Hello Compu-Chefs and welcome back to Retro Recipes!
This time, I'm dealing with a strange fault on my Commodore Amiga 500
Which I suspect is caused by some faulty CIA chips
Very naughty CIA chips
Like these ones
They're bad..
..literally..
And they must be punished
Like being placed back, carefully, on the table here
Okay.
Welcome to Retro Recipes!
So here it is!
The Amiga 500
Otherwise known as the 'MIggy'
Was I the only one that called it Miggy, or is that a thing? I don't know..
Well, anyway, let me show you some of the weirdness that's been going on here
So let's say I load up a game such as StarGlider
Usually has that beautiful intro music..
(awesome StarGlider intro music)
(not so awesome static noise)
Not sure Rainbird would have been too happy with that!
Let's try the sequel, StarGlider 2, that should be better right?
(not music, but definitely noises)
Okay, admittedly, that's just the crack intro by UNIT A
But still definitely not right!
There's other weirdness.. if I try SysTest it actually crashes the System Test
And thinking back, I've been having these issues
Well, I've been having a lot of issues...
For about three years now
But no one really had a straightforward answer
Oh, another weird issue..
This external drive that I bought just doesn't even respond
Now, if we go back three years to before I knew how to hold a camera still
To try and get around this issue, I actually fitted a case fan
So, I thought maybe some of the chips were overheating
Cool!
Literally..
I just hooked it up here to the 5V line that the floppy disk drive uses
See
Is it hot in here??
But eventually, I knew better
And back to the present day, I'm gonna try swapping out these CIA chips
You see, the CIA is the Complex Interface Adapter
And are responsible for floppy disk control, serial ports..
You name it, really
By swapping them around, you can see if you get a different fault
Because it's the same chip in two different sockets
If one of the chips is faulty, it should cause a different fault when you place it in the other socket
At least, that's the theory
So, let's put our USB stick in the Gotek Drive
And try some StarGliding again!
Wait..
uh.. this should have.. this should have booted into the file selector now
Let's reboot and..
..try again, yet..
Okay, now I can't even get into the file selector!
Oh..
Warranty void if removed
Ah, dammit!
Was gonna send these back to Commodore, but I guess I can't now
But I do have a second set of chips in the freezer
Oh.
Yeah.. uh.. it's not a good evening here!
Now, off camera, I actually tried all four chips in both sockets in different alternations
And each time got some complete weirdness going on
Oh, Q.. join the queue.. it's a queue of Qs
Now it seems impossible that all for CIA chips are faulty
So there must be something else going on
Either way.. I'm hungry
(male nanny accent) Naughty, naughty little boys!
Nom, Nom, Nom
Now, there is something else I wanted to try
You see, a while ago, I had done this 1MG Chip-Mem Mod
And I was never really happy with how it looked
I made a bit of a mess of this and this was before I knew what I was doing, a few years ago
But it should originally look like this
You see JP2 there has these three pads and the bottom two are connected
What you do is you cut that trace between the two to disconnect them
And you add a solder blob to the upper two, like that, to connect those instead
Once you've done that, and a couple of other modifications
The board will actually see the full 1MG of Chip-Mem
The other thing you have to do is swap out the FAT AGNUS for an 8372A model
And on your expansion card, you want to disable the EXRAM, the external RAM
And this means instead of seeing this memory as Slow-RAM
It'll see it as Chip-RAM
Then you can use some of those lovely chips as extra Chip-RAM
Here's why you want to do that
You see, Chip-RAM can access the Agnus, Denise, and Paula chips for video and audio
directly without going through the CPU
which means the CPU has more time to do other things
Like..making the tea or no! Making the toast
Video Toast, of course
Wait a minute, what's going on with the upside-down, overlapping silk screening on that board?
Don't get me wrong, that's a great board, but it looks like the manufacturer had some issues
If you don't want to have those issues, (American accent) I recommend PCBWay! (laugh) Ahem.
They've been helping me out with a future video that I'm gonna be showing you soon
And they can produce these boards without silk-screening errors and actually populate the boards, too
They do the full assembly service
Now we know what PCB stands for but what does W-A-Y stand for?
I think it's what we were when we bought these Amigas as teens..
Wise And Young. (Children going "ahhh".)
So, why are you asking, do I want to undo that Chip-Mem Mod?
Well, this is the Vampire 500 V2+
And any day now, they're gonna be releasing Firmware Core Version 3
Now, this thing does some amazing things already
But with Core 3, it's gonna allow you to use some of that 128MG of on-board ram on the Vampire as Chip-RAM
Some people say 2MG, some 4MG, some even say you'll be able to use up to 64MG of Chip-RAM
Ladies and gentlemen, the Amiga 500 I mean..
The Amiga 64,000
So, I can now put this board back into stock condition
So. I'm just gonna remove this solder blob
What an 'absorbing' experience
(clears throat)
These puns are really getting on my solder wick..
Wait.. who can see the problem here?
Yeah, this middle pad has come up completely
I think I damaged it 3 years ago when I did this mod.
Oh dear.
If we follow the trace that it went to, it actually went to this other pad
If we followed the second trace that it was connected to originally
It goes to this pad
So, in theory, if I connect these two pads at this point
I won't need that other pad that has gone
So what I'm gonna do is heat up the pads
Add a little bit of solder to them
Put a generous blob of solder on the soldering iron (Mr Blobby theme tune plays)
And just touch it to those pads
If you're lucky, it'll create a bridge like this
Nice!
So, let's test the continuity
Obviously, these two pads are connected
But you can see here, it is connected to JP2 on the bottom pad
I can even actually push into the remnants of that broken pad and trace
And see that, even though, those probes aren't touching..
They still make a connection
Let's see if that made any difference!
Yes, perfect!
Oh no, wait..
Yeah, no, still just an interesting remix of these two games
Finally arriving from England, is a whole new chipset, including two CIAs
And even got got this new Commodore badge
Nice.
So, I'm gonna try two, brand new CIA chips in those slots
We'll save the other chips for dinner
Go back to the floppy connector that was in the way
Don't you hate it when your floppy gets in the way?
I do..
And it accesses!
Yes!
Take that disk out and put it back in
For the first time ever, I've got this external driver actually showing disks!
Let's try SysTest
Hey, it doesn't crash!
Good boy!
And even the CIA timer test, all the chips result OK!
(dogs barking)
Well, now the big test..
StarGlider
The dogs are excited!
(more barking)
(StarGlider intro music)
Yes!
(StarGlider music)
We're happy now!
Let's try StarGlider 2
(whispers) Yes!
(StarGlider 2 crack music)
Puppy dance!
Problem Solved! (applause)
Somehow, we actually had four faulty CIA chips!
Did you guess that's what it was?
Comment below
And Cheerio!
Ow!
(dog voice) "Now stop filming me!"
(Children booing)
(Deep pitch slow motion crashing)
Nom nom nom