atkelar | Restoration Project #29 - Commodore VIC-1520 @atkelar | Uploaded September 2021 | Updated October 2024, 13 hours ago.
When I made my Commodore MPS 803 printer restoration video (over here youtube.com/watch?v=0BVbS_mJFNg) one of my friends remarked that "he wasn't as lucky as a kid, because he could only afford the plotter"... To which I replied: "What plotter?" and the rest is history - or rather another project video. What can I say, I have a thing for plotters. And an 8-bit computer plotter? Count me in!
Little did I know what I was in for. These little plotters make use of a generic pen plotter mechanism that was "cheap". It has no end stops, so to "home" in on the head, the plotter drives it to one side until it hits the wall and then some more. This relies on the motor stalling and the gears keeping all toothes together. Brutal, but hey, they could omit one switch from the BOM. It does have a reed relay for the pen color detection though.
The little sprockets on the motors are notorious for cracking, since they are press fit on the motor and shrink over time. This is what kept me from restoring the plotter for so long. There are replacement gears - which I found rather late - but they are either 3D printed (probably less accurate) or made from brass (which would wear down the NEXT gear in the chain eventually... So I was keeping an eye out for options. And eventually, I found one that seems to tick both options: accurate enough and just as soft as or maybe slightly softer than the originals...
0:00 Intro / Unpacking
1:30 Paper Roll Holder Remake
2:50 Case Disassemble
3:38 Recapping
4:23 Sprocket Issue
5:50 Molding / Pouring new Sprocket
7:01 Mechanics Disassemble
8:51 Pen Spring Issue
9:41 Pen Spring Remake
11:30 Mechanics Assembly
13:20 Pull String Assembly / Final Steps
14:38 Backlash Gear Spring Remake / New Sprockets
15:38 First Test Run / Pen Pressure Adjustment
16:30 Testcode & Plot
17:45 Final Presentation / Credits / Outtakes
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
German C64-Wiki about the 1520: c64-wiki.de/wiki/VC-1520
You can support me on Ko-Fi: ko-fi.com/atkelar
When I made my Commodore MPS 803 printer restoration video (over here youtube.com/watch?v=0BVbS_mJFNg) one of my friends remarked that "he wasn't as lucky as a kid, because he could only afford the plotter"... To which I replied: "What plotter?" and the rest is history - or rather another project video. What can I say, I have a thing for plotters. And an 8-bit computer plotter? Count me in!
Little did I know what I was in for. These little plotters make use of a generic pen plotter mechanism that was "cheap". It has no end stops, so to "home" in on the head, the plotter drives it to one side until it hits the wall and then some more. This relies on the motor stalling and the gears keeping all toothes together. Brutal, but hey, they could omit one switch from the BOM. It does have a reed relay for the pen color detection though.
The little sprockets on the motors are notorious for cracking, since they are press fit on the motor and shrink over time. This is what kept me from restoring the plotter for so long. There are replacement gears - which I found rather late - but they are either 3D printed (probably less accurate) or made from brass (which would wear down the NEXT gear in the chain eventually... So I was keeping an eye out for options. And eventually, I found one that seems to tick both options: accurate enough and just as soft as or maybe slightly softer than the originals...
0:00 Intro / Unpacking
1:30 Paper Roll Holder Remake
2:50 Case Disassemble
3:38 Recapping
4:23 Sprocket Issue
5:50 Molding / Pouring new Sprocket
7:01 Mechanics Disassemble
8:51 Pen Spring Issue
9:41 Pen Spring Remake
11:30 Mechanics Assembly
13:20 Pull String Assembly / Final Steps
14:38 Backlash Gear Spring Remake / New Sprockets
15:38 First Test Run / Pen Pressure Adjustment
16:30 Testcode & Plot
17:45 Final Presentation / Credits / Outtakes
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
German C64-Wiki about the 1520: c64-wiki.de/wiki/VC-1520
You can support me on Ko-Fi: ko-fi.com/atkelar
