz. The only time I typically use PAL is for Euro demos that don't run quite right on an NTSC then I use my A1200 for those since it is easy to switch from NTSC to PAL.

Re: A2000 Replica Build

Posted: Sun May 31, 2020 2:12 am
by grshaw
"I assume you have an original A2000 PSU?"

Yes, I do. However, I have noticed that the voltage on the 5V rail is a bit on the high side. I measure 5.6 -> 5.7 V with my multimeter. I wonder if this is the cause of the issue?

Re: A2000 Replica Build

Posted: Sun May 31, 2020 8:40 am
by Zippy Zapp
grshaw wrote:
Sun May 31, 2020 2:12 am
"I assume you have an original A2000 PSU?"

Yes, I do. However, I have noticed that the voltage on the 5V rail is a bit on the high side. I measure 5.6 -> 5.7 V with my multimeter. I wonder if this is the cause of the issue?
Yeah that sounds high to me. I have not opened my PSU in ages so I don't remember if there is a voltage pot to adjust the 5v/12v rail. Worth a look though because I know Commodore had pots on some of the C128/C64 PSUs.