I've never seen a ceramic CPU. I didn't even know they existed until seeing this video. At first, I thought it was a VIC-II in U7. And hopefully there will be more C64 repair-a-thons!
I've only ever seen pictures of ceramic 6510's, so it was a surprise to me, too. There may be more C64 repairathons if I can get enough non-working machines. They're becoming harder to come by. I assume that has something to do with how many of us are already out there repairing them. Watch around mid-2025 to see if I've managed to collect some. :) Thanks for watching!
You're very welcome. I don't know about future C64 repairathons (broken C64s are getting harder to come by and more expensive), but there's definitely a lot more content to come. Thanks for the watch and we'll see you in the next one!
The reset fix is a must do for the 326298 boards so I'm glad to see that done. I totally forgot about those ceramic filter caps on the SID but it turns out mine has the right values. Maybe Commodore started putting in the right values or somebody changed them afterwards. As for the 5V regulator, I'd certainly recommend a bigger heatsink like the cartridge port shield. Don't risk that thing cooking and failing short circuit. The svideo mod is optional but I'm a sucker for better video output.
Thanks, Mark. I'll get around to the regulator mod. I just didn't feel like drilling right then. It was late at night. Your s-video mod is easy enough and I may do it, I just don't have a cable built that would work with it. That's what held me back there. I really hate building cables :)
Surprisingly, broken ones are getting less and less common and more and more expensive. I think there may be too many of us out there fixing them. But you're right about the reasons. Thanks for watching!
Great Thank You ,Enjoyed watching.I'm in Country Drouin Vic Australia and worked on at least 20 of these and learning all the time. actually there is some models with the SID and PLA the other way round. I Nearly got cort with that one. Thank's.
There are four different major revisions of the C64 long board. The KU-14194HB and the 326298 have the SID and PLA side-by-side. In the 250407, the PLA is next to the 6510 and the SID is in front of it next to the VIC-II RF shield. Finally, the 250425 has the SID next to the 6510 and the PLA next to the VIC-II shield. All you really need to remember is that the PLA is ALWAYS U17. And yes, this has caught me on at least one occasion when I put them in the wrong sockets and ended up blowing out a PLA with 12VDC. Kicked myself for quite a while about that.
Another rushed comment without waiting the end of the video; ARMSID does not use the filter caps, those are only for an original SID, and I believe those pF caps are correct for a 6581 SID, nF caps are used by the later 8580. And an idea, maybe you would like to install those ceramic VIC-II and 6502 from the board #10 on this board, where they would look more period correct.
Thanks, Bora! I'll probably be swapping an original 6581 SID into the board eventually (along with the ceramic 6567R56A and the ceramic 6510 from machine 10 and a few other more period-accurate chips) at a future date, so the cap replacement will absolutely help there. I used the ArmSID to get the machine up and running.
Even check the power brick. Sometimes they go bad and put out 35 volts or so. With the voltage issues, I'd have changed the capacitors. Sometimes that pulls things down too. There could be a lack of capacity or excessive ESR. On the 120 ohm resistor, 75-100 may work better there. And yeah, on the reset, cut pin 9 on the 556 and add the resistor. Keep the bodge wire in place.
I never use the original power bricks. When working on a C64 or VIC-20, I use a custom built power supply with overcurrent and overvoltage protection. As for the original brick, if I get one with a C64 I buy, I just gut it and use the case and cables to build a safe one into. The potted components just go in the bin. The electrolytics on C64s are *almost* never the problem. They weren't made during the capacitor plague, though that's no guarantee. 120Ω is the value recommended by most folks who do these repairs and matches the schematics, but yes, 75 or 100Ω might give a little brighter picture on composite, though it would leave the luma signal a little out of spec for an s-video output if I wanted to do that mod, too. There are other ways to make the reset mod that I've seen, but this seems the most straight-forward and easiest to reverse if you ever want to put the board back to stock configuration.
@@YARC-1981 -- On another channel, the tech measured and found that even 120 ohm gave voltages on the low side of the specs and determined 75-100 ohm for the specific machine met the specs better. But then, I think it used the oldest VIC-II. I've seen other types of machines where aging filter capacitors on the power rail contributed to lower voltages at the other end of the board. That was the case on an arcade game. The machine was running a little on the unreliable side and changing the large filter caps helped. Of course, they don't change every electrolytic capacitor. For instance, on the solenoid driver board, they usually leave the one in the HV circuit for the plasma alone. It usually doesn't need replacing, and sometimes the machine is upgraded to not even use that rail. In that case, the 5V rail should likely be beefed up a little to accommodate slightly more load there (since an LED display kit was installed) What many don't realize is that if electrolytics test fine on a "capacitor tester," they can still be marginal. In fact, failing ones may test even "better" than a new one. To test this, you can put a resistor across even a new capacitor and use a capacitance meter. It may read "too high" when the resistor ensures it isn't working as good as it could. Those meters rely on a math formula and apply it to the rate of charge. That is like measuring how long it takes to fill a bucket with a hole in the bottom with water and concluding the 5-gallon bucket is a 7-gallon bucket because it fills at the rate of one. I agree that these were before the capacitor plague. It also depends on who made them. For instance, you can likely take a modern Chinese-made PC PSU, change all the capacitors (even brand new), and make it more reliable. In that case, maybe change the fan motor too (or at least disassemble and lubricate it). Some modern switching PSUs use diodes in interesting ways where they are more critical such as using them in series. I guess that is to interface between the rare few ICs that use higher voltages to drive 3.3 - 5V ICs (since the forward drop is much higher). So they might not test as shorted out but still might not be working. And I've seen regular diodes used as low-voltage Zeners too such as wiring two of them in reverse piggyback configuration to simulate a low-voltage MOV in an audio circuit as a crude gain control. (Then it won't go past 0.6V in either direction.) Then with other things made in budget conditions or even sweatshops, the issue is not so much the quality of the components, but more the care in which it was assembled. You may, for instance, be able to take a mechanical wristwatch purchased from Alibaba or similar, disassemble it completely, do a full servicing, clean and inspect everything, burnish any rough edges on the pivots, lubricate it (using common sense and other companys' service guides if you can't find any for that one), and adjust it for better performance and longevity. They may use the same process to make the parts as more reliable companies, but they might not even lubricate or adjust them properly. Sometimes with such watches, you can also make upgrades if you have the tools and know-how. An example would be replacing any metal bushings with jewel bushings.
@@PlumGurly With regard to the 120Ω resistor, I believe you're referring to Adrian's Digital Basement. I've seen that video and yes, he determines that a lower value resistor gives him a better result on composite video. He never tried to get s-video out. What specific capacitors on the board are you concerned about? If you're referring to the large electrolytics used in the regulation circuit, those are only relevant to the +5V and +12V isolated power going to the VIC-II and the SID. They don't have anything to do with the 5V rail going to all the other components. That rail is supplied by the external power brick, so changing those out would do nothing for the voltage at the other end of the board even if they were faulty or marginal.
@@YARC-1981 -- In the context, you can tell I was speaking about the power capacitors. You mentioned the voltage being low by the ports. I was just explaining how that could be the case. You said it wasn't and had moved on. I just described how that can be the case with other types of machines.
I've known about the SixtyClone for quite a while, but I'm more tempted to build up one of bwack's replicas, probably the 250407. Keep watching around the end of the year to see what I end up with. Thanks!
I've never seen a ceramic CPU. I didn't even know they existed until seeing this video. At first, I thought it was a VIC-II in U7. And hopefully there will be more C64 repair-a-thons!
Plastic packages came later, during 70's and very early 80's, almost all ICs (RAM, Logic, etc) were in ceramic packages.
I've only ever seen pictures of ceramic 6510's, so it was a surprise to me, too. There may be more C64 repairathons if I can get enough non-working machines. They're becoming harder to come by. I assume that has something to do with how many of us are already out there repairing them. Watch around mid-2025 to see if I've managed to collect some. :) Thanks for watching!
Which is why it surprised me that this one had an '86 date on it.
Me either... I thought it was a ceramic vicII myself
what a pity it ended. I hope still that there is more in the future, Thx Todd
You're very welcome. I don't know about future C64 repairathons (broken C64s are getting harder to come by and more expensive), but there's definitely a lot more content to come. Thanks for the watch and we'll see you in the next one!
The reset fix is a must do for the 326298 boards so I'm glad to see that done. I totally forgot about those ceramic filter caps on the SID but it turns out mine has the right values. Maybe Commodore started putting in the right values or somebody changed them afterwards.
As for the 5V regulator, I'd certainly recommend a bigger heatsink like the cartridge port shield. Don't risk that thing cooking and failing short circuit. The svideo mod is optional but I'm a sucker for better video output.
Thanks, Mark. I'll get around to the regulator mod. I just didn't feel like drilling right then. It was late at night. Your s-video mod is easy enough and I may do it, I just don't have a cable built that would work with it. That's what held me back there. I really hate building cables :)
@@YARC-1981 100%. Building cables is my least favourite thing
Great to see the old commodores still up and running..Great job.
Great video and work as always:) I learned a few tricks with the older revision. Thanks. Until next time.. (the 250466 board) take care
Much appreciated, Donald! See you in the next one.
Excellent work and series! Thanks for sharing all the good knowledge
I can't imagine I had much to offer you, Rudy. You already seem better informed than I am. But high praise. Thanks!
@YARC-1981 We know, learn, and share. That's part of the fun of retro computers. Thanks for a great channel!
Thanks for the series! I really enjoyed.
My pleasure!
There will always be more broken C64s because:
1. They made so many of them
2. Commodore always spent as little as possble on quality.
Surprisingly, broken ones are getting less and less common and more and more expensive. I think there may be too many of us out there fixing them. But you're right about the reasons. Thanks for watching!
Great Thank You ,Enjoyed watching.I'm in Country Drouin Vic Australia and worked on at least 20 of these and learning all the time. actually there is some models with the SID and PLA the other way round. I Nearly got cort with that one. Thank's.
There are four different major revisions of the C64 long board. The KU-14194HB and the 326298 have the SID and PLA side-by-side. In the 250407, the PLA is next to the 6510 and the SID is in front of it next to the VIC-II RF shield. Finally, the 250425 has the SID next to the 6510 and the PLA next to the VIC-II shield. All you really need to remember is that the PLA is ALWAYS U17. And yes, this has caught me on at least one occasion when I put them in the wrong sockets and ended up blowing out a PLA with 12VDC. Kicked myself for quite a while about that.
Awesome series! Great job fixing those C64s and loved the informative videos!
Thank you. I appreciate that.
Another rushed comment without waiting the end of the video; ARMSID does not use the filter caps, those are only for an original SID, and I believe those pF caps are correct for a 6581 SID, nF caps are used by the later 8580. And an idea, maybe you would like to install those ceramic VIC-II and 6502 from the board #10 on this board, where they would look more period correct.
Thanks, Bora! I'll probably be swapping an original 6581 SID into the board eventually (along with the ceramic 6567R56A and the ceramic 6510 from machine 10 and a few other more period-accurate chips) at a future date, so the cap replacement will absolutely help there. I used the ArmSID to get the machine up and running.
Even check the power brick. Sometimes they go bad and put out 35 volts or so.
With the voltage issues, I'd have changed the capacitors. Sometimes that pulls things down too. There could be a lack of capacity or excessive ESR.
On the 120 ohm resistor, 75-100 may work better there.
And yeah, on the reset, cut pin 9 on the 556 and add the resistor. Keep the bodge wire in place.
I never use the original power bricks. When working on a C64 or VIC-20, I use a custom built power supply with overcurrent and overvoltage protection. As for the original brick, if I get one with a C64 I buy, I just gut it and use the case and cables to build a safe one into. The potted components just go in the bin.
The electrolytics on C64s are *almost* never the problem. They weren't made during the capacitor plague, though that's no guarantee.
120Ω is the value recommended by most folks who do these repairs and matches the schematics, but yes, 75 or 100Ω might give a little brighter picture on composite, though it would leave the luma signal a little out of spec for an s-video output if I wanted to do that mod, too.
There are other ways to make the reset mod that I've seen, but this seems the most straight-forward and easiest to reverse if you ever want to put the board back to stock configuration.
@@YARC-1981 -- On another channel, the tech measured and found that even 120 ohm gave voltages on the low side of the specs and determined 75-100 ohm for the specific machine met the specs better. But then, I think it used the oldest VIC-II.
I've seen other types of machines where aging filter capacitors on the power rail contributed to lower voltages at the other end of the board. That was the case on an arcade game. The machine was running a little on the unreliable side and changing the large filter caps helped. Of course, they don't change every electrolytic capacitor. For instance, on the solenoid driver board, they usually leave the one in the HV circuit for the plasma alone. It usually doesn't need replacing, and sometimes the machine is upgraded to not even use that rail. In that case, the 5V rail should likely be beefed up a little to accommodate slightly more load there (since an LED display kit was installed)
What many don't realize is that if electrolytics test fine on a "capacitor tester," they can still be marginal. In fact, failing ones may test even "better" than a new one. To test this, you can put a resistor across even a new capacitor and use a capacitance meter. It may read "too high" when the resistor ensures it isn't working as good as it could. Those meters rely on a math formula and apply it to the rate of charge. That is like measuring how long it takes to fill a bucket with a hole in the bottom with water and concluding the 5-gallon bucket is a 7-gallon bucket because it fills at the rate of one.
I agree that these were before the capacitor plague. It also depends on who made them. For instance, you can likely take a modern Chinese-made PC PSU, change all the capacitors (even brand new), and make it more reliable. In that case, maybe change the fan motor too (or at least disassemble and lubricate it). Some modern switching PSUs use diodes in interesting ways where they are more critical such as using them in series. I guess that is to interface between the rare few ICs that use higher voltages to drive 3.3 - 5V ICs (since the forward drop is much higher). So they might not test as shorted out but still might not be working. And I've seen regular diodes used as low-voltage Zeners too such as wiring two of them in reverse piggyback configuration to simulate a low-voltage MOV in an audio circuit as a crude gain control. (Then it won't go past 0.6V in either direction.)
Then with other things made in budget conditions or even sweatshops, the issue is not so much the quality of the components, but more the care in which it was assembled. You may, for instance, be able to take a mechanical wristwatch purchased from Alibaba or similar, disassemble it completely, do a full servicing, clean and inspect everything, burnish any rough edges on the pivots, lubricate it (using common sense and other companys' service guides if you can't find any for that one), and adjust it for better performance and longevity. They may use the same process to make the parts as more reliable companies, but they might not even lubricate or adjust them properly. Sometimes with such watches, you can also make upgrades if you have the tools and know-how. An example would be replacing any metal bushings with jewel bushings.
@@PlumGurly With regard to the 120Ω resistor, I believe you're referring to Adrian's Digital Basement. I've seen that video and yes, he determines that a lower value resistor gives him a better result on composite video. He never tried to get s-video out.
What specific capacitors on the board are you concerned about? If you're referring to the large electrolytics used in the regulation circuit, those are only relevant to the +5V and +12V isolated power going to the VIC-II and the SID. They don't have anything to do with the 5V rail going to all the other components. That rail is supplied by the external power brick, so changing those out would do nothing for the voltage at the other end of the board even if they were faulty or marginal.
@@YARC-1981 -- In the context, you can tell I was speaking about the power capacitors. You mentioned the voltage being low by the ports. I was just explaining how that could be the case. You said it wasn't and had moved on. I just described how that can be the case with other types of machines.
Now do the SixtyClone PCB build from Bob’s Bits.
I've known about the SixtyClone for quite a while, but I'm more tempted to build up one of bwack's replicas, probably the 250407. Keep watching around the end of the year to see what I end up with. Thanks!