Post by kahuna on Jan 27, 2020 1:11:45 GMT -7
Hi there,
Still a work in progress, but today I was able to gain momentum and make some advances
Let's try to describe the process I followed.
This is what I saw when I booted the Breadbin for the very first time:
I found this website where some of the most common failures of a C64 are listed.
It looked like there was at least one bad RAM chip. So, I went ahead and ordered a couple of them from a guy who lives in Québec.
Watched this video from Perifractic, (thanks Sir!). Problem was, I couldn't tell... out of the 8 RAM chips, which one was bad
Mmmhh, I did order an awesome Ultimate II+, I wonder if perhaps there's a way of simulating the C64 dead test cartridge, and... well, how in the world will I "insert" that considering I don't see a thing on my TV screen.
Lucky me, the Ultimate II+ supports Telnet.
So, I had a way of mounting that test cartridge, restart and yay! magic in form of white flashes happened!
Here is the video
Considering that flash pattern, the defective should be U12. Alright, let's do some piggybacking:
Nice! let's load the dead test cartridge and see what we've got now:
It looks quite similar to what it should be... (from VICE emulator)
OK progress, at that point the RAM was good, no flashes on the screen. However, it wasn't working, I had to find the culprit...
Looked at the CIA chips, one of them seemed to be connected but not placed completely flat on its socket. Let's take both out
Interesting... When I "inserted" some diagnostic cartridges I was able to read whatever was on the screen
However, nothing really happened... the system was frozen
So, what is it this time? PLA or a logic problem perhaps?
Any comments, suggestions are more than welcomed.
Thanks!
Still a work in progress, but today I was able to gain momentum and make some advances
Let's try to describe the process I followed.
This is what I saw when I booted the Breadbin for the very first time:
I found this website where some of the most common failures of a C64 are listed.
It looked like there was at least one bad RAM chip. So, I went ahead and ordered a couple of them from a guy who lives in Québec.
Watched this video from Perifractic, (thanks Sir!). Problem was, I couldn't tell... out of the 8 RAM chips, which one was bad
Mmmhh, I did order an awesome Ultimate II+, I wonder if perhaps there's a way of simulating the C64 dead test cartridge, and... well, how in the world will I "insert" that considering I don't see a thing on my TV screen.
Lucky me, the Ultimate II+ supports Telnet.
So, I had a way of mounting that test cartridge, restart and yay! magic in form of white flashes happened!
Here is the video
Considering that flash pattern, the defective should be U12. Alright, let's do some piggybacking:
Nice! let's load the dead test cartridge and see what we've got now:
It looks quite similar to what it should be... (from VICE emulator)
OK progress, at that point the RAM was good, no flashes on the screen. However, it wasn't working, I had to find the culprit...
Looked at the CIA chips, one of them seemed to be connected but not placed completely flat on its socket. Let's take both out
Interesting... When I "inserted" some diagnostic cartridges I was able to read whatever was on the screen
However, nothing really happened... the system was frozen
So, what is it this time? PLA or a logic problem perhaps?
Any comments, suggestions are more than welcomed.
Thanks!