@38:15 "So I could have actually avoided so many of these pitfalls". I couldn't help but laugh after seeing you get several versions of 'PITFALL' on your ROM tester. Accidental comedy at its finest.
I like it when you include all the struggles. It feels super relatable unlike some videos that jump cut out all of the flops. Reading the manual after the struggle reminds me ot that line from Dr. Strange; "The warnings come after the spells!" Thanks for another fun one!
I also love it, this is the realistic process of debugging old stuff, on camera. At least when you have all the tools and spares Adrian has, but waiting for shipping arcane stuff from around the world would not make for exciting videos :D I'm quite envious of his setup !
Some of us love/loved the C128. I upgraded from a C64 in 1985 and immediately took to BASIC 7.0 coding. CP/M mode got me through college computer science, as the software we used in my early classes was also available for CP/M. GEOS 128 was perfect for writing my college papers, and Desterm for 80 col mode was perfect for my early internet use. I upgraded again to the 128DCR in 1989. Long live the Commodore 128!. P.S. The 128DCR differs from the flat C128 in that it has a full 64k of video memory, making it a 192k ram machine (not counting the drive buffer ram).
I had a C128 with 512k expansion ram, graphics ram expansion for Basic 8 coding, a 1541, 1571 and 1581 with the 1572 mouse. It got me all though college also and GEOS 128 was the bomb! I used Geo Publish to make our Commodore club newsletter and would output them as postscript and move them with Big Blue Reader to a floppy to print on laser at work! The best of times!!!!
Good call out on the 128 Geos, that thing was awesome I used it mainly for word processing and school work also. By the way there was a 128 Geos rom that I remember from the magazines back in the day, but never actually saw it in real life
Oh yeah. My C128 went into C64 mode only for games. I published a small press magazine using it (along with other computers - occasionally in C128 CP/M running WordStar), and wrote my first commercially-published software package, a C128-only 80 column mode BBS-focused terminal emulator. I also used apps like Paperback/Pocket Writer (again, 80 column mode) and as far as I was concerned this machine was an absolute beast, and C128 as C128 was the last great 8-bit. (Also you are correct, GEOS 128 was excellent and far better than the C64 version and I did use that a lot. That stayed in high-resolution all the time too.)
This video is hardly a "fiasco". Maybe from a repairing viewpoint, but as a video in itself I found it fun and entertaining to watch. There is something to be said watching failures that are actually part of the learning progression.
Hi. I think it's not a fiasco as you say, i learned lots of things.. And usually is when you have issues and you try to solve that you have value and experience, so i can say it's a total success! Thanks for your contribute!!
Whenever you test keyboards and type in the prompt, I always wish you’d type, “the quick brown fox jumps over the lazy dog”. That way you can text the whole alphabet keys at least. Just something I think of every time lol. Take it or leave it, you know I adore your videos. So proud that I can support you on Patreon. Keep it up, Adrian!
Heh that's not a great test IMHO, because most of the time I want to test the switches and typing each letter twice lightly can help identify switch bounce or dodge keys where it might work once but skip a letter.
It's a classic test dating all the way back from the telex machines, maybe even typewriters before that. Perhaps it doesn't find glitchy keys, but at least it finds the dead ones in the English alphabet.
Thanks for featuring the mighty C128 again! Side notes: The SID on your model is a 8580R5 (it’s a 6581 on other motherboards), and that Z80 seems a 6 MHz model, although it runs at "half 4MHz", i.e. 4 MHz half of the time for an effective 2 MHz (check with oscilloscope) due to VIC-IIe bus access priority. I believe it could have been possible to run the Z80 at full 4 MHz when the VDC was in use instead of the VIC-IIe, but that would have probably required more logic. Note that CP/M mode was there just because the C64 CP/M cartridge was not working on the C128, and Commodore marketing wanted an extra check mark on the specs. Well, at least we had some extra fun with the Z80 in the C128!
Errors, mistakes and screw ups are a good way to learn. When things just work right, we don't necessarily know why and we don't learn a thing. This is a good video for us to learn from. First lesson: read the manual! 😀 Just teasing.
With all the fake masculinity these days: Reading the manual /first/ is what a /true/ man does, because sometimes doing it right the first time trumps effing around with your pride doing it wrong for hours until one finally opens the manual 😅
I've been watching your channel for a few years now. I really enjoy your content. I really do not have the time or the budget to satisfy my desire to tinker with retro equipment. Therefore I live vicariously through you. I appreciate your work.
I still have one of those C128DCR's. I found it in, of all places, a computer recycling warehouse. It was in a badly waterlogged commodore box, wrapped up in plastic, with the keyboard. Needless to say, I made it disappear from the warehouse. It works perfectly, except for the floppy drive. Once in a while it'll work, but it mostly whines and will not read a floppy. Bummer. Keep up the good work!!
I have. I think it's the bearings in the spindle motor that are bad. I also haven't tried taking it apart too much, not wanting to make it completely inoperable. It'd be nice to have a working 1571, as I have two other 1571's that no longer read either.
Adrian your videos are truly awesome, even when everything goes wrong you still pull a rabbit out of the hat, when my projects often something is on fire or the mains power trips out.
You may be too young for this memory, but your video reminds me of the Johnny Carson Show. There were times when he would do a monologue that would bomb, but it would end up being funnier than if all the jokes that were written were a hit. In other words, I enjoy you sharing your learning experience with us. Your speaking of the difficulty of talking while also doing your testing, or preforming other tasks, during your video, while also acting as the producer and the director, reminds me of when I was a flying instructor on supersonic aircraft with the USAF in the 1970s. While flying, the expected procedure was, to talk about every action you were planning and accomplishing, while at the same time, flying manoeuvres at speeds often exceeding 8 miles a minute often in close formation). It became a more natural thing after a lot of practice, and thankfully, only had to be performed for the check pilot on our annual proficiency checks.
I'm pretty sure I've seen those eraser 'pencils' at office / art supply stores in the past. There is also a version that works like a mechanical pencil (with replaceable eraser sticks), which I have at work, and yes, it REALLY comes in handy cleaning off edge connectors!
I love that you have videos like this and don't cut out the struggles because I know I've done similar with my own projects even with just sticking to DOS/Win98 and newer
I thoroughly enjoy your troubleshooting videos. Please don't edit this out. This is a perfect real life example of how things can go wrong. Documentation is SO important when doing work like this. I have found myself writing a repair diary and narrative on my repairs and things I noticed along the way. Thanks Adrian.
Loved the video. You may have noted that, while it seemed pretty slow in 80 column mode in CP/M, it was still faster than in 40 columns. That's because it runs in FAST mode at 2MHz in 80 cooumn mode. The Z80 is technically 4MHz but limited to 2MHz due to its reliance on the CBM chips.
My favorite thing about your work Adrian is how you'll gladly show us where you screw up, admit it, and then (assuming you know) show us how to avoid your pitfalls.
I have a very clean 128D that I was given around 20 years ago, without the keyboard. I tested it a long time ago with just a power-up, and it seemed fine. I've bought a German keyboard for it but I need to get the machine out again and *finally* test it for real. This video gives me a little push.
You should take this show on the road, man. Showing us your mistakes is so very educational. I don't generally work Commodore hardware, but all systems tend to have little quirks listed in some dusty corner of the documentation, so RTFM (Read The Fine Manual) really does pay dividends. This video drove that home quite nicely. You might try a breakout connector? That should allow you to try different combinations of jumpers to get where you need to be on the keyboard port.
A minor thing, but a couple of things I like about your channel (apart from the content of course) is 1) your short intro and 2) your ident, which fits into 3) it's not badly normalized audio-wise (so many horrible examples of idents blasting distorted with too low mic audio, it hurts)
"Naval Jelly" (thickened phosphoric acid) is the product of choice for rust mitigation. It converts red iron oxide to black iron phosphate. The phosphate isn't impermeable to moisture, so it still needs primer/paint, but it will stop the rust.
Always interesting to see C=128 content, as it was pretty rare even when new. Have seen 128 only twice in my life in the 80's, once for the original flat 128 and another time for 128D. Only one time for Commodore 16 as well, but lots of Commodore 64's, including the one I had, C-64 C. Actually from the people I knew in the 80's, mine was the only C-model, all others had the original bread bin C-64.
38:20 It's the same problem for streamers! Especially having to do live self tech support because there's always a problem, and its always a new problem.
I remember seeing these in stores. My family was planning to get one, then saw the Amiga 500 and decided to go for that one instead. That was definitely the right decision in early 1989.
I had this exact machine back in college. It started getting glitchy and I scrapped it a little over two decades ago. One of my biggest regrets. I really wish I'd kept it and given it another chance.
The Commodore 128 was three computers in one. A C64, a Z80 and a C128. the floppy is another computer. When the C128 came out the Z80 software was already out of date. There were hardly any applications for the C128. What was left was just the C64 compatibility mode.
(6:45) I have an 128-D european model, with plastic case, (which I bought second hand in the early 90's). This european model does have a 2.36" 'Panaflo' fan as standard. But it is EXTREMELY ULTRA-MEGA-NOISY, 😵💫 to the point that it was impossible to think and work (writing or programming) in front of the unit. It was infuriating. I guess the metal case of the 'cheap' version helped to dissipate somewhat better the heat from the power supply, and that's probably why they decided to do without the fan, (further reducing costs, and saving US users unbearable noise in the process). 👋
Hi, nice video. Seeing the 128DCR working still. My first own computer. BTW, a 25 pin SCSI cable is not necessarily 1:1 straight through. It’s only 8data lines some additional signals and a bunch of grounding for each signal as twisted pairs on good cables. I had a bunch of old scsi cables from my old servers and macs and needed to repurpose one a couple of years ago for som project that needed like 16 signals and 5 lines for power and ground and there wasn’t enough pairs there because almost half the pins were „shorted“ as a common ground and not just straight through - most likely to make the cable not too stiff with 25 connections.
Well, I tend to "get right to it" first and do the reading (if necessary) later if I should not manage to get something working, so I really understand you struggeling with both the test harness and the diagnostic rom😄
My first machine back in the day and few years back reacquired another C128DCR. I had to fashion the same kind of keyboard adapter until I found a proper 128D keyboard years later
This happens in software, too. You write some code, you write tests for it, you get test failures left and right…and after much struggle, it turns out that it's the _tests_ that aren't right, and the code being tested was working perfectly the whole time.
I love the C128 even though yes, I mainly used it in C64 mode. I always wanted a D or DCR but yeah, never got one. Also, I think that if you were trying to avoid pitfalls I think you failed in more ways than one. ;) I also realised that I need to get myself an EEPROM programmer. That would be so handy for so many things, especially our C128 which has fallen into disrepair (keyboard wasn't working properly when we stored it so I guess an IC has gone bad and just needs replacing) so getting it tested would be nice. Great video, Adrian. Merry Christmas./Gleðilig jól.
The 'plastic' 128D using the same board as the 'flat' 128 was designed together with the 'flat' 128. The original board has a hole and some modifications specifically to allow for the original 128D (as per Bil Herd) 128DCR PSU tends to be very reliable and not go overvoltage, but note there exist at least 3 different PSUs. None are known to go overvoltage on failure. Seeing how yours still has the cutout for installing a fan, it is not the newest 'even more cost reduced' power supply. The biggest issue with the PSU is the PCB being rather brittle and easy to damage or break. Be really carefull when removing/reinstalling it. I strongly suggest installing a low noise fan which can run from 5v (at a lower rpm). You don't need a lot of airflow, but just that little bit of airflow will help the power supply, and the nearby vic2 and vdc chips a lot. Commodore made those machines with an expected lifespan of some 5 years... and for that you don't need the fan. But to make it last... that little fan really helps. The mounting holes for the fan are non standard size, and I'd actually rather suggest to use some silicone glue or such to stick it in place, and at the same time provide some accoustic insulation between the fan and the case. I actually validated the prototype of Sven's diag harnass for the 128, and can confirm it fully works with a DCR provided a longer cable for the cassette port connector. But keep in mind the 128DCR case leaves no room for the 'ears' of modern versions of that connector. That is a problem when testing a board while it is in its case. Ah yes... CP/M actually is using a virtual terminal which is bandwidth limited, and pretty similar to using a 2400bps terminal. There is a way to increase its speed, but it won't ever be fast with CP/M... It can however be rather fast with a proper 'driver'. I have done quite a bit of development of software using it. During the last Commodore Users Europe 'online' meeting I did a 20 min presentation about one of my projects (OS128) which shows how fast VDC output can be, even with a multitasking OS. It has some '2d acceleration' functionality which is not used by the Commodore roms or CP/M, but when used properly can make a huge difference. An interesting and little known trick is to use rle compression when transferring data to it, and use its hardware fill capability to 'expand' the rle data. This saves bandwidth, and even when 'realtime' encoding the data, is often faster.
I chuckled a bit when you talked about all the 'pitfalls' in your testing of the computer (after the segment where you kept rebooting that cartrdidge) :)
I just took possession of an original case 128D (with the keyboard). It's of unknown working condition so this video gave me at least some ideas of what I might be up against.
I had one of these in my youth. My Sid chip kept dying on it. Other than that, it was a champ! Miss it. I also wired up the 80 column display myself to a new tv. Not bad for a 14 year old who just read the manual and hoped.
My thought as to making a keyboard adapter for the 128 to 128DCR... you can get right-angle pin headers - one row against the board then get a version with longer tails for thicker PCBs, then stagger the pads and stack that on top. Then on the other side a standard DB-25 connector. I'm sure it would be a simple layout exercise in most any PC board CAD app (like KiCAD)...
The plastic C128D is sometimes nicknamed C128 Diesel because of its rather noisy fan. :) You are correct that there are normal C128 and 1571 motherboards inside the plastic C128D. AFAIK no C128DCRs ever left the factory with a fan.
As soon as I saw that this was about a 128D, my first thought was that the CIAs are likely bad. That was the problem with my 128D when I got it. I had to replace both of them to get it to boot at all. It's apparently common due to missing or poorly designed static protection circuitry on the keyboard and joystick connectors. I'm surprised at how good of condition this unit is in, with no major issues.
Those eraser pencils with the brush on the back were common back in the day in typing classes (before PCs). You used them to erase mistakes on things you typed.
The 128DCR is pretty much the most unreliable machine Commodore has ever built. I worked for a metalworking company in '90/'91 whose cutting machines were CP/M controlled. The only way to get CP/M machines here in Germany at that time was with c128s. The 128DCRs failed on average after about 3-4 months of continuous operation, while 2 old 128Ds (built in '85 + '86) were still running without any problems. These were also the only two machines that lasted until the company switched to BSD-based computers in 1997. However, storing DCRs for years was never a problem, our company had kept 20 in stock since 1990 to compensate for failing ones.
Diagnostics are really only reliable if you know how they test what they test. For example, some ram tests may pass, while others on the same exact ram might not pass. Testing methodology matters. I think my favorite old computer diagnostic tool was the "G-er." This was literally a DB-25 with a toggle switch on it and some pins jumpered inside. What it did was print upper case G's or if you flipped the toggle switch, lower case g's. This was a quick and dirty test to see if your dot matrix printer had a stuck pin or bad pin driver. G was particularly useful as it had descenders on the lower case g. Kind of like a printer loopback plug.
Great video as always Adrian. Have you ever consider making a video of your setup? aka what software you use in the modern PC of the basement and its periferals and the various gadgets or adapters for the diferents machines you fix?
The main processor in the C128 is actually a MOS 8502 ( en.wikipedia.org/wiki/MOS_Technology_8502 ). It's _almost_ the same as the MOS 6510 in a C64, but not _quite_ (much as the MOS 6510 was mostly the same as a MOS 6502). I'm curious if the C128 used that "P6" signal for anything.
Adrian, that final screen from the demo... the only thing that could possibly make sense is that the SX-64 portable was called the Executive-64 in some regions. But 96 colors? Wow, there's a long distance between a 1 and a 9 on a keyboard. That's a hell of a typo. And let's not even talk about the Apple part.
Hi Adrian! I just ordered my first flat 128 so this video is very timely, informative and useful to me! I have the versa cart cartridge with all the diagnostic tools so I should be all set in case I need to troubleshoot any issues! I just received a 1571 drive and it seems to read a few of the floppies I have but being bought on eBay, I have no idea if they are any good or even erased! What is the name of the donkey kong game you run, seems like the best SID tester! Thanks for all the videos!
The keyboard adapter comes in handy for SX-64, too...even easier. If you got the SX-keyboard cable, all it takes is a gender changer to use the C128D-Keyboard on SX64 I know, usually the SX cable is missing, but that´s a straight through, as far as I remember. So one could even get rid of the gender changer and use a standard 25P-cable with C128 KeyB. You´ll need a dremel though to make a 25-pin fit on SX
Hi I am loving your channel just wondering what do you do with all the machines that you fix and are they still useful today or are they just cool retro things to have around and save Thanks Peter from Perth Australia
The fan was going to be there but was pulled at the very last moment to save money. Bil Herd talks about it in a video that the C128DCR was done, and he moved to working on the 264 line (plus/4, C16 & C116). He said it was much later that he found out they had removed the fan. Here is a SHORT video of a photo collage of me installing a fan (Noctua 60 X 25mm) into my C128DCR on May 19, 2022 and a video of what it looks like done and the fan start up and shut down. ua-cam.com/users/shortsRgwsc672yjY?feature=share
I had a 128 as a kid. It's true that 128 mode mostly went un-used. There was one killer feature though, 80 columns on a terminal program for calling BBSes, and word processors. By the late 80s and into the early 90s having only 40 columns of text was a pretty big limitation. There were a few programs that could sort of fake 80 columns of text by using graphics mode instead of text mode, but the text was not very sharp, and hard to read. So having 80 columns of sharp text was sort of huge for these two reasons. IIRC I even lent mine to a friend to use as his terminal in the mid 90s, so he could connect to the early internet, and read email, get on IRC, etc.
One thing that joystick tester doesn't seem to test is the POT X/Y operation which comes from the SID and can often be bad. Really should try some paddle tests on those ports... I managed to get a working 128 DCR as part of a massive Commodore salvage haul several years ago and it's my pride and joy. LOVE it! Good mod is to make a couple little dip-switches hooked to the (cuttable) pad/traces on the MB that control the drive number for the internal. I cut mine to to set it to Drive 10 as I always run everything from a Ultimate2+ Cart instead of messing around with real floppies anymore.... Missing keyboard is also a big problem with Amiga 1000's found these days. The keyboards rarely were kept around... :( And it's tough to find a replacement or even something that can be adapted to work.
The problem with the Z80 on the 128 and the CP/M Cartridge for the C64, is that the Z80 is running at the same speed as the 6510 of 1MHz, when CP/M Machines were running between 3.5 and 7MHz. The 6502 at the same clock speed, rund 4X faster than the Z80 and 8080/8088/8086 because what takes 1 to 3 clock cycles while the Z80/8080/8086/8088 uses 4 to 8 clock cycles for the same or similar machine code. It is Commodore's mistake in running the Z80 at the same clock peed as the 6510 when they could have put in a separate clock for it. 40colums on CP/M Being bad? Again, many CP/M machines of the time has a strange 32X16 or 64X16 screen, so compared to that, 40 would be in the middle of the two. Remember, for its time, CP/M was the leading OS for more than a decade and if it were not for a marketing mistake, would be the leading OS to this day. It is not stated but the System on the Atari ST is CP/M Based, using GEM on top of its DOS, which for Digital Research was modified version of CP/M.
The Z80 in the C128 does not use the same clock as the 6510. The Z80 has a 4Mhz clock and runs at that speed the problem is that (and some one correct me here if this is not 100% accurate) the Vic II is still running in slow mode (1mhz instead of 2) and the Vic is doing the memory refresh for the DRAM so on half of the 4Mhz Z80 cycles the Vic halts the Z80 to do it’s thing, which renders the effective speed of the Z80 to around 2Mhz, which indeed is very slow.
Hi Adrian. It may be that the cassette port loop-back connector was deliberately designed on the C128D so the old one won’t fit due to changes in the electrical specifications; it’s not just the mounting tabs (ears)! Just guessing, here.
Control ports fail when the keyboard lines are FUBAR because they share the ports on CIA 1. A well-known issue on the 64/128 is a joystick in port 1 causing phantom keypresses if wiggled.
I wonder if theres gonna be a channel in 20, 30, 40 years doing this kind of work with computers we use now. Imagine someone performing a resurrection on a threadripper or xeon they found in the trash for free.
Yes! The 8-bit dance party is always awesome to see. I have a C128 sitting in a closet but it isn't working due to the power switch being messed up (I wouldn't be surprised if some traces were in rough shape too, as it hardly ever booted into C128 mode, but C64 mode would work fine). I have zero experience working on electronics so I have no way to repair it. On a side note... Seeing that the C128 machines have an 80 column mode, do you think someone out there might make an 80 column version of the 8-bit dance party? It would be a lot of work, I'm sure, but that would be a pretty nice way to make sure that the 80 column mode on any C128 that you work on is functioning properly (especially if such a version let you press a key to change the colors used).
@38:15 "So I could have actually avoided so many of these pitfalls". I couldn't help but laugh after seeing you get several versions of 'PITFALL' on your ROM tester. Accidental comedy at its finest.
I like it when you include all the struggles. It feels super relatable unlike some videos that jump cut out all of the flops. Reading the manual after the struggle reminds me ot that line from Dr. Strange; "The warnings come after the spells!" Thanks for another fun one!
I also love it, this is the realistic process of debugging old stuff, on camera. At least when you have all the tools and spares Adrian has, but waiting for shipping arcane stuff from around the world would not make for exciting videos :D
I'm quite envious of his setup !
But he does cut out a lot of stuff I would like to see
Amen
Some of us love/loved the C128. I upgraded from a C64 in 1985 and immediately took to BASIC 7.0 coding. CP/M mode got me through college computer science, as the software we used in my early classes was also available for CP/M. GEOS 128 was perfect for writing my college papers, and Desterm for 80 col mode was perfect for my early internet use. I upgraded again to the 128DCR in 1989.
Long live the Commodore 128!.
P.S. The 128DCR differs from the flat C128 in that it has a full 64k of video memory, making it a 192k ram machine (not counting the drive buffer ram).
I had a C128 with 512k expansion ram, graphics ram expansion for Basic 8 coding, a 1541, 1571 and 1581 with the 1572 mouse. It got me all though college also and GEOS 128 was the bomb! I used Geo Publish to make our Commodore club newsletter and would output them as postscript and move them with Big Blue Reader to a floppy to print on laser at work! The best of times!!!!
GEOS 128 was amazing, and BASIC 7 was so good that I was able to start writing my own programs with it, instead of copying ones out of magazines.
Good call out on the 128 Geos, that thing was awesome I used it mainly for word processing and school work also. By the way there was a 128 Geos rom that I remember from the magazines back in the day, but never actually saw it in real life
I remember using my C128 to BBS and write stuff in Wordstar. After my C128 died I scrounged up a TRS80 model 2 with four 8" floppies.
Oh yeah. My C128 went into C64 mode only for games. I published a small press magazine using it (along with other computers - occasionally in C128 CP/M running WordStar), and wrote my first commercially-published software package, a C128-only 80 column mode BBS-focused terminal emulator. I also used apps like Paperback/Pocket Writer (again, 80 column mode) and as far as I was concerned this machine was an absolute beast, and C128 as C128 was the last great 8-bit. (Also you are correct, GEOS 128 was excellent and far better than the C64 version and I did use that a lot. That stayed in high-resolution all the time too.)
I prefer the struggle, it’s not like im watching this to learn, I’m here for the emotional rollercoaster of hardware diagnostics!
This video is hardly a "fiasco". Maybe from a repairing viewpoint, but as a video in itself I found it fun and entertaining to watch. There is something to be said watching failures that are actually part of the learning progression.
Hi. I think it's not a fiasco as you say, i learned lots of things.. And usually is when you have issues and you try to solve that you have value and experience, so i can say it's a total success! Thanks for your contribute!!
Whenever you test keyboards and type in the prompt, I always wish you’d type, “the quick brown fox jumps over the lazy dog”. That way you can text the whole alphabet keys at least. Just something I think of every time lol. Take it or leave it, you know I adore your videos. So proud that I can support you on Patreon. Keep it up, Adrian!
Heh that's not a great test IMHO, because most of the time I want to test the switches and typing each letter twice lightly can help identify switch bounce or dodge keys where it might work once but skip a letter.
It's a classic test dating all the way back from the telex machines, maybe even typewriters before that. Perhaps it doesn't find glitchy keys, but at least it finds the dead ones in the English alphabet.
Thanks for featuring the mighty C128 again! Side notes: The SID on your model is a 8580R5 (it’s a 6581 on other motherboards), and that Z80 seems a 6 MHz model, although it runs at "half 4MHz", i.e. 4 MHz half of the time for an effective 2 MHz (check with oscilloscope) due to VIC-IIe bus access priority. I believe it could have been possible to run the Z80 at full 4 MHz when the VDC was in use instead of the VIC-IIe, but that would have probably required more logic. Note that CP/M mode was there just because the C64 CP/M cartridge was not working on the C128, and Commodore marketing wanted an extra check mark on the specs. Well, at least we had some extra fun with the Z80 in the C128!
38:10 "... maybe I could have avoided so many of these Pitfalls..." Hey, I enjoyed all the times you ended up in Pitfall in this video!
Sometimes you win and sometimes you learn. Definitely a learning experience for ya!
I love the Commodore 128 content. That was my computer as a kid, so many afternoons playing games with friends and writing Basic and ASM programs
The sprite and drawing support was amazing on the 128, it was such a fun machine
Errors, mistakes and screw ups are a good way to learn. When things just work right, we don't necessarily know why and we don't learn a thing. This is a good video for us to learn from. First lesson: read the manual! 😀 Just teasing.
SO many times I almost wiped my uncle's hard drive while figuring out DOS in my early teens, I can relate. Thank the hells for undelete back then lol
With all the fake masculinity these days: Reading the manual /first/ is what a /true/ man does, because sometimes doing it right the first time trumps effing around with your pride doing it wrong for hours until one finally opens the manual 😅
Read the manual but don't think it's gospel. Sometimes there are critical errors in them.
I feel like that’s especially true of computers of this era.
@@ax14pz107 true. That’s when the student becomes aware. One of the best experiences ever to figure out that an errata is needed.
I've been watching your channel for a few years now. I really enjoy your content. I really do not have the time or the budget to satisfy my desire to tinker with retro equipment. Therefore I live vicariously through you. I appreciate your work.
I still have one of those C128DCR's. I found it in, of all places, a computer recycling warehouse. It was in a badly waterlogged commodore box, wrapped up in plastic, with the keyboard. Needless to say, I made it disappear from the warehouse. It works perfectly, except for the floppy drive. Once in a while it'll work, but it mostly whines and will not read a floppy. Bummer. Keep up the good work!!
Did you try to service that floppy drive? It might be something simple
I have. I think it's the bearings in the spindle motor that are bad. I also haven't tried taking it apart too much, not wanting to make it completely inoperable. It'd be nice to have a working 1571, as I have two other 1571's that no longer read either.
Adrian your videos are truly awesome, even when everything goes wrong you still pull a rabbit out of the hat, when my projects often something is on fire or the mains power trips out.
Such a great video. Everyone has skimmed over information only to find out later they missed something very important.
**Adrian*** You being tripped by the harness and your 128D quirks just adds to the entertainment
You may be too young for this memory, but your video reminds me of the Johnny Carson Show. There were times when he would do a monologue that would bomb, but it would end up being funnier than if all the jokes that were written were a hit. In other words, I enjoy you sharing your learning experience with us.
Your speaking of the difficulty of talking while also doing your testing, or preforming other tasks, during your video, while also acting as the producer and the director, reminds me of when I was a flying instructor on supersonic aircraft with the USAF in the 1970s. While flying, the expected procedure was, to talk about every action you were planning and accomplishing, while at the same time, flying manoeuvres at speeds often exceeding 8 miles a minute often in close formation). It became a more natural thing after a lot of practice, and thankfully, only had to be performed for the check pilot on our annual proficiency checks.
I'm pretty sure I've seen those eraser 'pencils' at office / art supply stores in the past. There is also a version that works like a mechanical pencil (with replaceable eraser sticks), which I have at work, and yes, it REALLY comes in handy cleaning off edge connectors!
For sure, they’re incredibly easy to find at any Michael’s or Blick’s or other arts/crafts store! Super handy to have around.
I love that you have videos like this and don't cut out the struggles because I know I've done similar with my own projects even with just sticking to DOS/Win98 and newer
I thoroughly enjoy your troubleshooting videos. Please don't edit this out. This is a perfect real life example of how things can go wrong. Documentation is SO important when doing work like this.
I have found myself writing a repair diary and narrative on my repairs and things I noticed along the way.
Thanks Adrian.
Watching your missteps is more informative for a neophyte than a flawless presentation, your process of elimination is always a good watch!
The 128 is the 8 bit computer I always wanted back in the day but never managed to get one. Great to see this survivor still running well!
Loved the video. You may have noted that, while it seemed pretty slow in 80 column mode in CP/M, it was still faster than in 40 columns. That's because it runs in FAST mode at 2MHz in 80 cooumn mode. The Z80 is technically 4MHz but limited to 2MHz due to its reliance on the CBM chips.
The C128D was my first home computer and I loved it and used it for over 5 years. Never had a single problem with it.
My favorite thing about your work Adrian is how you'll gladly show us where you screw up, admit it, and then (assuming you know) show us how to avoid your pitfalls.
Avoiding Pitfall is as easy as selecting the right DIP switch settings =)
Loved the comment you said about avoiding the pitfalls. Best pun ever
That's just freakin' awesome that you were to get a 128DCR!! I can't believe your luck!! Congrats on your new acquisition!
I have a very clean 128D that I was given around 20 years ago, without the keyboard. I tested it a long time ago with just a power-up, and it seemed fine. I've bought a German keyboard for it but I need to get the machine out again and *finally* test it for real. This video gives me a little push.
15:48 we used to use those in my typewriting class, we weren’t allowed to use Tippex (‘White-out’?)
Well I for one will remember about the keyboard dongle issue. It's the errors and troubleshooting that I enjoy the most. Have a Merry Christmas!
You should take this show on the road, man. Showing us your mistakes is so very educational. I don't generally work Commodore hardware, but all systems tend to have little quirks listed in some dusty corner of the documentation, so RTFM (Read The Fine Manual) really does pay dividends. This video drove that home quite nicely.
You might try a breakout connector? That should allow you to try different combinations of jumpers to get where you need to be on the keyboard port.
it's great to see you stepping up your diagnostic game since you've been full time! keep up the great vids!
A minor thing, but a couple of things I like about your channel (apart from the content of course) is 1) your short intro and 2) your ident, which fits into 3) it's not badly normalized audio-wise (so many horrible examples of idents blasting distorted with too low mic audio, it hurts)
Well done man, do not be so hard on yourself.👍👍
"Naval Jelly" (thickened phosphoric acid) is the product of choice for rust mitigation. It converts red iron oxide to black iron phosphate. The phosphate isn't impermeable to moisture, so it still needs primer/paint, but it will stop the rust.
Always interesting to see C=128 content, as it was pretty rare even when new. Have seen 128 only twice in my life in the 80's, once for the original flat 128 and another time for 128D. Only one time for Commodore 16 as well, but lots of Commodore 64's, including the one I had, C-64 C. Actually from the people I knew in the 80's, mine was the only C-model, all others had the original bread bin C-64.
I love your videos informative and totally honest. A treat for sure...
38:20 It's the same problem for streamers! Especially having to do live self tech support because there's always a problem, and its always a new problem.
That's really the nice thing about 80's tech. It was built to last.
I remember seeing these in stores. My family was planning to get one, then saw the Amiga 500 and decided to go for that one instead. That was definitely the right decision in early 1989.
I had this exact machine back in college. It started getting glitchy and I scrapped it a little over two decades ago. One of my biggest regrets. I really wish I'd kept it and given it another chance.
The Commodore 128 was three computers in one. A C64, a Z80 and a C128.
the floppy is another computer.
When the C128 came out the Z80 software was already out of date.
There were hardly any applications for the C128.
What was left was just the C64 compatibility mode.
No.
(6:45) I have an 128-D european model, with plastic case, (which I bought second hand in the early 90's).
This european model does have a 2.36" 'Panaflo' fan as standard. But it is EXTREMELY ULTRA-MEGA-NOISY, 😵💫 to the point that it was impossible to think and work (writing or programming) in front of the unit. It was infuriating.
I guess the metal case of the 'cheap' version helped to dissipate somewhat better the heat from the power supply, and that's probably why they decided to do without the fan, (further reducing costs, and saving US users unbearable noise in the process). 👋
Hi, nice video. Seeing the 128DCR working still. My first own computer. BTW, a 25 pin SCSI cable is not necessarily 1:1 straight through. It’s only 8data lines some additional signals and a bunch of grounding for each signal as twisted pairs on good cables. I had a bunch of old scsi cables from my old servers and macs and needed to repurpose one a couple of years ago for som project that needed like 16 signals and 5 lines for power and ground and there wasn’t enough pairs there because almost half the pins were „shorted“ as a common ground and not just straight through - most likely to make the cable not too stiff with 25 connections.
Well, I tend to "get right to it" first and do the reading (if necessary) later if I should not manage to get something working, so I really understand you struggeling with both the test harness and the diagnostic rom😄
My first machine back in the day and few years back reacquired another C128DCR. I had to fashion the same kind of keyboard adapter until I found a proper 128D keyboard years later
I know you said you could have avoided some pitfalls, but I enjoyed seeing Pitfall on the cartridge
This happens in software, too. You write some code, you write tests for it, you get test failures left and right…and after much struggle, it turns out that it's the _tests_ that aren't right, and the code being tested was working perfectly the whole time.
47:00 WTF? it is definitely a 8580 -- it sounds almost perfect (ofc it was composed for PAL and you play it in NTSC)
The 8 bit dance party tempo was truckin today!
NTSC FOR LIFE! We livin’ in the 60 Hz land, baebee!
I love these types of videos. We are all guilty of the same series of events for various reasons.
Enjoyable to watch
was very cool to see cpm running on that thing! who knew. Great video as usual
I love the C128 even though yes, I mainly used it in C64 mode. I always wanted a D or DCR but yeah, never got one. Also, I think that if you were trying to avoid pitfalls I think you failed in more ways than one. ;) I also realised that I need to get myself an EEPROM programmer. That would be so handy for so many things, especially our C128 which has fallen into disrepair (keyboard wasn't working properly when we stored it so I guess an IC has gone bad and just needs replacing) so getting it tested would be nice.
Great video, Adrian. Merry Christmas./Gleðilig jól.
Yes, many Pitfalls. I think I counted four of them?
Hi, Adrian. Have a merry Christmas and a happy new year to you and your family. Stay safe too. This video was a fun one thank you.
Loved the video!!! I have a 128D that I now want to work on and see how it is.
Loved the video. Some actual broken c128 repairs would be awesome. Of course you have to have some broken c128s for that to happen :)
Best to show the mistakes, so we don’t make them, I learn a lot from your channels. Merry Xmas John(uk)
The 'plastic' 128D using the same board as the 'flat' 128 was designed together with the 'flat' 128. The original board has a hole and some modifications specifically to allow for the original 128D (as per Bil Herd)
128DCR PSU tends to be very reliable and not go overvoltage, but note there exist at least 3 different PSUs. None are known to go overvoltage on failure. Seeing how yours still has the cutout for installing a fan, it is not the newest 'even more cost reduced' power supply. The biggest issue with the PSU is the PCB being rather brittle and easy to damage or break. Be really carefull when removing/reinstalling it.
I strongly suggest installing a low noise fan which can run from 5v (at a lower rpm). You don't need a lot of airflow, but just that little bit of airflow will help the power supply, and the nearby vic2 and vdc chips a lot.
Commodore made those machines with an expected lifespan of some 5 years... and for that you don't need the fan. But to make it last... that little fan really helps.
The mounting holes for the fan are non standard size, and I'd actually rather suggest to use some silicone glue or such to stick it in place, and at the same time provide some accoustic insulation between the fan and the case.
I actually validated the prototype of Sven's diag harnass for the 128, and can confirm it fully works with a DCR provided a longer cable for the cassette port connector. But keep in mind the 128DCR case leaves no room for the 'ears' of modern versions of that connector. That is a problem when testing a board while it is in its case.
Ah yes... CP/M actually is using a virtual terminal which is bandwidth limited, and pretty similar to using a 2400bps terminal. There is a way to increase its speed, but it won't ever be fast with CP/M... It can however be rather fast with a proper 'driver'. I have done quite a bit of development of software using it. During the last Commodore Users Europe 'online' meeting I did a 20 min presentation about one of my projects (OS128) which shows how fast VDC output can be, even with a multitasking OS. It has some '2d acceleration' functionality which is not used by the Commodore roms or CP/M, but when used properly can make a huge difference. An interesting and little known trick is to use rle compression when transferring data to it, and use its hardware fill capability to 'expand' the rle data. This saves bandwidth, and even when 'realtime' encoding the data, is often faster.
ahah I do the same all the time. Missing that important information and spending buckets of time on something! Nice video!
The C128D was great for BBS'ing back in the day with 80 columns and software like DesTerm.
I chuckled a bit when you talked about all the 'pitfalls' in your testing of the computer (after the segment where you kept rebooting that cartrdidge) :)
I used to love the 128D's They were good little machines.
I need to find another working one. I miss mine. It was as tweaked as one could.
Merry Christmas happy holidays Adrian all the best and the tech bunker
I just took possession of an original case 128D (with the keyboard). It's of unknown working condition so this video gave me at least some ideas of what I might be up against.
I had one of these in my youth. My Sid chip kept dying on it. Other than that, it was a champ! Miss it. I also wired up the 80 column display myself to a new tv. Not bad for a 14 year old who just read the manual and hoped.
Your title describes my channel pretty well. :) I like to see all the details. If people don't want to see the detail, they can fast forward...
My thought as to making a keyboard adapter for the 128 to 128DCR... you can get right-angle pin headers - one row against the board then get a version with longer tails for thicker PCBs, then stagger the pads and stack that on top. Then on the other side a standard DB-25 connector. I'm sure it would be a simple layout exercise in most any PC board CAD app (like KiCAD)...
In Germany back in the days, Mercedes Benz Diesel were very popular.
Well, we called it 128 Diesel.
The plastic C128D is sometimes nicknamed C128 Diesel because of its rather noisy fan. :)
You are correct that there are normal C128 and 1571 motherboards inside the plastic C128D.
AFAIK no C128DCRs ever left the factory with a fan.
I noticed it does warm up a little but overall runs quite cool
As soon as I saw that this was about a 128D, my first thought was that the CIAs are likely bad. That was the problem with my 128D when I got it. I had to replace both of them to get it to boot at all. It's apparently common due to missing or poorly designed static protection circuitry on the keyboard and joystick connectors. I'm surprised at how good of condition this unit is in, with no major issues.
I remember using those pencil type erasers in typing class way back in the day.
That Christmas demo really brings back memories
I think you should install a fan where the space for one is. Cooling would be great for the rare electronics inside.
Those eraser pencils with the brush on the back were common back in the day in typing classes (before PCs). You used them to erase mistakes on things you typed.
The 128DCR is pretty much the most unreliable machine Commodore has ever built.
I worked for a metalworking company in '90/'91 whose cutting machines were CP/M controlled.
The only way to get CP/M machines here in Germany at that time was with c128s.
The 128DCRs failed on average after about 3-4 months of continuous operation, while 2 old 128Ds (built in '85 + '86) were still running without any problems.
These were also the only two machines that lasted until the company switched to BSD-based computers in 1997.
However, storing DCRs for years was never a problem, our company had kept 20 in stock since 1990 to compensate for failing ones.
Diagnostics are really only reliable if you know how they test what they test. For example, some ram tests may pass, while others on the same exact ram might not pass. Testing methodology matters.
I think my favorite old computer diagnostic tool was the "G-er." This was literally a DB-25 with a toggle switch on it and some pins jumpered inside. What it did was print upper case G's or if you flipped the toggle switch, lower case g's. This was a quick and dirty test to see if your dot matrix printer had a stuck pin or bad pin driver. G was particularly useful as it had descenders on the lower case g. Kind of like a printer loopback plug.
Great video as always Adrian. Have you ever consider making a video of your setup? aka what software you use in the modern PC of the basement and its periferals and the various gadgets or adapters for the diferents machines you fix?
i love your content. keep up your excellent work.
The main processor in the C128 is actually a MOS 8502 ( en.wikipedia.org/wiki/MOS_Technology_8502 ). It's _almost_ the same as the MOS 6510 in a C64, but not _quite_ (much as the MOS 6510 was mostly the same as a MOS 6502). I'm curious if the C128 used that "P6" signal for anything.
It's alright Adrian, I got you covered. It is the C128D... 'D' for Derelict
Adrian, that final screen from the demo... the only thing that could possibly make sense is that the SX-64 portable was called the Executive-64 in some regions. But 96 colors? Wow, there's a long distance between a 1 and a 9 on a keyboard. That's a hell of a typo. And let's not even talk about the Apple part.
That IPA dispenser is fantastic, I need to get one.
Hi Adrian! I just ordered my first flat 128 so this video is very timely, informative and useful to me! I have the versa cart cartridge with all the diagnostic tools so I should be all set in case I need to troubleshoot any issues! I just received a 1571 drive and it seems to read a few of the floppies I have but being bought on eBay, I have no idea if they are any good or even erased!
What is the name of the donkey kong game you run, seems like the best SID tester!
Thanks for all the videos!
The keyboard adapter comes in handy for SX-64, too...even easier.
If you got the SX-keyboard cable, all it takes is a gender changer to use the C128D-Keyboard on SX64
I know, usually the SX cable is missing, but that´s a straight through, as far as I remember. So one could even get rid of the gender changer and use a standard 25P-cable with C128 KeyB. You´ll need a dremel though to make a 25-pin fit on SX
Hi I am loving your channel just wondering what do you do with all the machines that you fix and are they still useful today or are they just cool retro things to have around and save
Thanks Peter from Perth Australia
Great video. I like the journey.
The fan was going to be there but was pulled at the very last moment to save money. Bil Herd talks about it in a video that the C128DCR was done, and he moved to working on the 264 line (plus/4, C16 & C116). He said it was much later that he found out they had removed the fan. Here is a SHORT video of a photo collage of me installing a fan (Noctua 60 X 25mm) into my C128DCR on May 19, 2022 and a video of what it looks like done and the fan start up and shut down. ua-cam.com/users/shortsRgwsc672yjY?feature=share
Pitfall instead of diagnostics ROM saved my day! 🤣
anyway dude. Your'e the man, Adrian.
I had a 128 as a kid. It's true that 128 mode mostly went un-used. There was one killer feature though, 80 columns on a terminal program for calling BBSes, and word processors.
By the late 80s and into the early 90s having only 40 columns of text was a pretty big limitation. There were a few programs that could sort of fake 80 columns of text by using graphics mode instead of text mode, but the text was not very sharp, and hard to read.
So having 80 columns of sharp text was sort of huge for these two reasons. IIRC I even lent mine to a friend to use as his terminal in the mid 90s, so he could connect to the early internet, and read email, get on IRC, etc.
One thing that joystick tester doesn't seem to test is the POT X/Y operation which comes from the SID and can often be bad. Really should try some paddle tests on those ports...
I managed to get a working 128 DCR as part of a massive Commodore salvage haul several years ago and it's my pride and joy. LOVE it!
Good mod is to make a couple little dip-switches hooked to the (cuttable) pad/traces on the MB that control the drive number for the internal. I cut mine to to set it to Drive 10 as I always run everything from a Ultimate2+ Cart instead of messing around with real floppies anymore....
Missing keyboard is also a big problem with Amiga 1000's found these days. The keyboards rarely were kept around... :( And it's tough to find a replacement or even something that can be adapted to work.
The problem with the Z80 on the 128 and the CP/M Cartridge for the C64, is that the Z80 is running at the same speed as the 6510 of 1MHz, when CP/M Machines were running between 3.5 and 7MHz. The 6502 at the same clock speed, rund 4X faster than the Z80 and 8080/8088/8086 because what takes 1 to 3 clock cycles while the Z80/8080/8086/8088 uses 4 to 8 clock cycles for the same or similar machine code.
It is Commodore's mistake in running the Z80 at the same clock peed as the 6510 when they could have put in a separate clock for it.
40colums on CP/M Being bad? Again, many CP/M machines of the time has a strange 32X16 or 64X16 screen, so compared to that, 40 would be in the middle of the two.
Remember, for its time, CP/M was the leading OS for more than a decade and if it were not for a marketing mistake, would be the leading OS to this day. It is not stated but the System on the Atari ST is CP/M Based, using GEM on top of its DOS, which for Digital Research was modified version of CP/M.
The Z80 in the C128 does not use the same clock as the 6510. The Z80 has a 4Mhz clock and runs at that speed the problem is that (and some one correct me here if this is not 100% accurate) the Vic II is still running in slow mode (1mhz instead of 2) and the Vic is doing the memory refresh for the DRAM so on half of the 4Mhz Z80 cycles the Vic halts the Z80 to do it’s thing, which renders the effective speed of the Z80 to around 2Mhz, which indeed is very slow.
Hi Adrian. It may be that the cassette port loop-back connector was deliberately designed on the C128D so the old one won’t fit due to changes in the electrical specifications; it’s not just the mounting tabs (ears)! Just guessing, here.
Control ports fail when the keyboard lines are FUBAR because they share the ports on CIA 1. A well-known issue on the 64/128 is a joystick in port 1 causing phantom keypresses if wiggled.
I wonder if theres gonna be a channel in 20, 30, 40 years doing this kind of work with computers we use now. Imagine someone performing a resurrection on a threadripper or xeon they found in the trash for free.
Yes! The 8-bit dance party is always awesome to see.
I have a C128 sitting in a closet but it isn't working due to the power switch being messed up (I wouldn't be surprised if some traces were in rough shape too, as it hardly ever booted into C128 mode, but C64 mode would work fine). I have zero experience working on electronics so I have no way to repair it.
On a side note... Seeing that the C128 machines have an 80 column mode, do you think someone out there might make an 80 column version of the 8-bit dance party? It would be a lot of work, I'm sure, but that would be a pretty nice way to make sure that the 80 column mode on any C128 that you work on is functioning properly (especially if such a version let you press a key to change the colors used).
I thought the D in 128D stood for disk drive because it has a built in disk drive.