Fixing the C16 and getting disk I/O working
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- เผยแพร่เมื่อ 3 ต.ค. 2024
- Part 2: Fixing my broken Commodore 16 and then fixing the inoperative disk drive (IEC port) due to using a MOS 6510. Kernal mod time!
Part 1: • Commodore 16/Plus4 CPU...
Part 3: Coming soon! PAL/NTSC switching and 64k RAM upgrade.
Andy's Blog (Hackjunk) where I initially got this idea:
hackjunk.com/20...
MOS 8510 to MOS 6510 Adapter Chart/Pinout/Information:
pastebin.com/j...
Modified Kernels:
drive.google.c...
TL866A EPROM Programmer I use:
www.ebay.com/i...
DSLogic Basic Logic Analyzer I use:
www.ebay.com/i...
Really like that you left in a mistake/oops. It's perfectly reasonable to find yourself heading down an unproductive path, making mistakes, or wanting to use a fancy edge-case tool when a simple method would work better. We're all tempted to portray a perfect level of competency, but that's not a true representation of what it means to be human and it hinders the learning process.
In my opinion as complete novice, I find it important to see what errors/mistakes could occur and how to avoid or fix these. BTW great video! Thank you!!!
I give you full credit for attempting to troubleshoot it, rather than just shotgunning and replacing parts -- this is a difference between the roles of an engineer and a technician. Keep up the great videos! Best wishes.
One of your very best and richest videos in my own humble opinion. It covers many different aspects of hardware troubleshooting, using amazing tools (last time I touched an oscilloscope was in the mid 80s... gosh have they changed a lot!), and a bit of software hacking. Love this. And I was especially proud to have spotted the 'oops' when watching the logic analyzer and you started saying 'this is not normal'. Well, at least 74LS logic hasn't changed much since the 80s so I can could catch this before you said 'er... still low' :-)
8:47 That 'oh, it's still a low' followed by the fade to black is deadpan comedy gold! Thanks for leaving it in :)
This is a great example of how troubleshooting really goes in real life. Following the logic flow, getting lost in your own mistakes, trying again and then finding something unexpected followed by a victory lap. The most difficult ones are the most rewarding.
One of the things I enjoy about this channel is the honesty in leaving in the unintentional learning opportunities (aka 'mistakes'). We all encounter them, and no one enjoys it. However, they are valuable! Thanks Adrian!
I'm glad you left in the errors. We can learn from them, as well as you.
I have found that unless you have a custom\exotic and/or a bed-of-nails tester, then *in-circuit diagnosis* requires experience (either earned, or given) to limit you to specific areas. In my experience, loosing 1 hour is nothing.
Note that each time you remove or replace a component introduces a risk that you need to cover. If the 'value' is there (either for experience's sake, or actual), then in-circuit diagnosis can be rewarding.
2:11 - "overcloking": when the Klingons find out you're on to them so they divert more power to the cloaking device
Analysing these Logic ICs and Schematics is not that trivial - but you learn a lot by doing it, even though it didn´t give you a clue in the end. I would have really needed a break after that ;)
Good work. Got a kick out of seeing my SD2IEC device in the video :)
Very nice work. Appreciate you showing the trial and errors as well. This hobby can be a constant learning curve. Fantastic result
It was painful seeing you go down a rabbit hole but you got back up and fixed it. Inspirational!
I appreciate your attempt to fault find. Most videos on youtube are basically someone swapping things out or tearing bits and pieces from another machine to make one good machine. As this technology gets older and more valuable we need to be more knowledgable to keep it all working.
When troubleshooting a board, it is far too easy to find yourself led down a bunny trail. Thanks for showing that!
Brilliant video. Really enjoying to watch. Have a C16 arriving in the post soon to play with, so the timing of these videos is perfect.
Next time please show some more of the debugging, it is very interesting even though it didn't fix the problem :-)
Maybe a guide on how to use the logic-analyser to could be awesome :)
These videos makes me want to learn to solder and use a multimeter and whatnots to then fix all my old omputers!
Very useful and interesting. Now I have to fix my C16 and extend the RAM. Thank you for this valuable information.
Very interesting. Didn't know you could test chips with the programmer. Going to have to buy one
The commodore 16 is the real 8 bit king.
I had the same issue with the TRS80 MC10. The motherboard chip count was low and the majority of the chips was TTL. I just pulled them all and put in sockets and used it as my MC10 test board for all the other MC10's stacked for repair
I know that feeling, I repaired 3 cpc machines in the past days and it's awesome.
@Adrian Black
This work is fascinating! Really enjoying it and looking forward to part 3!
This almost feels like a Louis Rossmann video. But no fanspin :(
Or whining about Apple :-D
But we got fan spin later on!
or JTAG
Who would've thought the PAL and NTSC versions actually have differing KERNALs. Nice work "transplanting" the 6510 handling changes to the NTSC variant!
Here's hoping the guys at the MockA65xx finalize their product soon - that's supposed to be a drop-in replacement for all 65xx series CPUs, including the C16's 7501/8501 and even the C128's 8502!
Its prob why you can't play NTSC/PAL games in different countries too.
There is also the internal „clock“ a jiffy counter that is different for pal vs. ntsc 50/60 Hz that have to be programmed different if I remember correctly to get similar timings for I/o and stuff.
The internal struggle of wanting to start with using a schematic to troubleshoot vs. just chip swapping and instincts is very frustrating. I find I only ever want to try to repair something by schematic when I'm shooting a video because it looks better on camera. But really with this kind of old stuff a lot of times it's overkill if it's all simple parts like this.
I also completely understand wanting to use the schematic because it feels more validating to find the problem by looking for the symptom instead of the cause. Chip swapping feels lazy but it can save so much more time it it's an option and especially if it works. It can also backfire and make you look inexperienced though, like with my attempts at repairing my 1541 drive. It's probably time to bring a schematic into that one.
Nice logic analyzer, which one is it? I went with a bitscope a few years ago (I've never had a reason to show it on camera but I'm probably going to use it in a video in the near-ish future) for it's linux compatibility and python interface software. But the provided applications for it always felt really half baked to me. It seems like all these little USB analyzers have some oversimplified web based software and I really don't like those.
I did not know the minipro could do logic testing! That is going to be very helpful in the future.
$120 DSLogic
Troubleshooting vs randomly swapping parts is all about experience and knowledge. There is a huge steep hill to climb before one is able to beat replacing modules like a monkey - hence most western car shops no longer hire mechanics, swapping parts is cheaper, client pays for spares anyway.
What Adrian should do now is put broken part back and repeat scope/logic debugging just around that part to learn the symptoms and tools.
@@adriansdigitalbasement $65 is a great deal. My $300 BS10 is only 8 channel but does 100MHz analog and has a simple sig-gen built in. I didn't have any scopes when I bought it and a pocket sized scope seemed appealing at the time. Now I would probably go for that option at $65. It looks like SIGROK supports my BS10, I don't know if it can do the analog as well but I'm definitely going to give it a shot.
Having a starting point to work back from really helps for sure. All out dead is the worst if it's not a PSU problem. Getting that C16 running perfectly from nothing by any method is a win in my book!
I know Im kinda off topic but do anybody know of a good site to watch newly released tv shows online?
Excellent video. Actually made me want to go out and get a C16 to experiment with.
New subscriber here. Really enjoyed these two videos. Don't fret about the time spent investigating dead ends; hindsight is 20/20 after all. And hey, if the fault had been where you were testing, checking the 74 series logic would have been the dead end.
I subscribed to your channel quite I while ago, I can't remember, for some giveaway or something, and I watched a couple of videos of yours. Unfortunately, these didn't really float my boat (I can't remember for the life of me which they were), and I forgot about your channel for a while. But upon seeing that last video about the 6510 mod, I've gone back and have been really enjoying your content. It was so unlucky for me to pick some of those less appealing videos to watch because most of your stuff is brilliant!
I can't wait for the next one.
:D
Nice job getting it fixed. I still have a sick board to fix myself :)
Actually I enjoyed leaving that part in. I would encourage you to continue the lesson about NOR gates etc. loved it :)
Last year I made a Crazy Kong Arcade machine and during the build of the cabinet the game PCB developed some graphics problems and missing sprites. It took me 3 months (a few hours now and then) of logic probes, digital scopes, logic analysers, pulling chips and testing in one of those cheap logic testers until I found the faulty chip. It was the first time trying something like this so by the time I had brought some of that test equipment I could have brought another PCB, but I was determined to keep going and when I eventually found the problem the satisfaction was well worth the cost. This year I have 3 x Tetris bootlegs with garbage on screen and 1 Choplifter PCB with missing sprites that I will be trying to repair, but I am not sure how to test PALS and looks like I will need to by the mini pro as the GQ-4X programmer I have does not support them, but it was essential for programming the very old chips that needed 25v. The tetris bootleg run on 6502 cpu !
@@adriansdigitalbasement So lucky for me and thanks to MAME I have the pal code for all 6 on the Tetris PCB. I thought these are one time programmable and I believe the TL866II PLUS does support them or is that the GAL ?
thoroughly enjoying your videos, great work!
I appreciate the tutorials hopefully I could get my commodore Plus 4 to work . Thanks.
Awesome video as always
I have to thank you for you video, as I was able to get both my C16 and Plus/4 running again as a direct result of it. In both cases it turned out to be bad logic chips and or memory. Fortunately my TED, PLA and CPU were all ok. Too bad I didn't know that before I spent money on replacements! D'oh!
Thanks. Never realized the Minipro trick!
YAY! I've been waiting for a mod'ed kernal for awhile! I'v got 4 dead Plus/4s waiting!
Oh , well . You got there in the end .
Just fixed my own C16 a month ago and converted it with eprom/xtal to PAL. (More games are in pal) -- Researching the use of those memory cards that plug into the expansion port seem to indicated that they are problematic unless you completely disable the onboard ram. Looking forward to seeing the detailed upgrade of memory!
Ok wow... I had NO IDEA that the MiniPro eprom programmers can be used to test logic chips!! I must have looked at the software a hundred times and totally did not notice the "Logic IC" setting.
I've been trying to troubleshoot a DIY single board computer kit I'm trying to assemble, and like you I went down the rabbit hole of pouring over the schematics, fiddling with oscilloscopes and logic analyzers, etc. etc. but so far have not found the problem. Maybe I ought to pull out my MiniPro and start testing the logic chips (this SBC uses lots of discrete logic)
well done dude!
Grate video. Troubleshooting will take you down many pates. Grate Job.
Well done!
Thank you Adrian, some great information here.😄👍🏻
Brilliant. Hopefully mine has a similar cause. Time to do some socketing.
Robin from 8 bit show & tell might be able to help you with 6510 assembler. He's a guru at it :)
Great work. Your videos are just great.
I'm having a similar problem with my C16, but no spare parts to test the TED or CPU. 7400 series chips are cheap enough that I just might socket and replace all as you did. Interesting - my board has different MOS-branded 7700 chips than yours above the RAM, but they are likely compatible.
There you have it, Easter egging is way faster than trying to find the root cause of the issue.
NOR = "not or" ---> !(0 | 0)=1/true; !(0 | 1)=0/false; !(1 | 0)=0/false; !(1 | 1)=0/false;
I just found your channel beacouse of YT recommendation. Most likely becasoue of latest thec64 release. :D So great to see it hit the market...
Logic IC's can be such a pain. I've seen them fail in really odd ways, and sometimes they test good in a tester but don't function in-circuit. Especially on old arcade boards that have decades of 24/7 use, tons of oxidization, dirt, and corrosion.
12:39 Exactly my experience in fixing C64's. Just swaping all the Logic chips is cheaper and faster than trying to look around the board for faults.
Nice job, Adrian! :D
I am also guilty of taking the longer paths when troubleshooting when I could have found the problem much faster and easier. It's easy to get carried away.
This video is great stuff.
BTW I found a great explanation of how the 64 ram upgrade works here
myoldcomputer.nl/other-computers/commodore-16/commodore-16-memory-expansion/
Basically the 4464 and 4416 chips have the same pinout. All you need to do is to link A14 and A15 to U7 and U8 the 74LS257 multiplexor chips that drive the multiplexed row and column address lines on the DRAMs.
Yer a wizard Adrian.
Enjoyed this alot ! Thanks !
the 139 is basically an address bus demultiplexer/decoder. it takes the 4 possibilities on 2 input lines and turns it into 4 seperate lines. aka chipselects. :P that pretty much is it's primary use. :P no idea why they put that in if there is also a pla but whatever.
pretty sure Jim Brain the current (pretty sure) owner of JDOS is capable of writing a JDOS kerrnal for this mod if there was enough interest
watching these videos is dangerous for my wallet =) I want an eprom programmer and a c16 now ;)
awesome videos, can't wait the for the next part.
Howdy! Love your stuff!
Great video! I just modded a Plus/4 that was sitting here looking sad and lonely. It now has a 6510 and, once I find the ROM files, will get a nice SD2IEC device to play some games! Quick note: I see your google drive is not available, any idea if/when i will be back?
I just picked up a C16 that doesn't boot, hoping it's the CPU given that's easier to replace than the TED. The CPU gets too hot to touch within seconds (using a 9V 1.33A DC wallwart I swapped the polarity on), while the TED stays stone cold. There's a Lotharek mod in the works called the "6502 plus 4", it's apparently an adapter board for the 7501/8501, that allows you to install a 6502 instead. It handles the I/O with CPLD logic, and also adds the Hannes 256KB RAM mod. It's still in preorder, so I've ordered a cheap China logic probe in the meantime in the hopes I can narrow the issue down with it. Maybe by the time the probe's here, and it does turn out the CPU's bad, the board's out. I don't mind FPGAs, but if the option of an actual 6502 CPU core is available, I'll go with that.
+Adrian Black, Good to know the CPU's more flaky than the TED. Yeah, I don't really want to make my retro computers mere hosts for FPGAs either (even though this might be inevitable in the distant future), but I don't mind it too much if the CPU core's at least still a real 6502 :)
So it looks like the enable line on one of the 2 decoders in the LS139 was bad. I don't think that any reasonable amount of schematic troubleshooting would have found that particular defect.
@@adriansdigitalbasement Possible, depends on the logic probe. But the desoldering/socketing approach was more effective. I used it myself not long ago when troubleshooting a ISA memory card. 3MB of RAM in 256kx1x9b banks. 1 bad chip among 108. And they were all soldered to begin with. Wasn't fun. :)
On a machine this simple, with so few chips, the shotgun approach is faster. BUT if you were trying to fix something with many more parts, then you'd want to try and trouble shoot it, at least to find the area that was bad, and then maybe try blindly replacing a few parts.
Hard lesson to learn :)
Great work. I love the C16 and seeing it running with a 6502 CPU is just phenomenal. But wouldn't it be possible to fix the external storage problem by connecting the pins of the CPU differently with the motherboard? So that no ROM-update is needed and even programs work that bypass the internal data transfer routines?
No, that is not possible. The CPU port on the 6510/8501 is 8-bit from the software side, but just 6 out of those 8 bits are physically available on pins. The problems is: The 8501 exposes a different subset of the 8 bits on the pins than the 6510. Therefore rerouting is not possible: There is no way to get the remaining two bits somewhere on a pin.
Thank you for your explanation. I think I now understand it. The C64 only uses 6 bits of an 8-bit port for data transfers but the C16 uses all 8 bits of this port. Geez. - I think he even said that in the video but I'm a bit slow on the uptake. :-)
Nice! I have a spare 4464 and am local if you want one!!
@@adriansdigitalbasement that is nice. I think i used unicorn to upgrade a 600xl.
Great part 2!
I like the way you trouble shoot the start up on the on the cpu pins.
I think I will try that on mine.
There is not a whole lot of info on start up trouble shooting as with the C64.
Is the reset circuit timer chip the same as the C64 (I think a dual 555)?
I actually have the minipro as you do. Used it heaps of times to find bad chips on the C64. I actually used it to verify the contents of the 2 kernal and basic chips on the C16 ..
I think I will spend some time re socketing and testing the smaller chips.
Thanks for the information....:-)
I just re-watched this video and was wondering if you could re-route the I/O pins on an adapter board (or maybe even in its current socketed form) to match the original KERNAL's expectations. As far as I can tell, the current "1:1" mapping is only done because this portion of the pinout more or less lines up nicely.
In a video situation like that, I'd say use the webcam to record the oscilloscope since that video stream will be shrunk down for the picture-in-picture and hide the poorer video quality. The main camera can be used for the big picture over the bench.
Can that Minipro EPROM programmer program a new PLA (such as one from Signetics) with the programming necessary to make a working replacement for a C64 PLA? At least one of my machines has a Signetics PLA, but from what I understand they have to be specifically programmed.
00Skyfox Logic array chips are completely different from EPROMs. I think it has been done, though one needs to find a chip with about the same propagation delay as the Signetics part.
Very interesting video Adrian, congrats! It would be nice if you can explain, in more detail, how is problem with the kernal and the pinouts. The C16 project is amazing, i just wonder what would be the performance difference between a C64 with your c16 with 64k ram upgrade.
I've got the same logic analyser, the software is rather odd and frustrating.
awesome Video :D
Brilliant !
You're great
2:12 "Overcloking" is that when you hide the processor in plain sight? ;-)
Genius !!! 😁
Hey Adrian, the modified kernels link does not work, any chance of an update to this?
Did i hear it right, did you say that because the expanded ram, that the C64 now functions like a real C64 ?
If so that would be amezing.
Hi! Another great video! I’m wondering which logic analyzer you purchased?
Adrian Black awesome thanks! Definitely reasonably priced! Just watched the pet rescue video. What a haul! You’ll have content for months !
Check out the Tynemouth blog for the different C16 64K methods (and it’s also a great blog too!)
blog.tynemouthsoftware.co.uk/2019/02/commodore-16-64k-upgrades.html?m=1
Adrian Black Serendipitous timing; I’d just been reading the blog and came to watch your video to see how you’d got on with the machine 👍
16k is too little? sounds like bill gates lol.. I remember when i used to code games on a zx81 with 1k ram :D certainly a good series though. keep up the work
I had one of these, and I frequently hit the 16K (actually 12K) limit just writing Basic programs. I used to hit the 48K limit on my Amstrad 464 later on too.
It's amazing that they even managed to get games to run in 16K.
I was a proud C16 owner as a child. One of the few advantages the C16 had was the V3.5 BASIC. It was so easy to do graphics. But when the graphical screen was used it literally ate about 10K of the 12K RAM leaving you with a pretty short programming space. That's why it's so little compared to the big brother Plus/4.
so, we need a 6502 + the extra 8 bit IO to have a base for a replacement for the c16 and c64 cpu. thextra pin we could use for a ram extension?
what about the cpu in the c128? is it the same like the 6510 but with higher speed?
You know i would love to start doing something like that as a hobby, but given the rarity of the old stuff i've been wondering what alternatives might be out there.
@@adriansdigitalbasementArduino was my first thought as well.
honestly i don't understand how commodore thought a completely uncompatible line of computers with all the existing software they had would've been successful. the c64 was already cheap enough and way better.
You lucky guy
I bought one of those 6510 adaptor pcbs off Him about a Year ago, I did have some issues with the sd2iec and some games, maybe the pi1541 I have yet to solder up will sort those problems out.
I assume You realise the TED can do NTSC or PAL? It is possible to do a switchable ntsc/pal mod for both. I think 90+ % of all software is Pal, so doing a mod is worthwhile. I bought three plus/4 machines a few Years ago off ebay, 2 are now modded for PAL. I'm in Australia so no need for NTSC here.
I think I was trying to load one of the newer games Majesty of Sprites or Land of Zador and it kept crashing during the load. I tried a few times made no difference. I'm certain the same games worked on my other plus/4 that has a real 8501. The Pi1541 may make a difference, but we'll see.
Is there anyway one can test a ted chip and a cpu without another working machine?
If you just gently sand down the top of the chip by using one of the proper sized kernal sanders, that might fix the problem. Most people a just too darn chicken to try it.
After the 6510 mod, remapped kernal ROM and 64k of RAM, is it really a C16 anymore?
"I left this in to show that it is easy to show how easy it is to go down the wrong path."
And you left that in to show how your delete key refuses to delete.
Adrian, is there a way to run the MiniPro over a MAC?
Why did that logic chip that you replaced go bad?
Link to chipreader does not work
Best way to fix a C16? Turn it into a C64, apparently.
11:09 maybe you didn't put it in the SCOKET correctly LOL
JiffyDOS is stil sold under license so it is probably illegal to disassemble it. It is also illegal to burn your own ROMs with JiffyDOS: www.go4retro.com/products/jiffydos/
Really appreciate your videos, they are really informative.
Please post a link to the programmer and the software.
Er... Ah... Thanks... But... Have the TL866A/CS been recalled?
re: www.autoelectric.cn