Thank you for all your videos over the years. You have motivated me to repair my C64 that I have owned since the 1980s. I have determined that the chip that controls the keyboard has partially failed .. it is the MOS 6526. Digikey has over 700 2x20 sockets, and I can't tell which one I need - can you please advise me? Also, can you point me to a trustworthy source for the IC chip? Thank you in advance for your time, sir. EDIT: Also, where can I get a diagnostic harness and ROM cart?
The issue with SID chips is not the filter, it is the use of combined waveforms. (filters however can vary significantly in shape/gain/cutoff frq etc..) Music that uses combined waveforms will have differing results on different 6581s (8580's don't have this issue), anything from works properly through glitchy noise to no output at all. This does not mean that the SID is faulty, as long as it can produce all the individual waveforms as per the spec sheet, then the SID should be considered within spec. It is the demo/game music that is out of spec for using an unsupported mode. (this mode is supported by the 8580) Run the following program & record the output with something like Audacity. Test and record a number of chips, then load all the waveforms back in and compare them against a 8580 as baseline. Now you will be able to SEE the difference between the chips waveforms, and no longer have to subjectively guess what is going on. 10 poke53280,0: poke53281,0 50 print"“ disable screen y/n" 60 input b$ 70 if b$ ="y" then goto 100 80 if b$ ="n" then goto 115 90 goto 50 100 poke53265,11 115 print "“šqsid test - mod by ash in 2012" 120 v(0)=54272:v(1)=54279:v(2)=54286 130 poke54296,15:fori=0to2 140 pokev(i)+3,8:pokev(i)+1,0 150 pokev(i)+5,8:pokev(i)+6,198:next 160 fora=16to128step16:fori=0to2 165 print "channel =";i+1;" waveform =";a 170 if a>64 then pokev(i)+3,0 180 pokev(i)+4,a+1 190 forf=0to254step2:pokev(i)+1,f:nextf 200 pokev(i)+4,a:forw=0to200:nextw 210 pokev(i)+4,8:pokev(i)+1,0 220 nexti,a:a=1 230 fori=0to2:pokev(i)+1,255 235 print "channel =";i+1;" filter mode =";a 240 poke54296,(a*16)+15:poke54295,2^i 250 pokev(i)+4,129 260 forf=0to255:poke54294,f:nextf 270 pokev(i)+4,136:nexti 280 a=a*2:if a
@@moshly64 I kind of feel that's like saying a 6502 that won't run unrecommended instructions properly isn't faulty as long as it can run the documented ones correctly. That's simply not the case. Just because the designers didn't realize the SID could do things not documented doesn't mean those features can't be expected to work. And when they stop working it is a failure. There is plenty of variance from one 6581 to another but they generally all work in a similar way with similar and predictable results.
@@adriansdigitalbasement I'm just worried that people too easily write off SID chips as faulty when it is just different outside of spec. I found that what tends to happen is that the extra added waveform sounds only occur on 1 or 2 channels, the channels that it happens on is very inconsistent. It could be just ch1 or ch1 & 3 or ch2 & 3 etc..etc.. The song can 'sound' odd depending on what channel is using mixed waveforms vs what the chip can actually do on each channel. This effect is actually frequency dependent and effects the gain. A channel can be 100% gain at 1000Hz and 0% at 1001Hz, this envelope shape of the frequency sweep is what makes each channels mixed waveforms unique. I tested around 10 chips and found this out with the above program. None of the 6581 chips I tested (bar the 8580's) worked properly on all 3 channels. I think the best use for SIDs you find don't sound correct but still function to the basic spec, is to use them as a second channel in a fake stereo configuration. If you know what the differences are then you can pair complementary chips. I uploaded one of the test .sid songs I did back when to my channel if you want to take a listen & compare, 4 SID chip revisions. I also found some pic's of my tests. I'll email them to you if you like with a better explanation.
"I feel like if a hobbyist did this, they wouldn't have bothered putting the RF shield back on. Because it's a lot of work and doesn't do anything." If that hobbyist happened to be me, that RF shield would ABSOLUTELY go back on. As a ham radio operator, I detest the pollution of our airwaves with electronics not having the proper shielding. All you're doing by throwing away these RF shields is making the next guy down the road have to fabricate a new one.
The RF shield definitely did something. These computers operated right around the same frequencies as broadcast TV's on the era. Running one of these while the analog TV was on, the computer would interfere with the TV something fierce. I had a TRS-80, and even though the case was shielded, if messed up the family TV to the point i wasn't allowed to be on my machine when the rest of the family wanted to watch TV. Granted, nobody watches broadcast TV anymore, and even if they did, digital tuners are probably immune to the interference. But back in the day, that RF shielding was required by law.
@@jeromethiel4323 I'm not preparing a computer in 1982, but 2024. It does nothing for the operation or reliability of the computer and if anything, it makes it more unreliable, trapping more heat inside. Today all these LED bulbs and inverters and switching supplies are unshielded and spewing tons of EMI and RF, so in common vernacular, an RF shield on a C64 is now useless.
@@adriansdigitalbasement That's just not true. Amateur radio operators will tell you how annoying QRM is. Yes, there's all sorts of low-quality crappy power supplies that get imported that don't meet specifications for conducted emissions, but that's not really a good reason to remove RF shielding on other electronics! Quality, UL-listed power supplies have to meet EM noise requirements. Both conducted and transmitted interference are tested and must be below certain limits. We already have to deal with the extreme interference caused by those home powerline Ethernet systems, it would be nice if people took a less lax attitude toward RF interference.
@@AureliusRFYI, I am a licensed amateur radio operator as well. Complaining about a 1982 Computer that will hardly ever be used is beyond silly. Especially when other machines like the 1981 VIC-20 had no RF shielding at all. Should I always operate my VIC-20 in a faraday cage? My Apple II+? TRS-80 model 1? I could go on. The FCC started to push these rules because they knew there would be tens or hundreds of millions of computers operating all day all across the country... And back then TVs were hooked up with twin lead and AM radio use was still prevalent, they wanted to try to keep things under control. I know it's annoying dealing with interference while DXing on HF, but one C64 is a literal drop in the entire ocean of what you already have to deal with. It will never move the needle in any measurable way. I can't pick up AM broadcast radio in my basement due to all the interference from everything else.... My unshielded 8 bit computers have nothing to do with that. I think ONE machine turned on for 20 minutes once and a while is 100% inconsequential, in light of what I mentioned, the millions of SMPSs. How many C64s do you think are in use at any one time in my entire state?
I love Adrian's demeanor and patter while troubleshooting and repairing, but as a radio geek, Im ready to fight about his attitude toward the RF shielding ;)
A buddy of mine used a 64 for orbit prediction for EME back in the 80's, that shielding really just don't matter. If your doing something RF noise sensitive you just got to shut that thing off.
Right? I don't understand why he throws away a vital part of each system. Sure it's a cheap RF shield, but it's not like you have to look at it when the computer is assembled. And I'm pretty sure he's thrown away those lovely stamped steel ones from the later machines too.
The shields create additional heat buildup for the motherboard. I would rather have a little (very very little) additional RF interference then no RF because the chips fried. (and after 40 years it does not take much to push them over the edge.)
@@networkg Then install a fan. I designed a 3d printable fan shroud that fits in breadbin c64s. It doesn't modify the case, doesn't introduce any noticeable noise, and makes use of the vents in the top half of the shell.
A little more than half my 6581 C64s sound like that and have already sounded like that 20 years ago. The HVSC SID Player in the old revision that still ran on Windows 98 sounds similar to the "broken" SID chip. The filters are a lot stronger and tend to distort, especially when running on the edge. There were even SID tunes adapted (back in the mid-80s!) to sound good on these SIDs.
@@senilyDeluxe Nearly every batch of SID chips produced has slightly different behaviour. The chipsynth project went DEEP into categorizing and collecting the different sounds: ua-cam.com/video/pePq68HaI7M/v-deo.html
Those SID synth chips are just magical, I mean the satisfaction and good mood they give me when I hear them 'singing' at the end of every repaired C64 tests is just like nothing else! Surely there are much more capable synthesizers and samplers even back in the day, but there is something about the tones those chips are producing i cannot explain, it's if like a toy music box could play complex heavy synth techno music i believe that would be the resulting sound. Their sound is toyish cute, not perfect with a very decent bass tone and an electric atmosphere... Great video as always, cheers from Greece, keep up!
The thought occurred to me while watching this that maybe his "donor boards" are computers he fixed in a previous episode and he just keeps swapping parts back and forth because he enjoys it and wants to make content.
Oh yeah the content I originally came to this channel before besides the desk station tyne video. I’ve never touched a single c64 despite my almost 40 years on this earth (I got to my computer nerdom later in life) but I feel confident I could diagnose and repair one effortless after watching you do it so much.
The second C64 runs the clock twice as fast compared to the first one. The music changes at 15 seconds at 19:27 and the same change happens at 30 seconds at 28:22
Don't throw away the rf shields. They are there for a reason. Today there is even more radiation around your 64 than back then. Besides the functional part, they are also a part of the machine and make it complete.
Dude...the RF shield wasn't there to protect your c64 from "radiation". It job was to protect other devices from interference caused by the C64's rf emissions. There isn't a functional part for those rf shields in our time(except if there is a radio broadcasting studio near you or in later C64c which were used as IC heat sinks. Small aluminum heat sinks work much bette). In addition to that , the upper rf shield part acts as heat traps and the lower soldered part only delays you from your repair works and mods. You should throw them out of the case...yesterday.
@@nickolasgaspar9660 Dude... interference can be picked up by the c64 coming from more devices than ever before. If it can create "radiation" it can also pick up "radiation".
@@nickolasgaspar9660 There are still a LOT of people using the RF spectrum if you hadn't noticed. Our attitude shouldn't be "oh, modern devices can resist interference, so lets just pollute the airwaves, who cares?". Amateur radio operators in particular deal with man-made interference on a regular basis and it's extremely frustrating.
Hell Yeah! C64 videos!!!!!, i don't know why but i can't stop watching your C64 videos! i probably watch them ALL, when you don't do one in a while i search 5 year old and watch them again xD
The weird thing I like about the C64 is that the cause of failures are varied - so many things can go wrong that troubleshooting/fixing videos are always interesting. The Apple IIe on the other hand (assuming no catastrophic damage) is more of a "does it have MT ram" or "is one of the cards bad" or "RIFA!!!" and... uh... that's it. Congrats to Apple for making a very reliable machine, but the C64 resulted in a lot more YT content and clever solutions.
Recently fixed a C64 rev A that booted to Ready but with no cursor and no working keyboard input. Fixed it by reseating the kernel ROM with some deoxit. Of course, that was the last thing I tried. Thanks for all the educational videos! Rock on!
Hey Adrian, great video. I love your C64 repairs. As to the PLA in machine #1, the 8411 number on sticker on the PLA isn’t a date code. According to The C64 PLA Dissected by Thomas ’skoe’ Giesel that can be downloaded on the Internet the 8411 is a four digit hex number checksum. This is a very early Signetics PLA chip that predates the 906114 MOS chip.
Anyone ever think about how these machines have kind of a crazy lineage? Somebody would have bought it in a store, and started its life. And 40 years later, it somehow managed to avoid landfills or recyclers, to wind up on an Internet that wasn't even close to imaginable when this was new. It just had the million perfect events to wind up in the hands of Adrian this far out. And in most cases, one will never know who the original owner may have been, what uses it may have had... or how many hands it may have been passed around to.
I really enjoy these videos. I know it is almost like a "rerun" but there are many shows I watch over and over again because I just LIKE them. Or maybe... it would be a better example to say this is like watching a game of football or baseball. Same game, different events within.
I don't love C64s (not that much anyway) but I still love watching your interesting videos. You've had a lot of c64 and apple2 repair videos but I would love to see some more spectrums, orics, dragon 32s, zx81s, amstrads all of which were very popular in Europe.
If you like 8 bit computers and you like repair videos and you like the Commodore 64 then this video is for you.... This video is for me. Great video. Great head boppin. Head boppin in C64 videos is required.
5:46 - Simple. Two more holes were added on the jack, but they *don't* conflict with your 5-pin plug! It's backward-compatible! Maybe all that was available then were 7-pin connectors and they just left those 2 holes unconnected. 7:22 - I *may* be correct! I don't see anything connected to those extra leads, put some of the existing pins have been repurposed. (?)
I cannot wait to possibly see you and a bunch of other of my favorite creators at VCFMW this year! I’ve been watching a lot of these people for over 10 years now.
I agree. It's not like that is the last Rev A board out there or anything. If it was a super rare variation or model that might change my mind. Also IF one was to say it needs ro be reverted then the RF shields need to go back on 😉
@@kelvin1316 recon that is what makes this world great is that everyone sees things a little differently. To me IF it was the only one left or something and I could get it back to 100% original condition and functional I would probably do it.
Thanks again for all the great videos! Also I wanted to mention: I have a VIC-20 that has chips with the exact same yellow paints dots on them. I believe that's a factory thing. They look *exactly* like what you have - same size and color!
Back in the mid 80s, I ran into a guy in Toronto, that was selling repaired, warranty returned C64s. I bought a couple of them for my kids, so they could both have their own computer. I can't guess how he got them, but he seemed to have an unlimited supply. I also bought a couple of repaired mother boards, and replaced the boards in the Vic20s that I had. I think I still have one of those stashed away somewhere as well.
As an audio guy, I'd love a C64 racked up in my studio rack, with a midi hookup to use the analog synth somehow. I just love the way the C64 synth sounds. I never had a C64, so I don't have the nostalgia many people do for that sound, and I STILL think it sounds so cool. I'd love to make some bass tracks, and synth beds in some of my music using those sounds.
The other thing about those REV A board is they have a trimmer (R25) to set the chroma level. Later revs that use the modulator don't have that adjustment. The assembly line workers were told to turn it up until they saw color. Sometimes they would just turn it all the way up, making the color far more saturated than it should be and swamping out luma.
Thanks for all the great videos! That broken SID sounds like the low pass filter might be messed up. In any case it also sounds really cool. Like that failure mode is *fire*! If it were me I'd save it just for sounding cool and maybe sample it before it finally dies! The SID is so cool for having analog filters and it's too bad none of the SID replacement have analog filters because you can't actually pass input audio through them like you can with an original SID. At least as far as i know when it comes to replacements you can actually buy. In any case you rock!
The modification on the original 64 was quite common here in Argentina. The Drean Commodore 64C featured the older Rev A motherboards with the exact same modification. Although they resembled the American 64C on the outside, internally they housed the older, modified Rev A motherboards.
Tip: Test the SID chips with Plogue's old SIDBench program. Even chips such as the odd one here will mostly have working filter sweeps. As a bonus, you get to hear the combined waveforms, and these vary a lot between 6581s.
If you weren't already aware, paralleling resistor values reduces the over all load value by half. So if you wanted to you could do quick math to figure out what the intended value should be, and add a resistor that reduces the whole load to that value. It can get complicated when you start doing series parallel resistor circuits. lol
My Rev A board has the same video modification. The wires even look to be the same, with the Green and Gray wire and glue. I am fairly certain though you ran across another of these boards awhile ago in a video, and I think the wires were not the Green and Gray ones.. but my memory is not perfect. It is also fully socketed, and the socketed chips are from 1984 although an 83 kernel rom, while the chips soldered to the board are from 82. The CIAs in my board are 3 weeks older than yours though..
Even as a hobbyist I would absolutely have soldered the RF shield back. If this was a customer's machine, I would make sure that was done as that is what I assume the customer would expect.
It's so funny how you started on the first machine because I was thinking I heard somewhere exactly what you said that Commodore would populate older boards later and then you said it, it got me thinking and I think it was you that said it in a much older video I saw before. 🤣
Could you imagine the excitement of the engineer who made the call about the cardboard backed RF shield when you consider the cast armor used in the Atari 400 and 800.
It's great fixed all 3 c64 computers. it's worth to work on other spare c64 circuit board, and doing a preventive maintenance for all working c64 computers you have. Anyway, It's nice to heard the 8 bit dance party music again.
@41:31 it seems that the ring modulation sound is missing. I don't know if it is the file, the player or the specific SID, but I'm quite sure it's wrong.
So some of C64's custom chips have changed during the system's life time resulting to incompatibilities between models and ICs. Different number of pins and sizes, different operating voltage. This is also true for some later CPC and Speccy models. The one line of computers that you can literally get an IC from the first model and put it on the latest is the 8bit Atari. The only hiccup I can remember is that some early 800/400 don't use Sally chip, since they use the original 6502 and the relative circuit responsible for halting the CPU can be found on the CPU board.
Maybe the keyboard-connector pins left those scratches on the first board? That first attempt at playing Cybernoid sounded like what happens when my cat stands on the play/pause button while I'm watching a video or listening to music! The improperly functioning SIDs could be fun for a synthesizer build that played off of the issues, especially if multiple were used. Makes me want to mine out my old broken Commodore computers and fix them up!
Leave the DIN connector mod in place. There's no need to restore to original DIN, as there are plenty of those and it's a nifty thing to have an old mod that modernized to work with Chroma/Luma.
That Rev A board was Frankensteined in 84 and replaced the case. I would drop it back. I doubt the video signal is improved with the bodges. I have a C64 that is all socketed, and has yellow dots on it. I wondered if these were the ones the Commodore needed chips to complete or were warranty "refurbished" then sold as new. The one I had had never been opened before I got it. I got it from the original owner with the box.
The bodge wire "glue" looks like a product I know as wiretak This was a gel type superglue, which you glued the wires down with, then gave it a quick spray of activator to set it. They just seemed to have been a bit enthusiastic ion the application. Andy
Like the channel, but you need to reinstall the RF shielding, its there for a reason and the reason is to prevent noise on other systems, it saves the next person from looking at strange things crashing elsewhere.
I've maybe watched too many of these videos because I've never had a C64 and I've certainly never worked on one but when I saw the dead test pop up i thought "must be the KERNEL ROM then", then you said the same, and turns out, sure enough, it was the KERNEL ROM.
Ode to C64 @19:30 sounds perfectly fine, the filter curve is just a bit out of spec. Believe it or not, there are tunes out there that need chips like this one =) Try Xenophobe by Barry Leitch, especially tunes 2 (from 0:25) , 4, 7 and 8!
Hello🙂 did you come on issue when video from c64 on composite and svideo was darker than normal? My friend have this issue, we changed Vic and with my it's bright as it should be. Any ideas where we can pull it up? C64c short board.
Please, never stop making C64 repair videos. No matter how many you make I always like these the best. I WILL NEVER GET TIRED OF C64 REPAIR VIDEOS! You rock. 😘
Nice run-through as always, thanks for sharing. And indeed, it should be against the law not to have the 8-bit Dance Party tune played in all of your C64 vids! ;)
I'll try to save Adrian having to look this up as I recently had to figure this one out myself. It's just looking for signalling with two loopbacks. It sends a signal on one pin and looks for it to come back on another and does that with two pairs of pins.
Side note, on the 3rd machine, I did test the KERNEL ROM on the ZIF C64 and it is indeed just "dead"
Dead as a doornail
Dead as a drunk dump truck? 😂
I like that you can now get replacement ROMS that fit the socket and look like a "normal" ROM.
Thank you for all your videos over the years. You have motivated me to repair my C64 that I have owned since the 1980s. I have determined that the chip that controls the keyboard has partially failed .. it is the MOS 6526.
Digikey has over 700 2x20 sockets, and I can't tell which one I need - can you please advise me?
Also, can you point me to a trustworthy source for the IC chip?
Thank you in advance for your time, sir.
EDIT: Also, where can I get a diagnostic harness and ROM cart?
It is "Kernal", AFAIK.
The issue with SID chips is not the filter, it is the use of combined waveforms. (filters however can vary significantly in shape/gain/cutoff frq etc..)
Music that uses combined waveforms will have differing results on different 6581s (8580's don't have this issue), anything from works properly through glitchy noise to no output at all.
This does not mean that the SID is faulty, as long as it can produce all the individual waveforms as per the spec sheet, then the SID should be considered within spec.
It is the demo/game music that is out of spec for using an unsupported mode. (this mode is supported by the 8580)
Run the following program & record the output with something like Audacity. Test and record a number of chips, then load all the waveforms back in and compare them against a 8580 as baseline. Now you will be able to SEE the difference between the chips waveforms, and no longer have to subjectively guess what is going on.
10 poke53280,0: poke53281,0
50 print"“ disable screen y/n"
60 input b$
70 if b$ ="y" then goto 100
80 if b$ ="n" then goto 115
90 goto 50
100 poke53265,11
115 print "“šqsid test - mod by ash in 2012"
120 v(0)=54272:v(1)=54279:v(2)=54286
130 poke54296,15:fori=0to2
140 pokev(i)+3,8:pokev(i)+1,0
150 pokev(i)+5,8:pokev(i)+6,198:next
160 fora=16to128step16:fori=0to2
165 print "channel =";i+1;" waveform =";a
170 if a>64 then pokev(i)+3,0
180 pokev(i)+4,a+1
190 forf=0to254step2:pokev(i)+1,f:nextf
200 pokev(i)+4,a:forw=0to200:nextw
210 pokev(i)+4,8:pokev(i)+1,0
220 nexti,a:a=1
230 fori=0to2:pokev(i)+1,255
235 print "channel =";i+1;" filter mode =";a
240 poke54296,(a*16)+15:poke54295,2^i
250 pokev(i)+4,129
260 forf=0to255:poke54294,f:nextf
270 pokev(i)+4,136:nexti
280 a=a*2:if a
@@moshly64 I kind of feel that's like saying a 6502 that won't run unrecommended instructions properly isn't faulty as long as it can run the documented ones correctly. That's simply not the case. Just because the designers didn't realize the SID could do things not documented doesn't mean those features can't be expected to work. And when they stop working it is a failure.
There is plenty of variance from one 6581 to another but they generally all work in a similar way with similar and predictable results.
@@adriansdigitalbasement I'm just worried that people too easily write off SID chips as faulty when it is just different outside of spec.
I found that what tends to happen is that the extra added waveform sounds only occur on 1 or 2 channels, the channels that it happens on is very inconsistent. It could be just ch1 or ch1 & 3 or ch2 & 3 etc..etc.. The song can 'sound' odd depending on what channel is using mixed waveforms vs what the chip can actually do on each channel. This effect is actually frequency dependent and effects the gain. A channel can be 100% gain at 1000Hz and 0% at 1001Hz, this envelope shape of the frequency sweep is what makes each channels mixed waveforms unique.
I tested around 10 chips and found this out with the above program. None of the 6581 chips I tested (bar the 8580's) worked properly on all 3 channels.
I think the best use for SIDs you find don't sound correct but still function to the basic spec, is to use them as a second channel in a fake stereo configuration. If you know what the differences are then you can pair complementary chips.
I uploaded one of the test .sid songs I did back when to my channel if you want to take a listen & compare, 4 SID chip revisions. I also found some pic's of my tests. I'll email them to you if you like with a better explanation.
"I feel like if a hobbyist did this, they wouldn't have bothered putting the RF shield back on. Because it's a lot of work and doesn't do anything."
If that hobbyist happened to be me, that RF shield would ABSOLUTELY go back on. As a ham radio operator, I detest the pollution of our airwaves with electronics not having the proper shielding. All you're doing by throwing away these RF shields is making the next guy down the road have to fabricate a new one.
The cardboard ones? Meh
The RF shield definitely did something. These computers operated right around the same frequencies as broadcast TV's on the era. Running one of these while the analog TV was on, the computer would interfere with the TV something fierce. I had a TRS-80, and even though the case was shielded, if messed up the family TV to the point i wasn't allowed to be on my machine when the rest of the family wanted to watch TV.
Granted, nobody watches broadcast TV anymore, and even if they did, digital tuners are probably immune to the interference. But back in the day, that RF shielding was required by law.
@@jeromethiel4323 I'm not preparing a computer in 1982, but 2024. It does nothing for the operation or reliability of the computer and if anything, it makes it more unreliable, trapping more heat inside. Today all these LED bulbs and inverters and switching supplies are unshielded and spewing tons of EMI and RF, so in common vernacular, an RF shield on a C64 is now useless.
@@adriansdigitalbasement That's just not true. Amateur radio operators will tell you how annoying QRM is. Yes, there's all sorts of low-quality crappy power supplies that get imported that don't meet specifications for conducted emissions, but that's not really a good reason to remove RF shielding on other electronics! Quality, UL-listed power supplies have to meet EM noise requirements. Both conducted and transmitted interference are tested and must be below certain limits. We already have to deal with the extreme interference caused by those home powerline Ethernet systems, it would be nice if people took a less lax attitude toward RF interference.
@@AureliusRFYI, I am a licensed amateur radio operator as well.
Complaining about a 1982 Computer that will hardly ever be used is beyond silly. Especially when other machines like the 1981 VIC-20 had no RF shielding at all. Should I always operate my VIC-20 in a faraday cage? My Apple II+? TRS-80 model 1? I could go on.
The FCC started to push these rules because they knew there would be tens or hundreds of millions of computers operating all day all across the country... And back then TVs were hooked up with twin lead and AM radio use was still prevalent, they wanted to try to keep things under control.
I know it's annoying dealing with interference while DXing on HF, but one C64 is a literal drop in the entire ocean of what you already have to deal with. It will never move the needle in any measurable way. I can't pick up AM broadcast radio in my basement due to all the interference from everything else.... My unshielded 8 bit computers have nothing to do with that.
I think ONE machine turned on for 20 minutes once and a while is 100% inconsequential, in light of what I mentioned, the millions of SMPSs. How many C64s do you think are in use at any one time in my entire state?
I love Adrian's demeanor and patter while troubleshooting and repairing, but as a radio geek, Im ready to fight about his attitude toward the RF shielding ;)
A buddy of mine used a 64 for orbit prediction for EME back in the 80's, that shielding really just don't matter. If your doing something RF noise sensitive you just got to shut that thing off.
Everyone BUT a radio tech has similar attitudes towards material sheilding
Right? I don't understand why he throws away a vital part of each system. Sure it's a cheap RF shield, but it's not like you have to look at it when the computer is assembled.
And I'm pretty sure he's thrown away those lovely stamped steel ones from the later machines too.
The shields create additional heat buildup for the motherboard. I would rather have a little (very very little) additional RF interference then no RF because the chips fried. (and after 40 years it does not take much to push them over the edge.)
@@networkg Then install a fan. I designed a 3d printable fan shroud that fits in breadbin c64s. It doesn't modify the case, doesn't introduce any noticeable noise, and makes use of the vents in the top half of the shell.
"It does not sound like this" - yet the C64 still somehow sounds awesome even broken.
A little more than half my 6581 C64s sound like that and have already sounded like that 20 years ago. The HVSC SID Player in the old revision that still ran on Windows 98 sounds similar to the "broken" SID chip. The filters are a lot stronger and tend to distort, especially when running on the edge. There were even SID tunes adapted (back in the mid-80s!) to sound good on these SIDs.
@@senilyDeluxe Nearly every batch of SID chips produced has slightly different behaviour. The chipsynth project went DEEP into categorizing and collecting the different sounds: ua-cam.com/video/pePq68HaI7M/v-deo.html
Those SID synth chips are just magical, I mean the satisfaction and good mood they give me when I hear them 'singing' at the end of every repaired C64 tests is just like nothing else! Surely there are much more capable synthesizers and samplers even back in the day, but there is something about the tones those chips are producing i cannot explain, it's if like a toy music box could play complex heavy synth techno music i believe that would be the resulting sound. Their sound is toyish cute, not perfect with a very decent bass tone and an electric atmosphere...
Great video as always, cheers from Greece, keep up!
How many broken C64 do you have?
Adrian: Yes
There's a video he did when Roman from Epictronics channel came by and there must have been 20 of them in a pile!!!
The thought occurred to me while watching this that maybe his "donor boards" are computers he fixed in a previous episode and he just keeps swapping parts back and forth because he enjoys it and wants to make content.
Commodore had a large number of broken machines that came back under warranty that were reworked and resold.
The Plexus has been sitting in the background, silently staring at Adrian's back, willing him into doing more work on it.
At this point, the Plexus is behaving passive aggressive, almost manipulative like in a co-dependent relationship 😂😂😂
Oh yeah the content I originally came to this channel before besides the desk station tyne video.
I’ve never touched a single c64 despite my almost 40 years on this earth (I got to my computer nerdom later in life) but I feel confident I could diagnose and repair one effortless after watching you do it so much.
The second C64 runs the clock twice as fast compared to the first one. The music changes at 15 seconds at 19:27 and the same change happens at 30 seconds at 28:22
Don't throw away the rf shields. They are there for a reason. Today there is even more radiation around your 64 than back then. Besides the functional part, they are also a part of the machine and make it complete.
Dude...the RF shield wasn't there to protect your c64 from "radiation". It job was to protect other devices from interference caused by the C64's rf emissions.
There isn't a functional part for those rf shields in our time(except if there is a radio broadcasting studio near you or in later C64c which were used as IC heat sinks. Small aluminum heat sinks work much bette). In addition to that , the upper rf shield part acts as heat traps and the lower soldered part only delays you from your repair works and mods. You should throw them out of the case...yesterday.
@@nickolasgaspar9660 Dude... interference can be picked up by the c64 coming from more devices than ever before. If it can create "radiation" it can also pick up "radiation".
@@nickolasgaspar9660 There are still a LOT of people using the RF spectrum if you hadn't noticed. Our attitude shouldn't be "oh, modern devices can resist interference, so lets just pollute the airwaves, who cares?". Amateur radio operators in particular deal with man-made interference on a regular basis and it's extremely frustrating.
Hell Yeah! C64 videos!!!!!, i don't know why but i can't stop watching your C64 videos! i probably watch them ALL, when you don't do one in a while i search 5 year old and watch them again xD
The weird thing I like about the C64 is that the cause of failures are varied - so many things can go wrong that troubleshooting/fixing videos are always interesting. The Apple IIe on the other hand (assuming no catastrophic damage) is more of a "does it have MT ram" or "is one of the cards bad" or "RIFA!!!" and... uh... that's it. Congrats to Apple for making a very reliable machine, but the C64 resulted in a lot more YT content and clever solutions.
Recently fixed a C64 rev A that booted to Ready but with no cursor and no working keyboard input. Fixed it by reseating the kernel ROM with some deoxit. Of course, that was the last thing I tried. Thanks for all the educational videos! Rock on!
Hey Adrian, great video. I love your C64 repairs. As to the PLA in machine #1, the 8411 number on sticker on the PLA isn’t a date code. According to The C64 PLA Dissected by Thomas ’skoe’ Giesel that can be downloaded on the Internet the 8411 is a four digit hex number checksum. This is a very early Signetics PLA chip that predates the 906114 MOS chip.
Appreciate you keeping these c64s alive
Anyone ever think about how these machines have kind of a crazy lineage? Somebody would have bought it in a store, and started its life. And 40 years later, it somehow managed to avoid landfills or recyclers, to wind up on an Internet that wasn't even close to imaginable when this was new. It just had the million perfect events to wind up in the hands of Adrian this far out. And in most cases, one will never know who the original owner may have been, what uses it may have had... or how many hands it may have been passed around to.
Now I have!❤ thanks
If you start repairing even older stuff we can move you upstairs to Adrian's Analog Attic.
I really enjoy these videos. I know it is almost like a "rerun" but there are many shows I watch over and over again because I just LIKE them. Or maybe... it would be a better example to say this is like watching a game of football or baseball. Same game, different events within.
I don't love C64s (not that much anyway) but I still love watching your interesting videos. You've had a lot of c64 and apple2 repair videos but I would love to see some more spectrums, orics, dragon 32s, zx81s, amstrads all of which were very popular in Europe.
If you like 8 bit computers and you like repair videos and you like the Commodore 64 then this video is for you.... This video is for me. Great video. Great head boppin. Head boppin in C64 videos is required.
5:46 - Simple. Two more holes were added on the jack, but they *don't* conflict with your 5-pin plug! It's backward-compatible!
Maybe all that was available then were 7-pin connectors and they just left those 2 holes unconnected.
7:22 - I *may* be correct! I don't see anything connected to those extra leads, put some of the existing pins have been repurposed. (?)
Great stuff man! Can't wait to see ya at VCF!
I particularly love your C64 repair videos so I am really happy you have released another. 😊
I love repair videos, those can be very useful for learning certain skills. Video guides to software mod modern consoles tend to not be recommended XD
I cannot wait to possibly see you and a bunch of other of my favorite creators at VCFMW this year! I’ve been watching a lot of these people for over 10 years now.
I think mods that were done during its original lifespan should be left unless it’s causing major problems - it’s had a history!
I agree. It's not like that is the last Rev A board out there or anything. If it was a super rare variation or model that might change my mind. Also IF one was to say it needs ro be reverted then the RF shields need to go back on 😉
@@homeFall1 I'd argue even if it were a rare machine/board
@@kelvin1316 recon that is what makes this world great is that everyone sees things a little differently. To me IF it was the only one left or something and I could get it back to 100% original condition and functional I would probably do it.
I enjoy the fact that Adrian can still be surprised when repairing a breadbin C64
Thanks again for all the great videos! Also I wanted to mention: I have a VIC-20 that has chips with the exact same yellow paints dots on them. I believe that's a factory thing. They look *exactly* like what you have - same size and color!
That "Ode to C64" track was fire! Gonna go find it.
Back in the mid 80s, I ran into a guy in Toronto, that was selling repaired, warranty returned C64s. I bought a couple of them for my kids, so they could both have their own computer. I can't guess how he got them, but he seemed to have an unlimited supply.
I also bought a couple of repaired mother boards, and replaced the boards in the Vic20s that I had. I think I still have one of those stashed away somewhere as well.
Amazing these machines were - simple - addictive - timeless.. Thanks for your content.
It's funny you have extra 64 boards kicking around as backup, I have the same thing but it's extra NES motherboards hahaha
As an audio guy, I'd love a C64 racked up in my studio rack, with a midi hookup to use the analog synth somehow. I just love the way the C64 synth sounds. I never had a C64, so I don't have the nostalgia many people do for that sound, and I STILL think it sounds so cool. I'd love to make some bass tracks, and synth beds in some of my music using those sounds.
The other thing about those REV A board is they have a trimmer (R25) to set the chroma level. Later revs that use the modulator don't have that adjustment.
The assembly line workers were told to turn it up until they saw color. Sometimes they would just turn it all the way up, making the color far more saturated than it should be and swamping out luma.
31:54 - That's a buggy C64! :D
Thanks for all the great videos! That broken SID sounds like the low pass filter might be messed up. In any case it also sounds really cool. Like that failure mode is *fire*! If it were me I'd save it just for sounding cool and maybe sample it before it finally dies! The SID is so cool for having analog filters and it's too bad none of the SID replacement have analog filters because you can't actually pass input audio through them like you can with an original SID. At least as far as i know when it comes to replacements you can actually buy. In any case you rock!
The modification on the original 64 was quite common here in Argentina. The Drean Commodore 64C featured the older Rev A motherboards with the exact same modification. Although they resembled the American 64C on the outside, internally they housed the older, modified Rev A motherboards.
Tip: Test the SID chips with Plogue's old SIDBench program. Even chips such as the odd one here will mostly have working filter sweeps. As a bonus, you get to hear the combined waveforms, and these vary a lot between 6581s.
If you weren't already aware, paralleling resistor values reduces the over all load value by half. So if you wanted to you could do quick math to figure out what the intended value should be, and add a resistor that reduces the whole load to that value. It can get complicated when you start doing series parallel resistor circuits. lol
My Rev A board has the same video modification. The wires even look to be the same, with the Green and Gray wire and glue. I am fairly certain though you ran across another of these boards awhile ago in a video, and I think the wires were not the Green and Gray ones.. but my memory is not perfect. It is also fully socketed, and the socketed chips are from 1984 although an 83 kernel rom, while the chips soldered to the board are from 82. The CIAs in my board are 3 weeks older than yours though..
Even as a hobbyist I would absolutely have soldered the RF shield back. If this was a customer's machine, I would make sure that was done as that is what I assume the customer would expect.
like that one of the sid files is "koeleskab"(OE is for Ø) there in danish for "køleskab" aka English "refrigerator"
You don't install heat sink compound on the VIC2 chips when you reinstall the cover?
It's so funny how you started on the first machine because I was thinking I heard somewhere exactly what you said that Commodore would populate older boards later and then you said it, it got me thinking and I think it was you that said it in a much older video I saw before. 🤣
yeaahhh....c64 again...i love it. 😍😄
thank you very much dear adrian.
stay safe and healthy.
greetings from germany. 🙂
Hello Adrian, Great videos like always a big hello from Spain 😉👍🦾
Nice work. My first computer was a C64 in '82.
Could you imagine the excitement of the engineer who made the call about the cardboard backed RF shield when you consider the cast armor used in the Atari 400 and 800.
Wow, new lighting. I like it.
Love the C64 Repair Videos! -Mark.
I had an Atari 800xl but enjoy watching all the videos Adrian puts out.
this was realy relaxing and entertaining. i watched it while i am playing Golf ( PGA 2k24).Thank you.
31:54 Brand New? Insect crawling under the RF shield in the video!!
Those are some nice tunes. Are the sids available to dl somewhere?
It's great fixed all 3 c64 computers. it's worth to work on other spare c64 circuit board, and doing a preventive maintenance for all working c64 computers you have. Anyway, It's nice to heard the 8 bit dance party music again.
@41:31 it seems that the ring modulation sound is missing. I don't know if it is the file, the player or the specific SID, but I'm quite sure it's wrong.
So some of C64's custom chips have changed during the system's life time resulting to incompatibilities between models and ICs. Different number of pins and sizes, different operating voltage. This is also true for some later CPC and Speccy models.
The one line of computers that you can literally get an IC from the first model and put it on the latest is the 8bit Atari. The only hiccup I can remember is that some early 800/400 don't use Sally chip, since they use the original 6502 and the relative circuit responsible for halting the CPU can be found on the CPU board.
Maybe the keyboard-connector pins left those scratches on the first board?
That first attempt at playing Cybernoid sounded like what happens when my cat stands on the play/pause button while I'm watching a video or listening to music!
The improperly functioning SIDs could be fun for a synthesizer build that played off of the issues, especially if multiple were used.
Makes me want to mine out my old broken Commodore computers and fix them up!
Great video. I hope that you do a follow-up video on the keyboard that has peculiar issues.
Could the issue with that first machine's keyboard be that the shift lock was on? At 24:38 you can see the key is down.
31:53 I see you have an assistant.
Do you ever sell the extras? I never had a commodore before but if i get one id like it to come from someone like you so i know it works!
isopod at 31:54 has strong opinions about this home invasion
The number on the printed label on the PLA is not a date code, it's a check sum of the contents of the PLA.
Hey adrian thank you for all your great retro content. Can you tell me what sidplayer you use?
Focus on C64s and C128s ALL THE TIME ❤❤❤
I recently got two commodore 64s recently and i plan on using these videos to help me figure out why they are black screening
Leave the DIN connector mod in place. There's no need to restore to original DIN, as there are plenty of those and it's a nifty thing to have an old mod that modernized to work with Chroma/Luma.
That Rev A board was Frankensteined in 84 and replaced the case. I would drop it back. I doubt the video signal is improved with the bodges.
I have a C64 that is all socketed, and has yellow dots on it. I wondered if these were the ones the Commodore needed chips to complete or were warranty "refurbished" then sold as new. The one I had had never been opened before I got it. I got it from the original owner with the box.
the second machine was running faster on the music time. Is that a 50Hz model?
The bodge wire "glue" looks like a product I know as wiretak
This was a gel type superglue, which you glued the wires down with, then gave it a quick spray of activator to set it.
They just seemed to have been a bit enthusiastic ion the application.
Andy
Your 8-bit dance party is part of Bleass Samplewiz 2. No, I am not kidding. The scene version, v.1.5.1 and v.1.6.0.
donkey kong
Oh man, we’re goin’ old skool ADB, nice.
I’d love to see some 1351 mouse repair work, have one that I just can’t get to track correctly.
I think the mod @ 7:39 should not be removed as it was probably a common thing to do so you'd get S-Video output.
I'm liking this BEFORE I watch it ❤
Love the c64 videos!
I think that ODE to C64 song sounded pretty cool. Like a modern EDM mix. Or a TimeCop song.
Digikey and others sell a smps module that are drop in replacements.some 95 present efficient no heat.
There was a critter at 31:53
Like the channel, but you need to reinstall the RF shielding, its there for a reason and the reason is to prevent noise on other systems, it saves the next person from looking at strange things crashing elsewhere.
Adding Ode to 64.sid to my workout playlist!
The EasyFlash cart wasn't quite inserted right on machine one - check the video, it's a tiny bit diagonal.
I've maybe watched too many of these videos because I've never had a C64 and I've certainly never worked on one but when I saw the dead test pop up i thought "must be the KERNEL ROM then", then you said the same, and turns out, sure enough, it was the KERNEL ROM.
Interesting that the first boards says REV D on the back, and REV A on the front.
so the early board yes the MOS PLA is bad, on the 407 it's hit or miss but if you have a 425 it's usually pretty reliable.
16:47 Those cutters are made for max 1mm copper wires and everything else will destroy them ...
I love that there's a Sid file named koeleskab (fridge in Danish)..🙂
Doesn't take much to amuse me..🤔
Ode to C64 @19:30 sounds perfectly fine, the filter curve is just a bit out of spec. Believe it or not, there are tunes out there that need chips like this one =) Try Xenophobe by Barry Leitch, especially tunes 2 (from 0:25) , 4, 7 and 8!
@adriansdigitalbasement I love the look of your SID collection, is that from a public list or would you be willing to share it please?
Hello🙂 did you come on issue when video from c64 on composite and svideo was darker than normal? My friend have this issue, we changed Vic and with my it's bright as it should be. Any ideas where we can pull it up? C64c short board.
Another great video!!!!!!!
do you do any long term power on tests? like hours?
Please, never stop making C64 repair videos. No matter how many you make I always like these the best. I WILL NEVER GET TIRED OF C64 REPAIR VIDEOS!
You rock. 😘
There should be c64/mac/yada repairs every once or twice a month. Just for us and for you to not forget what to do and what has to be done.
Where do you sell the boards that you fix?
Nice run-through as always, thanks for sharing. And indeed, it should be against the law not to have the 8-bit Dance Party tune played in all of your C64 vids! ;)
Does the test cart test the tape port properly, as if I had loaded a game from tape? Or just some simple sigles. Thanks John (uk)
I'll try to save Adrian having to look this up as I recently had to figure this one out myself. It's just looking for signalling with two loopbacks. It sends a signal on one pin and looks for it to come back on another and does that with two pairs of pins.