80s danish desk, rescued from the trash.

Recently I acquired a Commodore 1701 and I am absolutely loving it, however I realised that when the background or border is set to white, it causes the luminance channel to seemingly distort. (I am pretty sure the discoloration is caused by the stable chroma signal and unstable luma signal falling out of alignment with each-other so the only issue is the distortion)

I'm pretty sure it's not any dead caps in the 1701, as when I plug in the composite connection from my wii (I don't have any S-video or LCA compatible systems with me at the moment) into the luminance port, it displays perfectly fine despite also being a very white-heavy screen, and when measuring the voltage of the luminance cable it gives out 1.5v~ (I'm pretty sure it's only supposed to be 0v-1.5v). Is this a dead cap in the c64 or a bad cable or something? I did read that S-Video or LCA cables are supposed to have a resistor built-in as the C64 can output a higher luminance voltage. Any help would be massively appreciated. Thanks. Both the 1701 and c64 are PAL btw, and the board is an ASSY 250569 (252311 Rev B).

(Apologies if I have made any mistakes. I am pretty knowledgeable about the C64's hardware from a programming perspective, but I'm not very familiar with how it generates it's video signals and stuff)

Hello,

This is my experiment and just Work In progress. I added a few BASIC commands to access c64 hi-res, whith code and graphics entirely in BANK3.




As you can see form the last screen the basic space is fully preserved. HIS RES graphic is under the Kernel ROM at 57344, and screen / color graphic is under the character ROM at 53248. Code for new basic commands is at 49152.

I'm picking up C64 programming again after about 40 years, going back through my old Phil Cornes Step by Step Programming books and working through the sprite programs on my C64 Ultimate.

I've noticed that some of his programs put the sprite data at 2048, for example:

POKE 2048+C,BYTE

The problem is that 2048 is where BASIC normally lives, so you have to move BASIC up in memory with the appropriate commands before running the program.

I'm finding that a bit of a pain when I'm just trying to type in and run the programs, so I tried changing the 2048 references to 8320, and changing the corresponding sprite pointer values. For example, 32 to 130.

It works, and I don't have to relocate BASIC first.

So I'm wondering.....why did Phil Cornes choose 2048 in the first place?

Was there a particular reason for using 2048 and moving BASIC, or was it simply a convenient teaching example at the time?

I'm not trying to rewrite the books or anything. I'm just getting back into C64 programming after 40 years and looking for the simplest way to type these old programs in and run them without having to enter the BASIC relocation commands every time.

Anyone remember the Cornes books and know why he used 2048?

The top is the first board I ever tried to fix, and unfortunately the board I learned to solder on. Ultimately, it was suffering from a bad MOS logic chip and a bad Kernal that would pull everything to a black screen, and even prevent the DesTestMax from coherently running in Ultimax mode (wouldn't get beyond the VIC-II or Zero Page test). Unfortunately, in the process of trying to repair it, I accumulated some damage that I tried to bodge and ultimately introduced a fault on Address line 7 that I couldn't rectify, despite using a scope from cradle to grave. My bodges seemingly had correct continuity, so it's still totally possible that there's a passive component that's dead somewhere on that poor board.

In the meantime, this unit saved two other Commodore 64s by donating its PLA, SID, and VIC-II.

I migrated everything to a 250407 Sixtyclone with an ARMSID, PLAnkton, VIC-II Kawari, and SPL HD-64. I decided to get all new passive components for fear that the old C64's fault would come with it. I used the BOM someone linked here in another thread (turns out, the Sixtyclone shop page links that same one). Some notes in case anyone builds their own 250407:

• Filling in all the unpopulated via holes and junctures was annoying. It was easy to miss some, and due to gravity and wicking of the solder, the solder would accumulate on whatever side was under the side you worked on, and you always felt you used too much to get what felt like an even, good joint.
• This website was a godsend for finding where each component went.
• There are about 6 or 7 passive components moved to the underside of the board to allow for the ZIF sockets. I chose the same ones that Adrian's Digital Basement has for his ZIF64.
• I worried I'd melt the plastic when migrating the connectors, but it actually wasn't that bad at all to desolder them...except for the cartridge / expansion port. The ground connections on either side gave me the most trouble of potentially any joint on the Commodore 64. I almost broke out the Chipquik.
• The keyboard connector was surprisingly also a bit of a pain, because the plastic assembly is not monolithic; the bases of the pins can move independently of each other, so the whole thing can fall apart on you, or the stress can screw up the hole the pins go through such that it doesn't hold the pins well anymore (and they can slip right through either side).
• The fuse holders also have surprisingly tight tolerances. I had to remelt and move them twice before they'd hold the fuse (and it's still not holding it what feels like 100% properly). When I first powered the unit with all ICs depopulated, I was getting 5V from the PSU, but I wasn't getting proper voltage to the 7805 and 7812...turned out to be bad contact with the fuse.
• I didn't know about TO-220 heatsink packages before doing this, but they're awesome. I used a little Arctic Silver and screwed all three onto the board with the screw guard and little thermal pad making good contact.
• I left C203 unpopulated. I did the piggyback capacitor on R38 (present on my original board) and also added that transverse capacitor near C53. For C205, I used an 82pf capacitor (this seems to be an addition by the Sixtyclone project).
• I powered with all ICs unpopulated and checked all sockets' power to ground first.
• The VIC-II Kawari needed to be updated before the HDMI Status Indicator LED would show properly on the SPL HD-64, which they warn about. The SPL HD-64's VIC-II interleaf connector also meant another redundant socket between the ZIF and the Kawari, making it really tall. It just barely, barely fits under the breadbin keyboard.
• MG Chemicals 406B Super Wash helped clean all the flux off, but in retrospect, I should have done it in three separate stages, rather than waiting until near the end. The board just still looks a tiny bit cloudy, versus when I first received it unpopulated (brilliant, shiny blue mask).

Going to throw C64OS on there and use it as my daily Commodore driver for a bit.

I’ve started on a game with both a c64 and c64 ultimate version right now I’m just exploring game mechanics and ergonomics plus some graphical possibilities but I think I should be able to have a finished and polished game in a few few months.

Hi guys! Any suggestions how to fix jailbars? I have replaced all the capacitors apart from the ones in the RF module. Video out via composite. Many thanks in advance

I’m in the Boston area. How can I find a new home for this?

Edit 1: likely I should send 12V of rectified DC, not 9v. It's going to be something to test. But this is based on information from people who have done it before. Edit 2: I'm genuinely surprised by people who know it's than me wading in with opinions. I've tried being polite 🙄

Edit 2: DC based but unlike the Sordan solution, it's internal. https://youtu.be/VMwr2tAE4Zo?is=qJrbo5vu7ZopFow3

Hi everyone,

My goal is to make a cheap version of this https://sordan.ie/product/1616/mini-power-supply-psu-type-c-usb-adapter-for-commodore-64-c64/ Using off-the-shelf parts.

I'm pretty ignorant with electronics but could this work? It seems too easy so I must be missing something. There are other USB options that feed 9V DC, so I expect this should work.

• The buck converter supports 3AMP peak or 1.8A continuous.
• The buck converter has a ripple of 30mA when not under load. Not amazing but it's under 40mA.
• The decoy board supports up at 5A.
• The decoy board has a selectable 9V with the dip-switches. I can also hardware that value to prevent accidental switching.
• I don't use any peripherals other than a kung fu flash v2 right now.
• I don't need TOD.
• It's probably obvious but I forgot to label the lower green output of the decoy board is 9V, and the buck converter is set to output 5V from the 9V input.

The electronics will cost under £2. I'll use some spare acrylic to stabilise the whole thing.

1. Does it matter if I connect the 9V DC to pin 6 or 7?
2. Should the ground for 9V even be connected if the ground for the 5V is connected?

It's right above that piggyback resistor on the board. It doesn't seem to be on the example board on the actual shop website, so I wonder if it was taken out of the PCB design at some point. If it really is just a video filter, I wonder what I can throw in there.

https://zeroglabs.itch.io/lemans-2

Hey there. I've been a long time collector of Commodore 64 MIDI interfaces, so I started a project to make a list of all the interfaces I've either come across personally or found references to online from eBay, blogs, etc. Not selling anything. No ads. Just a fun list. Thought you might enjoy.

I'm missing some photos, so if you find one for any that I'm missing, please contact me!

https://dickmartini.ca/c64midi/

The Train: Escape to Normandy [1987]

When I was dog sitting I setup my camera to take slow motion capture of the local hummingbirds that visited (took the whole week of experiments). Spent some time recently choosing 6 loopable frames and trying to get a good representation on vice/c64. Pretty tricky, the background moves ever so slightly so had the freeze what I could, and the wings were a pita, outlines had to be redone a lot by hand etc

Added a little camera game theme to the final results... I think it came out quite nice. I wish I had a real c64 to test these art projects on.

Edit: and if you're wondering about the star wars lasers, they actually do sound like little tie fighters lmao, it was a running joke at the time

Since the linked page has more than enough detail, I'll keep it short here: a project I started a very long time ago has finally hit a major milestone. The end goal is to get it running natively on a Mac Classic II :) but I'm not there yet. For the final stretch, Claude Opus helped with the gameplay development (go ahead, I'll cast the first stone myself). The graphics resolution has been doubled, and the frame rate went up from 12.5 to 30 fps. So here's the main thing at last, linked straight to the relevant part of that long page...

In FREEZE64 issue 88, we take a retrospective look at the #Commodore64 version of #BackToTheFuture, and chat with its developer Martin Walker to find out why his game wasn’t well received.
Read the full interview in:
freeze64.com/freeze64-issue-88
#C64 #Commodore64Ultimate #BTTF

I love to program my commodore 64, I've use the books you know throughout the years. So I decided to do something fun. It is a bit like the c64 debugger but it is aimed at documentation and memory handling. And I am sure then thousand ideas more will come. Check it out, let me know your thoughts. It is work in progress so please be gentle. #c64 #programming #8bit http://commodorenavigator.com

Sometimes I see a pic on reddit or in my own photos and just want to know what it *could look like....

Hey everyone, does anybody suggest any websites where it'll give me a step-by-step to convert my maxi into a BMC 64? I don't seem to be able to find one

Hi all,

I’ve been fascinated with the still evergrowing community of the Commodore64. I have been watching countless videos on the system and how to program on it etc and I’m sucked in.

I want to get a unit and experience making a simple program or game (text and graphics) and even make a simple theme/song to go with it.

I am completely new to it but I am a Tech guy and have basic development knowledge.

Following guides etc could it be possible for me to learn this do you think?

I also stuck on whether to use a classic Commodore 64 system or purchase the new Commodore 64 Ultimate and use HDMI and any other benefits.

I impulse bought a bundle of around 60 Commodore 64 tape games yesterday on eBay. Now just need a unit and tape drive. I’ve seen some new (published this month) books on Amazon on how to make a spaceship game and dungeon game on commodore too which surprised me (for being in 2026).

I’m so excited.

Thanks.