Fyi, Rockwell chips were developed and used for the Defense/Defence industry so they are always of the highest quality. I used to work for them! :o) Tony K.
Found a VC20 in an E-waste container (jail me, it's illegal in my country...)about a month ago. Luckily only the Kernal ROM was bad. A year ago I pulled an AIM-65 from that container. Throwing one of these away is IMO more criminal than rescuing them.
Wow that was my first ever computer :) my farther bought it brand new back in the early eighties :) I had Omega race, Tornado, Sargon II Chess and Jupiter Lander.
Excellent vid! Have just ordered the same ram expansion you have there, I can't believe how reasonably priced :-) $68AUD around 35 quid inc postage :-) huge cheers from me on the suggestion, and thanks for the vid!
Thanks =D No worries! These days you can also get the "Penultimate Cartridge" from thefuturewas8bit. That provides a load of cart functionality, plus even more RAM.
Yeah, I saw Dave (The8BitGuy) did a good review on them, man my other half is going to start throttling my neck with the stuff I'm doing on the retro machines, I've just done a SCSI2SD on the GVP 500-HD+ I had laying around, recapping old C64's, although I've gotten the kids involved, my 12 year old daughter now gets the soldering iron out having a go, just wish we could get paid to do this daily instead of working :-)
Jesus man, that C64 looks brand new, like me you clearly treat your stuff with respect and kid gloves, I recently had nearly every CD game I own lightly polished and they all look amazing now. Keep up the cool and interesting vid's.
+9ElevenGamer Hehe, thanks =) Yes, it's in excellent condition this VIC-20 at the moment. When the replacement VIC arrives (from AliExpress) I will swap things around and put the good case and keyboard on the original version VIC. It's worth cleaning up your stuff and keep things in tip top condition.
MOS before Tremiel bought them out. Licensed the 6502 and their sister chips to other companies like Lockheed/ Rockwell International, Synertek, Western Digital Design, and even Hitachi and many others. They were 99% compatible across the board with few minor differences.
I've just pulled my old Vic20 out of storage. I did have an issue with it displaying anything, before it went into storage decades ago. I managed to get around it by passing the RF modulated signal through an aerial amplifier. Unfortunately, that dodge no longer seems to work. I did just buy a composite cable for it from eBay, to see if that would give me an output. No luck. :(
It could be a dead VIC chip - that's the most common failure in these. If you have a tape deck or disk drive, you could try loading something (blindly) to see if the tape starts moving when you press return after the load command. Or similarly, see if the SD2IEC or disk drive lights indicate activity after an attempt to blind load.
It can activate the Datasette. My parents weren't rich enough to afford the disk drive. :( I've just ordered a motherboard of the same revision that is claimed to be working. I'll test that it is first. If so, I'll try swapping chips to get the original motherboard working. Failing that I'll put the replacement board in and use the other for spare parts. Assuming all goes well, I'll be putting heatsinks on the chips that are most prone to failure.
GadgetUK164 - Retro Gaming Repairs & Mods It turns out it was the VIC chip. I'm using my original motherboard with the chip off the board I bought. The 'new' board has a dodgy power switch, despite claiming to be 100% functional! You don't happen to know if compatible switches can still be bought new? If I can replace that I'll buy another VIC chip for it.
Another excellent video Gadget, I was about to attempt something sort of similar by modding a 1541 drive to use these newer Rockwell / WDC parts and removing the giant voltage regulators and transformer and replacing them with modern switching equivalents in an attempt to create the most bulletproof 1541 possible by reducing its internal heat production. I never even thought of the difference in the open drain IRQ you pointed out in the video so that'll certainly be something to watch out for in my attempt. Maybe the real test for these 6522 chips is how well they will function in a 1541 thats been parallel modded, but its nice to know with a tiny mod they are almost nearly drop ins for a Vic 20. Cheers!
+aphexteknol You should be fine if you go for the W65C22N. The N suffix parts are NMOS compatible, and don't have the IRQ pin differences. I've used lots of those with no problems, also lots of Rockwell R6522P, so I don't know what the problem was.
+Dave Curran Good to know. As I understand it however, most various 65C02 CPUs however aren't fully (undocumented) opcode compatible with the original NMOS part however. Certain fastloaders are rumored to utilize them so its an issue for 1541s if you want 100% compatibility. Supposedly some or all Rockwell R65C02P chips are, but I haven't dug into the issue deep enough to start ordering parts just yet. The bulletproof 1541 is an idea I've had kicking around for ages, maybe I'll start getting serious about it just to see what works and what doesnt.....
+aphexteknol I have found the R6502P works better than the R65C02P in some cases, but I use both. I don't use the W65C02S as that is a bit too different. I did plan to update my 6502 ROM/RAM board to use the 65C02S in a surface mount part, with the various mods included, but haven't bothered as yet as there still seem to be good supplies of R6502P.
+Dave Curran Thanks again for the helpful information. Also, thank you for the work you put into your blog. It's excellent reading material for Commodore junkies such as myself. Take care.
the vic was my first computer at age 12. i couldnt afford a c-64 at the time..they were still like 600$ then. so i had to wait a year or 2. but that gave me time to learn to program....my dam parents never told me you could BUY GAMES...so i had to write my own..it was literaly like 2 -3 years before i got a store bought game,
and it wasnt untill i was 14 ..and got a c-64 and two 1541 drives...and a copy of 1541 backup. that the piracy really began. got i loved my action replay cartridge. taught me how to crack games..lol.
I have used the Rockwell R6522AP VIA's in a VIC-20 without having to do any modifications. In the video, it shows that Dig Dug wouldn't load, but mine works fine. I'm not loading it from a Penultimate, but from a Final Expansion 3 cartridge. Is there a more comprehensive test to find any possible incompatibility? Also, my VIC-20 diagnostic harness and tests run flawlessly.
It depends how it is loading - if loading from Cartridge it will be OK! The issue arrises when using a disk drive. It may also depend on which 6522 it really is - some of the Rockwell ones are WD etc and vice versa - they relabel them!
Hello Choplifter, it's been a while. :) Dig Dug does look pretty good, the Defender seems a bit less smooth than it should be, though I'm sure it surpasses the VCS version.
Very interesting regarding the difference in the hardware layer of the IRQ pin. Out of interest I looked at the schematics and I couldn't find any other device driving the NMI (Interrupt line for the second 6522), so it puzzles me why the new WDC ic won't work with actively driving the NMI line high, because it looks like it is the only one driving that line... Anyway, very nice mod though. BTw do you have a inline power meter ? You should see a significant power saving from using that cmos device I read :)
+bwack I've read that the NMI line can take too long to transition - don't know how accurate that information is? Seemingly (I really should check with logic probe and scope) when the IRQ pin is low, the diode switches due to forward bias from the pull up on the NMI pin on the CPU, then when the IRQ goes high, the diode is reverse biased, which presumably means it goes high impedence and which point the NMI goes low? I would have through the pull up makes it high still - I am still a bit puzzled as to how this is working... I really should test it later to see exactly how its working.
+GadgetUK164 yes. When the diode is reverse biased (IRQ high) the pull up ensures that NMI go high. I guess you can say that the diode converts the outputstage into wired-OR and eliminates the pull-up network in the ic that the original ic doesn't have. It was the same situation in the 1541C drive. A socket could take a 7406 as is, but also there is a footprint for a diode in case 7404 is used.
+bwack I think it's more important at higher clock speeds. I am using 1N4148 and it's working fine, I do have some BAT85's I could swap it out for if required.
Odd. I am looking at the data sheet of the MOS 6522 and Rockwell 6522* and the IRQ pin should behave identically. Your discussion is short on details. Do you think your Rockwell is a relabeled W65C22S? That's the VIA with the "different" IRQ. The W65C22N is the correct match for the MOS 6522. This is direct from WDC "...some customers have had to use a diode in series with the IRQB output when using the W65C22S in their systems that had Wire-ORd interrupts." Your Rockwell 6522 behaves like a WDC W65C22S. Good to know there are non-spec Rockwell 6522's out there. I have a tube of Rockwell 6522P VIAs. I hope I don't have to mod every one of them.
@@GadgetUK164 Agreed. I have 5 Rockwell 6522P's I recently purchased NOS here in the US. I am hopeful I didn't get relabeled chips. They all say 9110 (10th week of 91?). But they all appear to never have been installed. Cheers!
Great vids as always! I picked up a vic20 bundle at a bootfair a while ago. Weird thing is that the keyboard only responds on a few keys but after power cycle different keys work....? I've had a poke about inside, it looks very clean. Have you heard of similar problems? maybe a chip issue? I may try reflowing solder points.
+The Great Jonzini try swapping the two 6522's around, the one that does the keyboard (nearest the connector) may be faulty. Or it could be a RAM fault, those early large board ones are stuffed full of 2114s.
+bwack That's a good point - reminds me very much of your recommendation on one of my C64 videos when I had random input issues, which ended up caused by the 5v level being as low as 4.6v. Incidentally, if using a C64 PSU like I am here, you will see around 4.6v with clean power socket and switch... The VIC draws a lot more current and the voltage does drop as a result. I must get a beafier PSU at some point soon.
I've done a mod to both of my VIC-20's (both the original model and cost reduced version - same mod to both). I think it was this video:- ruclips.net/video/h79nJFhbOIQ/видео.html
I've recently purchased 2 vic 20's and commodore 64 in the boxes. All in excellent condition. One vic 20 is disassembled with some of the old chips removed and looks like some new chips are on a foam pad in the box but the guy apparently never got around to putting them in. I'm not sure what I'm doing I've never installed a chip like these before any thing I should know about putting them in or taking them out that might make it easier or prevent me from damaging the chips? Also, one of the vic 20's is made in west germany and has gray colored keys which I've not seen before on a vic 20. I have an early vic 20 too that has a square power supply port so I'm curious about what power supply it uses. Great video and I subscribed.
+Nesmaniac Thanks! I am just about to upload another video on the one with the 2 pin power socket - I've modified mine to accept a 12v DC input (which can easily be reverted, so it's not damaging the VIC-20). With regards to chips - it's important that the correct chip is placed in the correct socket, not all chips have their power inputs on the same connections etc. So do make sure you are putting the correct chip into a socket before you power it up, and also check any other chips already in sockets to make sure they aren't the wrong way around or in the wrong spots. There's a semi circle marking on one end of the chip top, that indicates pin 1. The board will have a white outline of the chip drawn in the silk screen (usually covered mostly by the socket), but you can hopefully see from the socket or the white silk screen marking where that semi circle is marked, so you can line the chip up the correct way around.
Fyi, Rockwell chips were developed and used for the Defense/Defence industry so they are always of the highest quality. I used to work for them! :o) Tony K.
Found a VC20 in an E-waste container (jail me, it's illegal in my country...)about a month ago. Luckily only the Kernal ROM was bad. A year ago I pulled an AIM-65 from that container. Throwing one of these away is IMO more criminal than rescuing them.
Glad you could save that one!!! =D I agree, it should be a crime to destroy these old systems.
Uwaterloo. That's cool to see. Got my undergrad there.
Wow that was my first ever computer :) my farther bought it brand new back in the early eighties :) I had Omega race, Tornado, Sargon II Chess and Jupiter Lander.
Excellent vid! Have just ordered the same ram expansion you have there, I can't believe how reasonably priced :-) $68AUD around 35 quid inc postage :-) huge cheers from me on the suggestion, and thanks for the vid!
Thanks =D No worries! These days you can also get the "Penultimate Cartridge" from thefuturewas8bit. That provides a load of cart functionality, plus even more RAM.
Yeah, I saw Dave (The8BitGuy) did a good review on them, man my other half is going to start throttling my neck with the stuff I'm doing on the retro machines, I've just done a SCSI2SD on the GVP 500-HD+ I had laying around, recapping old C64's, although I've gotten the kids involved, my 12 year old daughter now gets the soldering iron out having a go, just wish we could get paid to do this daily instead of working :-)
Thanks for uploading this - very helpful info. also, kitty at 14:15
Jesus man, that C64 looks brand new, like me you clearly treat your stuff with respect and kid gloves, I recently had nearly every CD game I own lightly polished and they all look amazing now.
Keep up the cool and interesting vid's.
+9ElevenGamer Hehe, thanks =) Yes, it's in excellent condition this VIC-20 at the moment. When the replacement VIC arrives (from AliExpress) I will swap things around and put the good case and keyboard on the original version VIC. It's worth cleaning up your stuff and keep things in tip top condition.
It is always good to,see some proper vic20 surgery! ;)
MOS before Tremiel bought them out. Licensed the 6502 and their sister chips to other companies like Lockheed/ Rockwell International, Synertek, Western Digital Design, and even Hitachi and many others. They were 99% compatible across the board with few minor differences.
I've just pulled my old Vic20 out of storage. I did have an issue with it displaying anything, before it went into storage decades ago. I managed to get around it by passing the RF modulated signal through an aerial amplifier. Unfortunately, that dodge no longer seems to work. I did just buy a composite cable for it from eBay, to see if that would give me an output. No luck. :(
It could be a dead VIC chip - that's the most common failure in these. If you have a tape deck or disk drive, you could try loading something (blindly) to see if the tape starts moving when you press return after the load command. Or similarly, see if the SD2IEC or disk drive lights indicate activity after an attempt to blind load.
It can activate the Datasette. My parents weren't rich enough to afford the disk drive. :(
I've just ordered a motherboard of the same revision that is claimed to be working. I'll test that it is first. If so, I'll try swapping chips to get the original motherboard working. Failing that I'll put the replacement board in and use the other for spare parts. Assuming all goes well, I'll be putting heatsinks on the chips that are most prone to failure.
GadgetUK164 - Retro Gaming Repairs & Mods
It turns out it was the VIC chip. I'm using my original motherboard with the chip off the board I bought. The 'new' board has a dodgy power switch, despite claiming to be 100% functional! You don't happen to know if compatible switches can still be bought new? If I can replace that I'll buy another VIC chip for it.
I think I bent that first pin at 5:43, but the 2nd pin was bent from shipping :P
Another excellent video Gadget, I was about to attempt something sort of similar by modding a 1541 drive to use these newer Rockwell / WDC parts and removing the giant voltage regulators and transformer and replacing them with modern switching equivalents in an attempt to create the most bulletproof 1541 possible by reducing its internal heat production. I never even thought of the difference in the open drain IRQ you pointed out in the video so that'll certainly be something to watch out for in my attempt. Maybe the real test for these 6522 chips is how well they will function in a 1541 thats been parallel modded, but its nice to know with a tiny mod they are almost nearly drop ins for a Vic 20. Cheers!
+aphexteknol You should be fine if you go for the W65C22N. The N suffix parts are NMOS compatible, and don't have the IRQ pin differences. I've used lots of those with no problems, also lots of Rockwell R6522P, so I don't know what the problem was.
+Dave Curran Good to know. As I understand it however, most various 65C02 CPUs however aren't fully (undocumented) opcode compatible with the original NMOS part however. Certain fastloaders are rumored to utilize them so its an issue for 1541s if you want 100% compatibility. Supposedly some or all Rockwell R65C02P chips are, but I haven't dug into the issue deep enough to start ordering parts just yet. The bulletproof 1541 is an idea I've had kicking around for ages, maybe I'll start getting serious about it just to see what works and what doesnt.....
+aphexteknol I have found the R6502P works better than the R65C02P in some cases, but I use both. I don't use the W65C02S as that is a bit too different. I did plan to update my 6502 ROM/RAM board to use the 65C02S in a surface mount part, with the various mods included, but haven't bothered as yet as there still seem to be good supplies of R6502P.
+Dave Curran Thanks again for the helpful information. Also, thank you for the work you put into your blog. It's excellent reading material for Commodore junkies such as myself. Take care.
Great video! what's the source for the disk images with the cart and loader?
Thanks! I think it came from thefuturewas8bit website!
W65C22S works without any "mods", its a 100% compatible replacement for MOS6522.
Edit: I just tested Dig Dug with the W65C22S and it works great.
Yeah, I am not sure which IC I used here but mine did need the mod - wouldnt work without it properly.
WDC makes brand new replacements for 6522. $11 USD.
pooyan was awesome.....i loved that game
Yeah =D The VIC-20 version is great too!
the vic was my first computer at age 12. i couldnt afford a c-64 at the time..they were still like 600$ then. so i had to wait a year or 2. but that gave me time to learn to program....my dam parents never told me you could BUY GAMES...so i had to write my own..it was literaly like 2 -3 years before i got a store bought game,
and it wasnt untill i was 14 ..and got a c-64 and two 1541 drives...and a copy of 1541 backup. that the piracy really began. got i loved my action replay cartridge. taught me how to crack games..lol.
ill never forget the sound that..the hard drive errors made...the ones used for copy protection....such a horrid idea
I have used the Rockwell R6522AP VIA's in a VIC-20 without having to do any modifications. In the video, it shows that Dig Dug wouldn't load, but mine works fine. I'm not loading it from a Penultimate, but from a Final Expansion 3 cartridge. Is there a more comprehensive test to find any possible incompatibility? Also, my VIC-20 diagnostic harness and tests run flawlessly.
It depends how it is loading - if loading from Cartridge it will be OK! The issue arrises when using a disk drive. It may also depend on which 6522 it really is - some of the Rockwell ones are WD etc and vice versa - they relabel them!
thanks for sharing m8!
You didn't have Poo Yan on the c64? It's a classic!
Hello Choplifter, it's been a while. :) Dig Dug does look pretty good, the Defender seems a bit less smooth than it should be, though I'm sure it surpasses the VCS version.
+MarkTheMorose Yes - Defender is a bit blocky in movement, but it plays pretty well!
Very interesting regarding the difference in the hardware layer of the IRQ pin. Out of interest I looked at the schematics and I couldn't find any other device driving the NMI (Interrupt line for the second 6522), so it puzzles me why the new WDC ic won't work with actively driving the NMI line high, because it looks like it is the only one driving that line... Anyway, very nice mod though. BTw do you have a inline power meter ? You should see a significant power saving from using that cmos device I read :)
+bwack I've read that the NMI line can take too long to transition - don't know how accurate that information is? Seemingly (I really should check with logic probe and scope) when the IRQ pin is low, the diode switches due to forward bias from the pull up on the NMI pin on the CPU, then when the IRQ goes high, the diode is reverse biased, which presumably means it goes high impedence and which point the NMI goes low? I would have through the pull up makes it high still - I am still a bit puzzled as to how this is working... I really should test it later to see exactly how its working.
+bwack Regards power - yes, I thought about that yesterday - I will connect the meter up at some point to see how much power is saved =D
+GadgetUK164 yes. When the diode is reverse biased (IRQ high) the pull up ensures that NMI go high. I guess you can say that the diode converts the outputstage into wired-OR and eliminates the pull-up network in the ic that the original ic doesn't have. It was the same situation in the 1541C drive. A socket could take a 7406 as is, but also there is a footprint for a diode in case 7404 is used.
+GadgetUK164 btw. What type of diode is it ? I read somewhere it should be a Schottky type diode for low forward voltage.
+bwack I think it's more important at higher clock speeds. I am using 1N4148 and it's working fine, I do have some BAT85's I could swap it out for if required.
Odd. I am looking at the data sheet of the MOS 6522 and Rockwell 6522* and the IRQ pin should behave identically. Your discussion is short on details. Do you think your Rockwell is a relabeled W65C22S? That's the VIA with the "different" IRQ. The W65C22N is the correct match for the MOS 6522.
This is direct from WDC "...some customers have had to use a diode in series with the IRQB output when using the W65C22S in their systems that had Wire-ORd interrupts." Your Rockwell 6522 behaves like a WDC W65C22S.
Good to know there are non-spec Rockwell 6522's out there. I have a tube of Rockwell 6522P VIAs. I hope I don't have to mod every one of them.
Yes, I think its a relabeled W65C22S! Goes to show you cannot trust anything from AliExpress!
@@GadgetUK164 Agreed. I have 5 Rockwell 6522P's I recently purchased NOS here in the US. I am hopeful I didn't get relabeled chips. They all say 9110 (10th week of 91?). But they all appear to never have been installed. Cheers!
Great vids as always! I picked up a vic20 bundle at a bootfair a while ago. Weird thing is that the keyboard only responds on a few keys but after power cycle different keys work....? I've had a poke about inside, it looks very clean. Have you heard of similar problems? maybe a chip issue? I may try reflowing solder points.
Hi. Do you have the older or newer motherboard? Might be a wonky power switch. Check voltages.
+bwack older 2 pin power so older model I think. thanks for replying :-)
+The Great Jonzini try swapping the two 6522's around, the one that does the keyboard (nearest the connector) may be faulty. Or it could be a RAM fault, those early large board ones are stuffed full of 2114s.
+Dave Curran I was going to suggest the same thing! Sounds like a 6522 issue =)
+bwack That's a good point - reminds me very much of your recommendation on one of my C64 videos when I had random input issues, which ended up caused by the 5v level being as low as 4.6v. Incidentally, if using a C64 PSU like I am here, you will see around 4.6v with clean power socket and switch... The VIC draws a lot more current and the voltage does drop as a result. I must get a beafier PSU at some point soon.
the video chip output is incredibly sharp, how did you manage to get a such clear picture?
I've done a mod to both of my VIC-20's (both the original model and cost reduced version - same mod to both). I think it was this video:- ruclips.net/video/h79nJFhbOIQ/видео.html
Where do I get the processor and chips online?
I've recently purchased 2 vic 20's and commodore 64 in the boxes. All in excellent condition. One vic 20 is disassembled with some of the old chips removed and looks like some new chips are on a foam pad in the box but the guy apparently never got around to putting them in. I'm not sure what I'm doing I've never installed a chip like these before any thing I should know about putting them in or taking them out that might make it easier or prevent me from damaging the chips? Also, one of the vic 20's is made in west germany and has gray colored keys which I've not seen before on a vic 20. I have an early vic 20 too that has a square power supply port so I'm curious about what power supply it uses. Great video and I subscribed.
+Nesmaniac Thanks! I am just about to upload another video on the one with the 2 pin power socket - I've modified mine to accept a 12v DC input (which can easily be reverted, so it's not damaging the VIC-20). With regards to chips - it's important that the correct chip is placed in the correct socket, not all chips have their power inputs on the same connections etc. So do make sure you are putting the correct chip into a socket before you power it up, and also check any other chips already in sockets to make sure they aren't the wrong way around or in the wrong spots. There's a semi circle marking on one end of the chip top, that indicates pin 1. The board will have a white outline of the chip drawn in the silk screen (usually covered mostly by the socket), but you can hopefully see from the socket or the white silk screen marking where that semi circle is marked, so you can line the chip up the correct way around.
Where did you get the RAM Expansion Unit from?
Off eBay at the time! You can buy RAM and ROM carts (Penultimate card is a good example) from Tynemouth Software or thefuturewas8bit.com.
DoeS it run without the CIA‘s?
Honestly not sure - I will check that soon when I work on a few VIC-20 boards!
Please, active subtitles, I am spanishman