How-To: C64 Arduino based Restore Key/Four Kernal Switcher/Hard Reset 

Nice mod, although the fact that you are using a more powerful processor to control ROM selection makes me smile...

I like the stacking sockets trick, works out a lot neater than bending pins up and soldering to them, as I've seen on other mods.

Hi Adrian! Just found your channel. I'm a old C=64 demo coder. Not been active for many years. It seems like there is many new awesome HW mods for these lovely old machines. Keep up the good work! =) Subbed and belled.

since you are driving the LED from the Arduino, why not use an RGB LED? then you can further indicate which Kernal is in use via color effects.

Really cool! Great video as always Adrian

Excellent tutorial! I've wanted to do this myself for a while and I'm excited to see it all laid out like this. Great tips about the sockets will save me some time. Thank you!

I'm addicted to these Commodore videos. More...MORE! Thank you!

Great video! Really like the way you approach showing what you're doing and walking through why and how.

Just wanted to thank you for all of the videos. Your videos have sparked a lot of ideas and fun things to work on. The arduino concept was great. I'm working on an ATTINY85 version for myself.

Wow!!! Fantastic! Simply fantastic!!! I don't know how you came up with this but fantastic! Thank you so much for sharing!

I am all in for the Commodore basement, way more interesting than videos about beige box PCs. Keep it Commodore, Apple and Tandy. You always do great videos and I totally enjoy watching them.

Adrian, love your channel!!! You re-piqued my Arduino interest. Now I have to find a project to use one.

Loved this video. Clear and well-paced. Thank you!

I agree with not liking to drill into perfectly good computer chassis. When I mount SSD's in laptops, PC's..whatever...I turn into an artist as I mount these, using existing holes in the case. @7.20...that's a NICE reveal when you open up the top, great great job.

Loved the blooper at the end. Mama We're All Crazy Now is a pretty good song!

Excellent video Adrian. I’m looking forward to trying something like this later this year.

This is an awesome instruction. Subscribing right away! Really, one of the cheapest and at the same time most convenient ROM mod.

Great topic, helpful video thoughtfully laid out and edited. A true service to the community. Thank you!

Really, really enjoyed this. Something I'm seriously considering doing myself. I like a project I can see myself doing. As much as I love repair videos unless I have that specific problem I can't follow along at home.

Fantastic choice of game to test @2:50 👌 I'm switching my pastime from coding to electronics so it made my day to happen across this.

Great video! Thanks for all the work you put into this!

Great vid, as always! And outstanding design work!!

Amazing video. I thoroughly enjoyed it. I would never have the patience and skill to do what you do. Thanks Adrian

"Adrian's Commodore Basement" - Subscribed!

This project is AWESOME! Lately, I've been sad knowing I gave up all my commodore hardware many years ago. Used ones are like through the roof, been thinking of just buy parts and making a project out of it piecemeal style. I would definitely attempt this mod if I had a C64. Your channel here among the many others like it are fantastic.

Man you make this look so easy! Not sure if I'm game... Good video!

Great video! I've never used a C64 before (I'm a Trash-80 man myself :) but I love your tutorial. It brings together the technique and art of us old time Hackers (good use of the term) used to 'create' the PC in the first place. Keep up the great work. Thanks.

Great work on the kernal switcher and the adapter. I made a similar thing and board and videos a while ago and i gave up on the dual socket adapter. I just couldnt get my head around it so I made a pcb instead with a 8 pin PIC12F micro inside the eeprom footprint.

I have almost no clue about what you said... but I still enjoyed it! My first computer was a Kaypro 2X, so I can't wait to see that episode.

Great work. Love your enthusiasm and skills. 😀

Pretty stoked on the successs of your channel. I subbed back when you realeased the review of the dollar store LED light bulb because it was recommended from Big Clive's. Hit that RU-vid algorithim jackpot haha.

I'm fairly new to your channel, but what a fantastic project video this was. Great job!

Enjoyed this, Learned a lot Adrien, Awesome!

Love this!! Wish I still had my old C64 just to try this!!

Now, I have made an adaptor board that fits into the short board as well. It holds the Basic and up to 7 Kernals in the 27C512. The pin header on the board would connect to your pro mini or other micro controller module. It requires a 7408 AND gate chip to separate between BASIC and Kernal access. I really like your project here. I hope, it will fit into a C64C case...

You can never have too many Commodore videos!

That's a very nice and useful mod! Thanks for sharing.

That shirt is AMAZING!

C64 hardware mods ...great stuff!

Very interesting! I'm working on a similar project for my Apple IIe but I may have to change things up after seeing this.

So cool - a super-advanced modern Arduino which allows fun and games from the past.

That red wire you were using is wire-wrap wire. Probably Kynar insulation. Really handy for PC board modifications. The only thing I'd do a little differently is strip the wire back about 1mm (3/8") and make a loop in the end that wraps all the way around the pin ferrel. It will stay in place better when you are soldering, and will be less likely to pop off in the middle of the night sometime.

hey love the commodore stuff man

Nicely done! It's a carefully-considered design, and the explanation is very clear. When I get around to putting my C64 back into service, I will likely give this a go. For folks without an EPROM programmer, there are services that will program and ship one to you. The price is usually very reasonable when you only need one chip. I've used HobbyROMs and HighScoreSaves with good results for unusual PROMs/PALs my programmer doesn't support. Putting a sticker or tape over the EPROM window is cheap insurance against future problems. More than once I've had to re-burn an EPROM on an arcade PCB that sat on the shelf uncovered for many years. I don't know exactly what conditions caused it to lose data, but this was enough to convince me it's worth the minor effort. Custom-printed stickers make a nice visual enhancement, too. Best of luck with your future, repairs and projects!

You can also do a reset button using an SPST switch and soldering the pins via wire to the port (left from front of case) pins 1 & 3 (from rear of case pin 1 is on the right) One is a ground and the other is a negate reset. I remember doing that to all of my C64's when I was a kid. Thanks for all the great memories Adrian.

Well done, Adrian. It is so much fun to connect a much stronger processor than the 6510 just as a Kernal-switch :-) BTW, you speak a very nice English, so it is easy to understand.

For extra future-proofing of the C64, get one of those CPLD based replacement PLA chips, which run cooler and last way longer than the original failure-prone chips. I've got the PLAnkton in a couple of my machines and they work great.

Awesome thank you. I’m going to try this myself 😊

Hi Adrian, I just subsribed to your channel. I'm a long time C64 user, but just use emulators now. I am jeolous of your physical computers and what you are doing with them. I am a developer and in my spare time I write and sell my own software to opperate model trains. Really cool mod! Nice job! You've hot me hooked on your channel.

this is a great project. im totally going to make this but use an AT28C256 EEPROM so i can easily change up the Roms. many thanks

Great guide. I would maybe make key combination to select roms, lets say Restore+ Function keys, but this way is great as well.

I do have one recommendation; before you “install” anything in the C64, desolder the old 24-pin socket and replace it with a 24-pin machined-pin socket; if you insert the round pins from the “adapter” into that old socket, the springy fingers in the socket will be deformed by shoving in the round pins, and they’ll make intermittent contact over the years. By replacing it with the higher-quality machined-pin socket, you’re now putting round pins in round holes! 😊 Another option is just to solder the adapter in directly, though you might have to move a decoupling capacitor or two to the solder-side of the PCB, or they might interfere with the 28-pin socket’s “footprint”. Never mind, you fixed it! 🙃

I'm not sure why this 2 year old video popped up on my stream last night, but I enjoyed watching it and may have a go on my own C4. As for those single wipe sockets, I hate them too!!

Excellent video, thank you!

Nice and clear. Don't own a C64 however find the subject very interesting. Maybe you have to design a PCB for it or a kit that people can buy with preprogrammed EPROM and Arduino. Still put a sticker with version info on the window. Nice video and your solder job is also excellent. Great video.

I love this a LOT!

Very nice.. wish this was available 30 years ago! Although I also like the industrial look on my C64 with al the push buttons, switches & LEDs ;)

very interesting. I did not you could do that. making me think things. Thank you very much for sharing.

I love watching and understanding retro computer refurbishing/modding videos, the only thing I don't understand is what people do with them after they're done. I have 2 C64's in the garage somewhere, but after I managed to get them working and played a few games, they were just collecting dust, thus ending up in storage.

That's an awesome project, very elegant. My only feedback is that you may want to make those LED blinks a little slower, so they are easier to see. Now I want to get a Commodore just to do this with it :D

I modified my C64C following these instructions. I had a bit of a problem getting the solder to take on the socket adapter even with flux but i got there. I used a turbo tape rom in the 4th rom slot.

Just fixed a C64 and working on the HDMI mod (Rf modulator replacement combined with the rgb mod of copperdragon). I'm also starting today with building me one of these :)

Adrian, thanks for this great video. I have a bunch of Commodore machines and drives in the closet, maybe its time to pull them out and see what happens. Back in 1979 (thereabouts) my first computer was a Timex Sincair. It had 15k of memory. An extra 15k cost $300. About 1984 I bought am Apple IIE copmuter. Later on I joined the Marines and Bought Commodore computers at the Military PX stores where ever I traveled. I still have all those computers.

Nice case colour trick! I wonder why I never saw this until now... thirty-five years.

Your soldering is literally some of the best I've seen on channels like these. Have you done rework in the past or have you always been a hobbyist?

Great video. I like Quiet Riot, too.

That's really cool, do you plan on making a video of how you make the multi ROM Eprom?

Actually there was a guy on YT who performed an experiment - wrote data to EPROM and left it on the table, periodically checking data integrity. With time sunlight caused data to deteriorate. It won't erase it like a UV lamp but it will eventually corrupt the information.

I've used a magnetic reed switch before - hot glued a metal plate next to it to hold the magnet when not in use

Really nice mod! :)

And by the way - Sun really DOES erase EPROMs, quite easy actually. Half hour of sunlight is enough to corrupt data, few hours are enough to completely blank the EPROM.

Lots of Commodore stuff... I am not complaining! :)

The round hole ones are called "machined sockets"

Before all, greetings and keep up the good work. I was looking some of your videos and I like it, they're strait and clean explaining tutorials as well as the problem solving and I like it a lot, so you have a SUB and BELL from me :D I'm a fun regarding the old school computers and in my time (the 90's and 00's ) I was a hard coder programmer especially for C64-128-256 series. My obsession in that time was only to figure out some things how to make it easier to use by troubleshooting the user problems, also, my tools that I was using was the binary, hex and machine languages. Right now I'm a little "Forgotten" those but not all of it :D For this video, I've a little suggestion about to make if you agree :D Instead of holding down the restore key to select which OS you wanna use, you can implement a new code to arduino to trace a key combination instead, and take for example restore key + one of the number keys. You just need to take few more readings from C64 keyboard bus routed to arduino and change the code a little bit to enable it to recognize the signals from the keyboard bus. It's a little bit complicated than this version but it's a time saver regarding to resetting the computer and choosing the OS you desire to use on C64 in the future. Also you can use some RGB logic for the LED just to make it little bit interesting about how the led will light regarding which OS is loaded/used.

Thanks for the video! :-)

Creamy Dreamy? What a great name.

Kylar is one type of small "Bodge wire" wire. More commonly known as "Wire wrap" wire. For stripping it I use an Ideal T7 stripper. The T7 will strip down to 32 AWG. Oh, and those are "Machine pin" sockets.

I think this in an awesome idea! you can also use an RGB led to change the color according the system you're loading ;) If i will find another c64 from some flea market I'll do your project! Greetings from italy!

I plan on building it

A better option instead of an EPROM is to use a flash chip. No issues with the wrong wavelengths sneaking in through windows, it's faster to program and much faster to erase than an EPROM, and they're cheap and plentiful. I have a big pile of W27C512 chips that I bought once and have been using one by one to restore old computers with.

Really Cool.

I plan on modding my 64C now. Will let you know how it goes :)

Adrian I have only one comment, Buy your self a set of helping hands there cheap and you won't be struggling to hold things down while soldering. I've had mine for over 30 years one of the best $5.00 I ever spent. Great video

very good video

Awesome video :-) Thnx

My friend put a momentary mouse switch behind the power led on his C64 for reset. Pressing the led has a nice click feel to it.

Note: use 5V Arduino (not 3.3V)

Great idea Adrian. I'm just pulling parts together to take this up a notch and do the same thing to the shortboard versions of the C64 where the KERNAL and BASIC ROM are combined into a single ROM. I'm going to use a 512Kb EEPROM rather than the EPROM you selected and select 16K chunks rather than 8K chunks using A15 and A14. I'm thinking of getting some boards made up to allow the EEPROM to be plugged into a daughterboard that then plugs into the C64 and perhaps a header to attach the Arduino Pro Mini directly to it. As mentioned in your video, the C64C doesn't have as much space as the C64 Breadbin, so I'll need to see whether this will actually work without hitting the keyboard or circuit board. I'm also thinking I may not modify the power LED. My idea is to add a blue LED under the cooling grill that I hope will be easily seen from the user perspective.

This is totally a personal preference thing. The only thing I'd change is the resistor value. I'd go with a 470 ohm instead. I'm pretty sure you know why so I'll leave it at that.

I envy your talent :)

I REALLY LOVE C64 👍🥂🎩

Random Fact: turned pins also make suitable truster outlets on scale models.

I did a quadKernal switchless mod on my C64 few months ago but I did use the circuit from a kind free project made by Bwack on RU-vid :-). Works pretty damn good with a multi color led :-)

the 'shorter leg' on the led thing only works with brand new leds that still have the uncut entire pin. obviously it's much more clear to just look into the led and see which side is the largest there.

This is pretty heckin’ rad. Although this also seems like the perfect kind of project for s specially built adapter pcb instead of trying to Frankenstein two sockets together. Idk how expensive that would be tho

Wow! This would of been amazing in the 80s!!!

It’s fine to route A12 from the C64 to A11 on the EPROM. You just burn the EPROM with blocks swapped around. Specifically, every consecutive quad of 2kb blocks needs to be interlaced. Blocks A B C D become A C B D. That way you’d have one less leg to cut :) But that’s still silly :) One of the larger Atmel MCUs (with 128k of flash) could be used to directly emulate 7 ROMs, or perhaps one with 64k flash could do it if there was a bit of free space in the ROMs - enough to cover the boot loader and the tiny emulation routine (in assembly). That way you could also update the ROMs using the Arduino boot loader over USB :) Or get a WIFI module added and you could update it wirelessly :)

Interesting project, a great way to improve functionality of these machines whilst keeping the original aesthetics.

Love your uploads. Could you show how to put multiple kernals on a single chip one day? I am good with the soldering and programing side. I just don't quite get how to arrange the data on the eeprom and how selecting them works. And because of that I'm not sure what to google, I end up down rabbit holes lol. Not only that but I have an A500 as well now, so there will be a bit more rom madness to do on that too :D

I imagine using vero/strip board and just cutting the relevant tracks would make things cleaner than using two sockets mounted to each other. You could potentially also use an ATTiny instead of a full Arduino.