Remember a couple weeks ago, when I showed you a different VW Beetle drawn on an old, obsolete computer, I also told you about an even older, obsoleter computer that was sent to me by another Autopian reader? Of course you do. That’s not the sort of thing you forget. Well, that other computer, a Commodore PET, was broken, with a capacitor that spewed magic electric smoke. Well, as you can see, it now works!
The fix was, happily, pretty simple, thanks to the fact that I could actually see the failed component leaking smoke. So, I found out what sort of capacitor it was (10uf, 25V, tantalum) and ordered some new ones. I got the old one out of there, and then carefully yet clumsily soldered the new one in. I’m out of practice at soldering and, let’s be honest, was never great at it, but happily, with the help of a magnifying glass and something that’s at least tangentially related to patience, I got the new capacitor in place:
All the goop that was in the old capacitor when it burst however many years ago is still there on the board, too. After I got it in place, I used a sophisticated electronics repair technique called “hoping” to be sure that was all that was causing the machine to not turn on. I hit the switch and after a few tense seconds of nothingness, I saw the text on the screen announcing the system was alive!
I messed around with it a bit, and realized that to truly inaugurate yet another old hulking boat anchor of outdated electronics into my life, I need to draw a VW Beetle on it. That’s just what I do, you see:
For the PET, the trick is that the machine has no real graphics modes. It can only do text. But, Commodore engineers and designers knew that wouldn’t satisfy all those creatives in the world, so they added a bunch of graphics characters to their character set, known as PETSCII:
So, these are the tools I had with which to build my Beetle. I ended up with this:
I like how the program listing shows the image just as clear as when it’s actually run. I assigned each line of the Beetle to a string variable, and then, those of you in Club BASIC may be noticing, I’m doing a bit more with it all by the end. I figured I should at least try a simple goofball animation with the Beetle, because it’s a CRT, not a printing press, right? So that gave me this:
That’s by far the easiest, smoothest way to animate this, up and vertically, because that’s how the hardware scrolls text. Any other way would be a lot choppier, I think.
Anyway, I’m calling it a victory. I’ll take them when I can get them.
UPDATE: Our TotalSally partnership for rapid-turnaround shirts pays off again! Want a PETSCII Beetle shirt? You got it!
I have a sudden urge to start collecting old computers…
First cats, now retrocomputing, I like how you’ve expanded things. Cars are important, but not the only thing.
Great work! The video version needs the sound of Atari’s E.T. falling down a pit (looped a few times).
The 8-bit guy on YouTube is pretty interesting for old computer history and repair
Haven’t fired up my PET for 30 years, so it probably needs caps, too. But I’m more interested in the Apple next to it. Does that still function? Far more capable machine (and you paid for the difference).
My PET cost my $712 in 1978 (9?) and it launched me on a very lucrative engineering career, because Sperry Microwave Systems was looking for a computer programmer. I spent a few weeks on the PET and learned enough on top of my IBM punchcard experience to BS my way into a real job. Thanks, Mssrs. Jack Tramiel and Chuck Peddle, you changed my life!
If it makes you feel any better your soldering still looks miles better than when I replaced a micro USB port a while back. It was a complete shit show, but in the end it worked and I still use that device, which I couldn’t have done otherwise.
In my defense, I solder about once every two years and in between I forget everything I know about it. 🙂
Woohoo! Glad to see the
ChiaCommodore PET up and running. Does this mean that we will soon be able to post PETSCII images in the comments?Programming old computers to do things like this is totally pointless, but I used the exact same amount of time to do absolutely nothing of value, so I’m the one actually ashamed of my productivity today.
That bottom line of PETSCII spells out “kill John Connor.”
But only the machines can read it.
Little known fact: John Conor’s adoptive mom in T2 who impales her husband through the head in the kitchen was played by the same actress who played the badass marine Vazquez in Aliens.
Just wanted to pop in here and say I received my sushi taillight shirt! Looks great!
speaking of shirts: https://www.totalsally.com/product-page/ready-unisex-jersey-short-sleeve-tee
Jesus Christ there are some smart folks round here. I feel lucky if I can turn my frickin’ MacBook on without screwing something up. And once Parkinson’s set in, well shit that’s the end of screwing round with solder and hot pointy things. And found out that using a torch to solder shit just melts the boards…Cool burning smells though.
Now quit playing with your toys and write more content please!
In line 200 couldn’t that be ‘GOTO 100’ instead of 10 or does it really forget the values assigned to those variables with each loop?
oh! you’re right–it could! That’s speed it up!
Glad I could help 😉
I would expect nothing less from a person with Binary for a username.
For future reference, the correct programmer’s response is “Of course, but I did it the other way because it’s an effective method of slowing the display.”
Here I was thinking a chainsaw would come into play.
Technically it did. Jason used the lead collecting in his blood from the chainsaw incident to do the soldering.
Torch, you need to make the animation go from the top down, not bottom up.
That way it looks like the car is coming toward you, not backing away.
Typical product manager changing the spec after the code is done
I am appropriating ‘something at least tangentially related to patience’, and am eagerly awaiting a chance to use it irl.
Would it kill you to add the spaces to centre the image in the screen?
It seems Jason instead chose to stay in his lane.
Just remember, if it asks you “shall we play a game?”, pick chess
I think you need a modem to play THAT game.
And tell it your name is Joshua
The only winning move is not to play!
That’s not a bad way to start a Monday morning. 🙂 And I appreciate your willingness to repair rather than scrap or replace. Excellent job!
My soldering skills are sus and largely limited to wiring harness connections. The cap – actually the whole board – appears to be through-hole, which IMO is much less fraught than SMT.
Does Commodore BASIC have a function to renumber the lines? IIRC TRS-80s used ‘renum’ and you could pass two arguments to it: the line number on which to start and the interval. So if you wanted to renumber the lines starting at 100 and going up by 10s, you would enter ‘renum 100,10’.
As I often say, “If it’s ugly and it works, it’s not ugly”. 🙂
Dang, good idea LOL
This may work to make it look bumping up and down
Add
5 CLS to the beginning
then a another line with just a space. Then a goto line to the top
Then a goto the the space line
It’s been 40years since my basic days…I used to play on a TRS-80 back in the day.
Your TRS-80 roots are showing. CLS doesn’t work on a PET. The equivalent command for clearing the screen is PRINT”that special reversed heart-shaped PETSCII character produced by pressing the SHIFT and CLR/HOME keys” which is to say, effectively, PRINT”CLR” except using a reserved character to represent CLR.
Funny, microsoft has carried cls thru all their OSs. Never knew Basic was different on OSs. I went from the TRS-80 to an IBM based PC and tried learning 8080. I gave up LOL
The various versions of Commodore BASIC are basically Microsoft BASIC but with just enough differences to make things awkward. I learned Commodore BASIC 4.0 in high school only to be stopped short when my school switched to the Apple //e which, of course, didn’t have, among other things, PETSCII-based commands.
Having grown up squarely in the era of CRT TVs, I see that animation and I want to pound on the top of the unit to make it stop.
Just relax … it’s just your VHS vcr tracking is off.
As a former Commodore owner, car guy, and computer nerd, I support these efforts.
As an old computer guy and old car guy, I heartily endorse this content. But how about a trigger warning when displaying your soldering efforts?
I mentioned I was garbage at it!
Fair enough. Full credit for the “Just Send It” attitude with soldering and chain saws.
It’s a great soldering job, it works.