Great job. You're beginning to do what I've said elsewhere I'm so surprised I've never seen before considering the HUGE number of C64 repair videos and forums - provide scope traces at key points from a working C64.
@@MuzafferB74 MindFlareRetro has already made one. You can find it on his site along with links to Sven Petersen's oscilloscope guide mindflareretro.com/resources
It freaking works. Love it! I received a 64C a month ago and had a very hot ram chip. Took forever for replacement chip and sockets to come, but luckily it was all it was. My daughter heard me scream... it ×××× works from upstairs. It's great. Lol. Also hot air if you have a stubborn stuck chip with a little gently prying works amazing. Again great video
Thank you for the photos at the end of this video 🙂. I’ve just bought my first ever oscilloscope, it’s a crt one. This will be a great help in learning how to use it 👍
I just wanted to say that your videos helped me greatly to fix my commodore 64 I bought accidentally on ebay :) That was my first attempt bidding and I confused two tabs in my browser and put a bid on a not-working commodore and I won it, of course as I was the only idiot. Deal is deal so I got it back in August, it surely didn't work (black screen), but looked fine. The seller mentioned that the video cable melted so I assumed he shorted it somehow. So I started watching your videos, learning how to solder, learning electronics etc. Had to buy an oscilloscope, multi-meter, soldering station, desoldering station etc. After this troubleshooting videos I did couple days of probing and figured that PLA is probably bad, so I double checked other ICs and ordered PLA from ebay. Desoldered the old one (thanks for your advises on adding solder before desoldering) and soldered in a socket and put new PLA into it and it worked! My first computer I ever fixed. Of course, the investments I made are way above what would normal person spend on the old not-working commodore :) (I won't even mention how much did I spend on all that equipment). Now I got 1541 to fix... and probably gonna buy an old soviet PDP-11 clone from Slovakia (I had one when I was a kid) but I'm hesitating because to fix it I will have to order some ICs and other parts from russia which is almost impossible these days (considering that madness they got themselves into). BTW I've never had any of the real western 8bit-era computers like commodore, or amiga, or even spectrum before. So learning right now about what you guys played with while I was on the other side of the iron curtain :)
Fantastic and congratulations on your first repair! The tools will pay themselves off in the long run I'm sure. It's so great to hear when another person is able to repair something after watching some UA-cam videos. Obviously you have the drive and competence to be able to do it, and I hope it gives you new found passion to go on and repair more busted tech and keep it out of landfill. All the best with your repair journey, I hope you can get your hands on some systems you grew up with and get them going
You can, but not the standard dip sockets that most folks would have on hand. The super PLA has a 1.778mm pin pitch as opposed to the more common 2.54mm
Yes there is a socket 64 pin, done once on one C64 short board. Mine had black screen, but when cart was inserted computer worked and passed all diagnostic. At the end desoldered all chips from board, ordeded new SuperPLA but i was same issue, black screen without cartrigde, tested all chips on other board, create new BASIC+KERNAL chip, nothing. So long story shot, there was short on cart port when no cart is inserted :D, replaced cartridge port and it was working :)
Good video. FWIW I have had to replace the 64 pin PLA on more than a few 64C E boards that have been through my shop. They fail almost as often as the PLAs in the breadbins and I suspect as time moves on their failure rate will increase. The 1.77mm sockets are readily available, I stock them, have at least 20 on hand as are the 64 pin PLAs.
Good video. I don’t think there can be too many examples of what a normal scope output should be. Be nice if there was a database of pin images during normal operation. As these machines age we’re going to have to troubleshoot more and more.
GREAT video. Damn, that must have taken you a while to put together. Do you happen to have individual still images or "slides" of your measurement shots from the end of this video? I would like to make a PDF for myself, and others if that's okay. Or I can just grab screen captures from here, actually.
It is the TL866ii, and the software that comes bundled with it. You can find more info on it here: ua-cam.com/video/SQ0MVKTrAD4/v-deo.html BTW I believe the XGECU TL866ii is being replaced by a new version called the T48 and T56
Hi, I noticed that you have an alike soldered pen like mine. What is a good temperature to solder at? I always have a ugly looking solder job. U mentioned it was because not enough heat. I'm nervous lol
So pin 40 should have 5V on it, and pin 39 should have the ~1Mhz clock. Double check those again, and also check to see if the 1Mhz clock into the CPU is there on pin 1. Let me know what you see on those 3 pins
The program is the standard one for the TL866 programmer, I believe the program itself is called XGECU. Yes board is powered on when probing, otherwise there would be nothing on the scope
All of these videos have great information! One thing I don't recall seeing, and I might have missed it, on the 250407 boards next to the Vic chip there is a jumper for PAL. Does this tie into the RF modulator or the video out to make the video signal PAL versus NTSC? I noticed that there is another spot right next to the PAL jumper. Is that for something else?
Not quite, the PAL and NTSC machines use a different VIC-II and click frequency. Although I've never tried it, I believe you need to swap out the crystal, VIC-II, and short/open that jumper. The 2nd jumper may be for PAL I/G but to be honest I'm not sure
@@TheRetroChannel Thank you for the information. Well, there is only one way to find out. The thing that has always irritated me the most is the region formats. Thankfully PCs are mostly immune to that today but things like gaming systems, TVs and Blu-Ray players aren't unless you have a region free system.
It's the Xgecu TL-866ii programmer. These are discontinued and have been replaced by the Xgecu T48. The software for the programmer includes some basic logic tests which is what I used here
@@TheRetroChannel Thanks for the quick reply. I'm not sure I need one yet, but it's certainly not going to break the bank if I ever should do. I'm currently trying to solve a C64 black screen problem, so I may need one eventually.
Great video series! May I ask, where did you buy that IC extractor tool? I have seen it in videos from many people and have been searching for it for a while now. Can only find cheap simple ones that aren't as fancy.
Got it from aliexpress, there's a link to it in the video description. The arms/claws are a bit flimsy and can bend out of shape, but it was about 1/8th the price of the Jonard one
My PLA I4 pin 5 is around 2 volts and flashing rapidly on the oscilloscope. If this goes bad, could this also make the ROM chips go bad, because kernal and basic are pretty hot.
Seems unlikely that it would affect the ROMs. PLA I4 (also called VA14 on the schematics) connects to U14 and U2. I would suspect the PLA, followed by the 74LS258 at U14 (especially if it's a MOS branded chip), then the CIA at U2. BUT, it could be completely unrelated to any of those things, so take all this with a grain of salt. Good luck
@@TheRetroChannel thanks for the reply. They say the PLAs usually go bad, so I've bought a modern day replacement, I'll go from there. If the ROMs are hotter than the VIC after a few minutes on, do you think they would be suspect? The screen when powered up is just blank, not how they show ROM problems with random characters and such. I removed the SID and CIAs for testing with no changes. I know the VIC is fine, it worked in my friends machine.
@@computeraidedworld1148 🤔 I've had some hot ROMs that still worked just fine. I've also had ones that ran cool. But in all cases the VIC always gets hotter than everything else
@@TheRetroChannel alrighty, well I'll wait for that PLA, if that doesn't work I'm going to look at these ROMs, it's way hotter than the VIC. Thanks for your insight, and I'm glad I found this channel, well made videos.
Yep, wait for the PLA and see if that makes any difference. If not, you can remove the BASIC ROM and the machine should boot to a blue screen with no text. But you cannot boot without a KERNAL, you'll just get a black screen
Awesome stuff, Keep it up. any chance you'd put the pictures up on a website? it would be the next step and a great source of fault finding to anyone who hasn't got a 2nd 64 to scope a sus signal.
Quick note: The oscilloscope signals at the end were taken with the C64 booted into BASIC, without any peripherals or cartridges connected
Great job. You're beginning to do what I've said elsewhere I'm so surprised I've never seen before considering the HUGE number of C64 repair videos and forums - provide scope traces at key points from a working C64.
Hi, do you mind if I make a PDF file from those signal screenshots and refer you as the source and also give a link to this video please?
@@MuzafferB74 MindFlareRetro has already made one. You can find it on his site along with links to Sven Petersen's oscilloscope guide mindflareretro.com/resources
It freaking works. Love it! I received a 64C a month ago and had a very hot ram chip. Took forever for replacement chip and sockets to come, but luckily it was all it was. My daughter heard me scream... it ×××× works from upstairs. It's great. Lol. Also hot air if you have a stubborn stuck chip with a little gently prying works amazing. Again great video
Thank you for the photos at the end of this video 🙂. I’ve just bought my first ever oscilloscope, it’s a crt one. This will be a great help in learning how to use it 👍
Thank you for the images at the end of the video! This helps me tracking down the problem I have with a C64.
I just wanted to say that your videos helped me greatly to fix my commodore 64 I bought accidentally on ebay :) That was my first attempt bidding and I confused two tabs in my browser and put a bid on a not-working commodore and I won it, of course as I was the only idiot. Deal is deal so I got it back in August, it surely didn't work (black screen), but looked fine. The seller mentioned that the video cable melted so I assumed he shorted it somehow. So I started watching your videos, learning how to solder, learning electronics etc. Had to buy an oscilloscope, multi-meter, soldering station, desoldering station etc. After this troubleshooting videos I did couple days of probing and figured that PLA is probably bad, so I double checked other ICs and ordered PLA from ebay. Desoldered the old one (thanks for your advises on adding solder before desoldering) and soldered in a socket and put new PLA into it and it worked! My first computer I ever fixed. Of course, the investments I made are way above what would normal person spend on the old not-working commodore :) (I won't even mention how much did I spend on all that equipment). Now I got 1541 to fix... and probably gonna buy an old soviet PDP-11 clone from Slovakia (I had one when I was a kid) but I'm hesitating because to fix it I will have to order some ICs and other parts from russia which is almost impossible these days (considering that madness they got themselves into). BTW I've never had any of the real western 8bit-era computers like commodore, or amiga, or even spectrum before. So learning right now about what you guys played with while I was on the other side of the iron curtain :)
Fantastic and congratulations on your first repair! The tools will pay themselves off in the long run I'm sure. It's so great to hear when another person is able to repair something after watching some UA-cam videos. Obviously you have the drive and competence to be able to do it, and I hope it gives you new found passion to go on and repair more busted tech and keep it out of landfill. All the best with your repair journey, I hope you can get your hands on some systems you grew up with and get them going
@@TheRetroChannel Thank you ! Appreciate it. Currently watching all those 1541 troubleshooting of yours ...
Oof, good luck with that. Those videos are probably pretty old and hard to follow. But if you get stuck, feel free to ask for help
Great video. Someone may have commented already, but if not, you can use two short sockets instead of one very long socket for the super PLA
You can, but not the standard dip sockets that most folks would have on hand. The super PLA has a 1.778mm pin pitch as opposed to the more common 2.54mm
"Will you look at that! It's working! It's freaking working!" - Adrian Black
Thank you VERY MUCH! those screenshot are so valuable and helpful.
Yes there is a socket 64 pin, done once on one C64 short board. Mine had black screen, but when cart was inserted computer worked and passed all diagnostic. At the end desoldered all chips from board, ordeded new SuperPLA but i was same issue, black screen without cartrigde, tested all chips on other board, create new BASIC+KERNAL chip, nothing.
So long story shot, there was short on cart port when no cart is inserted :D, replaced cartridge port and it was working :)
Interesting, maybe I should seek out one of those 64pin sockets and make a short board testbed 🤔
Good video. FWIW I have had to replace the 64 pin PLA on more than a few 64C E boards that have been through my shop. They fail almost as often as the PLAs in the breadbins and I suspect as time moves on their failure rate will increase. The 1.77mm sockets are readily available, I stock them, have at least 20 on hand as are the 64 pin PLAs.
Fantastic video, a great reference guide for any future troubleshooting. Love your channel.
finally the video I was looking for, a thousand times thanks for me being a geek
Good video. I don’t think there can be too many examples of what a normal scope output should be. Be nice if there was a database of pin images during normal operation. As these machines age we’re going to have to troubleshoot more and more.
Thank you so much for this video!
Nice! -Mark.
GREAT video. Damn, that must have taken you a while to put together. Do you happen to have individual still images or "slides" of your measurement shots from the end of this video? I would like to make a PDF for myself, and others if that's okay. Or I can just grab screen captures from here, actually.
Yeah I took a while to put together, do you like my MS paint skillz?
I'll email you all the files, feel free to share, use, do whatever with them
Can I learn what is the hardware and software you're using at 9:05 Logic testing please?
It is the TL866ii, and the software that comes bundled with it. You can find more info on it here: ua-cam.com/video/SQ0MVKTrAD4/v-deo.html
BTW I believe the XGECU TL866ii is being replaced by a new version called the T48 and T56
@@TheRetroChannel Many thanks!
Hi, I noticed that you have an alike soldered pen like mine. What is a good temperature to solder at? I always have a ugly looking solder job. U mentioned it was because not enough heat. I'm nervous lol
I have a different one now, but when I was using the older one it was usually set to 350°C
Thanks for the videos. I got black screen Assy 250469. Pin 39 and 40 do not give me any signal on CPU. Any idea?
So pin 40 should have 5V on it, and pin 39 should have the ~1Mhz clock. Double check those again, and also check to see if the 1Mhz clock into the CPU is there on pin 1. Let me know what you see on those 3 pins
Great vid , whats the chip test program? and also is the board powered whilst probing with the scope?
The program is the standard one for the TL866 programmer, I believe the program itself is called XGECU.
Yes board is powered on when probing, otherwise there would be nothing on the scope
All of these videos have great information! One thing I don't recall seeing, and I might have missed it, on the 250407 boards next to the Vic chip there is a jumper for PAL. Does this tie into the RF modulator or the video out to make the video signal PAL versus NTSC? I noticed that there is another spot right next to the PAL jumper. Is that for something else?
Not quite, the PAL and NTSC machines use a different VIC-II and click frequency. Although I've never tried it, I believe you need to swap out the crystal, VIC-II, and short/open that jumper.
The 2nd jumper may be for PAL I/G but to be honest I'm not sure
@@TheRetroChannel Thank you for the information. Well, there is only one way to find out. The thing that has always irritated me the most is the region formats. Thankfully PCs are mostly immune to that today but things like gaming systems, TVs and Blu-Ray players aren't unless you have a region free system.
Hello again, here's another question please :)
What's your heat settings when soldering/adding fresh solder/desoldering please?
For soldering signal traces 330C, power planes 360-380C. Add about 10% to those figures for desoldering.
Testing ICs with the MiniPro is not reliable. I had one defective IC which was shown as good. I replaced it and since then the board works fine!
A great series that has already helped me; but what is the logic tester you use at 9:05 please?
It's the Xgecu TL-866ii programmer. These are discontinued and have been replaced by the Xgecu T48. The software for the programmer includes some basic logic tests which is what I used here
@@TheRetroChannel Thanks for the quick reply. I'm not sure I need one yet, but it's certainly not going to break the bank if I ever should do. I'm currently trying to solve a C64 black screen problem, so I may need one eventually.
Great video series! May I ask, where did you buy that IC extractor tool? I have seen it in videos from many people and have been searching for it for a while now. Can only find cheap simple ones that aren't as fancy.
Got it from aliexpress, there's a link to it in the video description. The arms/claws are a bit flimsy and can bend out of shape, but it was about 1/8th the price of the Jonard one
@@TheRetroChannel Thanks! Feel a bit embarrassed now that I didn't see the link in the video description. 🙂
I had the exact same issue on my C64c. I have a sneaking suspicion someone tried using a Megadrive pad with it.
Yeah, I guess that's a possibility. Wonder if Sega knew that would be an issue, forced upgrade for gamers
My PLA I4 pin 5 is around 2 volts and flashing rapidly on the oscilloscope. If this goes bad, could this also make the ROM chips go bad, because kernal and basic are pretty hot.
Seems unlikely that it would affect the ROMs. PLA I4 (also called VA14 on the schematics) connects to U14 and U2. I would suspect the PLA, followed by the 74LS258 at U14 (especially if it's a MOS branded chip), then the CIA at U2. BUT, it could be completely unrelated to any of those things, so take all this with a grain of salt. Good luck
@@TheRetroChannel thanks for the reply. They say the PLAs usually go bad, so I've bought a modern day replacement, I'll go from there. If the ROMs are hotter than the VIC after a few minutes on, do you think they would be suspect? The screen when powered up is just blank, not how they show ROM problems with random characters and such. I removed the SID and CIAs for testing with no changes. I know the VIC is fine, it worked in my friends machine.
@@computeraidedworld1148 🤔 I've had some hot ROMs that still worked just fine. I've also had ones that ran cool. But in all cases the VIC always gets hotter than everything else
@@TheRetroChannel alrighty, well I'll wait for that PLA, if that doesn't work I'm going to look at these ROMs, it's way hotter than the VIC. Thanks for your insight, and I'm glad I found this channel, well made videos.
Yep, wait for the PLA and see if that makes any difference. If not, you can remove the BASIC ROM and the machine should boot to a blue screen with no text. But you cannot boot without a KERNAL, you'll just get a black screen
Awesome stuff, Keep it up. any chance you'd put the pictures up on a website? it would be the next step and a great source of fault finding to anyone who hasn't got a 2nd 64 to scope a sus signal.
There's a link in the video description to Sven Petersen's website. He has a bunch of scope images and explainations of each one