In a previous video, I reviewed the Mini-PET 40/80D. And while I did build a new keyboard for
it, I didn’t really have any good way to mount it together. And at the end of the video I said this:
One of the things I would like to do is make a case for this version as well.
If somebody out there knows how to work with acrylic, like maybe laser-cut acrylic or
something like that, or has a 3D printer that is big enough that you could make the entire case.
If that’s you then get in contact with me by email.
If you like to see your work featured in a future video, and we’ll see what we collaborate on that.
I had many very generous offers for this type of thing, But
I decided to go with Nick with Dogfish Dimensional Concepts. I sent him the
motherboard and the keyboard for him to measure. And he began to design a model in solid works,
as you can see here. Once the model was done, the acrylic was laser cut.
Then it was just a matter of gluing all of the pieces together.
There was some minor touch up work to smooth out some rough edges.
And then he assembled the board and keyboard into the unit to make sure everything fit right.
And well, here it is. This is a beautiful piece of art here!
This actually turned out better than I could have ever imagined. Now,
as much as I want to see it work, I can’t actually use it yet because nothing is connected inside.
So, what I’m going to do is go ahead and take it apart. This little top cover part comes off,
which will give access to much of the board. Now, one problem I’m concerned about is the
keyboard wires as they are currently, probably won’t fit. I don’t think there’s enough vertical
room for the connectors. Well, the only way to find out is to take the keyboard off.
Notice that Nick designed in some very clever support structures for the keyboard.
Anyway, let’s test fit the ribbon cable.
OK, here goes. And pretty much like I feared, the keyboard won’t seat down like this.
OK, so let me tell you a little bit about what I’m going to be doing. So, I think I’m going to
desolder this pin header down here completely. And I’m just going to solder wires directly to
the holes. Now it will still have the female pin header connectors on the other side,
so the keyboard will still be able to be disconnected. It’s just that the wires will be
permanently connected to the motherboard. There’s also a power port over here and he has made space
for it, but I don’t really like the power cord hanging out of the side and not only that,
I don’t like the fact that there’s no power switch on here. So I think what I’m going to do
is use the original power input connector for the PET that he’s also provided over here and I’m
going to desolder this connector and then I’m going to put me a barrel jack back here somewhere.
I think I’m also going to desolder these DIP switches. And I only care about a few of them,
like the 80 40/80 column mode and things like that. So I’m going to put some toggle switches
back here on the back and run those over there. So, that’s the plan. Let’s get to it!
I’ll need to remove the motherboard, which is just held in by 4 screws.
And now I’ll get to work desoldering.
OK, now time to put some masking tape on here and mark where my various holes are going to go.
Now, I’ve never drilled in acrylic before, so I’m no expert by any means. But I did watch a
few YouTube videos on the topic and they all said I needed a backing board of some kind.
So I’ve cut a piece of scrap wood and I’ll clamp it on here.
Next, I’ll drill my pilot holes. And here’s the weird part. A number of YouTube videos suggested
using a step bit with dish soap on it. I don’t know if this is really necessary but
I guess it can’t hurt anything. So here we go. I was also trying to support it from the piece
of wood as much as possible so that I didn’t break any of the glue joints on this thing.
Anyway, it took a while and I went really slowly. But it seems to have worked.
Let’s pull the tape off. Not bad.
Yeah, I’m totally happy with these. My main goal was not to crack the acrylic, and I didn’t.
Now I’ll test fit the power jack. That’s the larger of the holes. And it seems to
fit just fine. And the power switch will go here. Ok. I’ll just tighten this up and
do the rest. I also made a label on my label maker showing what each of these does. Yeah, I like it!
All right, next I’ll get started soldering in these keyboard wires.
And here they are all done. Again, this will allow me to still connect or disconnect the keyboard,
but it should fit now. I’ve also got all of the wires I need soldered to the bottom of
the board. So I’ll go ahead and put this in and start getting these connected up.
OK, so here’s a little problem I ran into. So, I actually left the original power port on the
board because I didn’t think it really hurt anything being there. But I wanted to have
this other power port on the back. With the little switch, which I wired in to cut the positive line.
But it doesn’t work. And what I actually realized is I wired this all up right,
What I didn’t realize is that the original power supply that came with the mini PET is actually
center negative. And I wired this as center positive. And I really actually despise center
negative connections because half the time people are going to wind up plugging the wrong darned
thing into it, because almost all barrel jack power supplies are going to be center positive.
So, I think what I’m going to do is
rewire the power supply to be center positive and go ahead and just remove this power jack.
And so here we go. I didn’t really want to make any further modifications to the Mini-Pet, but I
don’t want to risk leaving this power port in having it backwards polarity.
And what I’ve done is chopped the wires on the power adapter and reversed them.
Now I’m soldering them back together so it will be center positive.
OK, I think we have all of the important stuff connected. Time to attach the keyboard.
Yeah, I think this is going to work just fine. I’ll go
ahead and screw the keyboard back in place.
OK, so I haven’t installed the top yet, but I’m going to go ahead and power it on.
Fingers crossed. I’ve got audio and video hooked up to the monitor, which is
something the original board didn’t have. I’ve got power and keyboard. Let’s see if it works.
All right. The keyboard is working. Let’s try the 40/80 column switch.
That is also working. Yeah, excellent.
So really the last thing I need to do here is reinstall the top piece
and clean up the mess on my bench, and I’d say this project is done.
And here we are. I think this PET project turned out better than I expected.
I’m totally thrilled with how it looks and how it works. And
taking a look at the bottom you can see all of my wiring there.
OK, so I just wanted to give you a little quick overview of what I’ve added on the back. Obviously
here we’ve got the power switch. Makes sense. Obviously there’s the DC input, center positive
like I like. 40 or 80 columns and then the only reason I put this in is because I wanted to have
that custom Petscii Robots font that I created just for the game, that way I can turn that on
or select the regular Commodore PET font for any other software I want to run on there. Obviously
standard video output and the audio output, which is actually something I really enjoy having on
here because the built in speaker is very quiet, and this helps a lot. Let’s plug this thing in.
So, I want to test the Mini-PET on these 3 different monitors. Each one has their
own pros and cons. And, well let’s just see which one works the best with this computer.
Let’s try the Samsung TV first. No surprises here as we already know it works pretty well
for 40 column mode. In fact, it actually looks slightly better in person than it does on camera
due to the moire effect you see here. OK. So far so good. What about sound? I don’t know
anything better to try than Shiru’s Faulty Robots sound demo for the PET. I’ll crank the volume.
So yeah, this TV does pretty great in 40 column.
But what about 80 column? Well, that’s where things get a little blurry.
I’m not saying it is unreadable. But it’s certainly not comfortable to read. However,
since I modded this TV to support RGB, I’m going to show you a little trick. I’ll plug the
composite into the green input. And now I’ll flick the little switch. And take a look. I think that’s
a small improvement over the composite image. In fact, I can move the cable over to the Blue
input, or or over to the red input. So I get to chose my color. But I think green works the best.
But let’s try another experiment. Here I’ve rigged up some splitters so that all 3 colors
are receiving the same monochrome signal. So let’s see how this looks.
And what do you know.. that’s decently readable. Unfortunately the black level is a bit off on
my RGB mod because I have the wrong value of resistors in there, and I need to go fix that.
But it’s actually exaggerated on camera, the background isn’t quite this gray looking
in person. Anyway, this is very readable now in 80 columns.
OK, next lets try the Tandy monitor. I’ve shown this one before. This is usually my preferred
monitor for monochrome applications. Since it has no shadow mask, and no color signal,
it’s really sharp and clear. And it looks good here in 40 columns. And no surprise,
it looks really good in 80 columns as well. So, this should be the perfect monitor, right? Well,
not exactly. Here’s the one downside. It has no audio so we’re depending on the internal speaker
in the mini-PET, which is unfortunately not very loud. And now that there is this acrylic case
around the board, that blocks the sound even more. So, ideally, we really need a monitor with audio.
So, what about this LCD television? I’m usually not fond of LCD monitors connected to
retro computers. But at least this is an early model that has the correct 4:3 aspect ratio,
and it actually has good speakers on the sides, something most Modern LCDs are lacking.
So yeah, this TV works pretty well for 40 columns. It doesn’t look too bad, and has great sound.
OK, what about 80 columns. You know what.. to my surprise, it looks pretty good! It’s not as
sharp as the Tandy monitor. But makes up for it to some degree due to the lack of visible scan lines.
So, this is totally readable. So, which monitor would you pick to use with this Mini-PET?
OK, I have one more little bonus thing for this episode. This CBM 4040 dual disk drive was
recently donated to me by Yue Fan, who is local here in the Dallas area.
It was unknown if this thing even worked. So I thought I’d connect it up and find out.
Unfortunately, the connector here is not labeled as to which side is up,
and it is also not keyed in any way. So what I’ll need to do is find the ground pin with my
multi-meter. Ok, I think that is it. So I’ll go ahead and put a label on here for the future.
Well, let’s plug it into the mini-PET. Now I’ll power on the drive.
I hear it doing a headband, so I think that’s a good sign the CPU is alive. I don’t have a disk
in the drive, but I’ll try listing the directory just to see if the drive responds, and it does.
So this time I’ll put in a disk that I know has data on it it. And I’ll try the directory again.
And check it out. It actually works! OK. Let’s see if the other drive works.
This is the only way I know to get the directory on drive 1. And
there we go, that one is working too! I honestly wasn’t expecting it to be in working condition.
I do need to clean it up real good, and probably lubricate the drives and such, but
that will have to wait for another time. Anyway, so a big thanks out to Nick for building this
case. There may be some additional info about that in the description field if you are interested.