Fault finding and trying to fix the Apple ][ plus
ฝัง
- เผยแพร่เมื่อ 17 ม.ค. 2025
- Welcome to part 3 of the Apple ][ plus series. Let's start fixing stuff!
Part 1: • A viewer sent in a ver...
Part 2: • Apple ][ plus extreme ...
Part 3: This part!
Part 4: • Fixes for the Apple ][...
Part 5: • Apple ][ plus: 8304 re...
Part 6: • Apple ][ plus: VIDEX 8...
--- Video Links
The Apple II Circuit Description by W. Gayler
mirrors.apple2...
--- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/...
Jonard Tools EX-2 Chip Extractor:
amzn.to/2VazxDS
www.jonard.com...
Wiha Chip Lifter:
amzn.to/3a9ftWw
www.wihatools....
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.co...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/i...
EEVBlog 121GW Multimeter:
www.eevblog.co...
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/i...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfrei...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/i...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/i...
Heat Sinks:
www.aliexpress...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/mis...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorec...
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino
Outro Music:
Abyss by | e s c p | escp-music.ban...
Music promoted by www.free-stock...
Attribution 4.0 International (CC BY 4.0)
creativecommon...
![Fixes for the Apple ][ plus Language Card and Keyboard](http://i.ytimg.com/vi/wVUWaodwNNI/mqdefault.jpg)
![Fixes for the Apple ][ plus Language Card and Keyboard](/img/tr.png)
![Repairing an Apple Disk ][ drive with multiple faults](http://i.ytimg.com/vi/e1_aI88Xr98/mqdefault.jpg)
why is it, that whenever Adrian attempts a well thought out bodge (like his triple stack), when he tries it out and it works, the genuine joy in his voice, makes me sit here at home in the UK, smiling to myself. To be honest, I don't know why he's surprised that it works, the guy is a genius in my eyes.
he's got a good mix of technical knowledge and humbleness, I wish more tech youtubers were like that instead of being arrogant with their ability.
That is an awesome bodge!
Great idea to shift the IC up one row!
Well put. The trick is having a diagnostic mindset (the ability to hunt down and isolate separate issues while keeping a clear head) and to be well organized at the same time. Adrian is very good at both and he's also good at presenting/transfering his findings to his audience in a down to earth way which takes enthousiasm and a certain 'hunger' to hunt down bugs/defects, which he clearly has. Always a treat to watch his videos! They always hit close to home for me as he constantly reminds me of the way I do things and I have to say and I learned a lot by watching them. Big thumbs up for this guy! Keep on making excellent content 👍
SRAM and (octal) buss transceivers... As I think back over my decades of repairing logic boards, these two components seem to have the highest percentile of failure rate out of all other integrated circuits. Nice troubleshoot and VERY creative solution in "reconfiguring" the I/O pins of the 74LS245 Adrian. Has anyone ever told you that you have a propensity for teaching? You would make an incredibly good electronics teacher! Cheers, Fred
What a great feeling it is when you revive something like this. Then what a sinking feeling when months later it develops another fault, as vintage electronics seem to do. But then another rush of achievement in reviving it yet again.
This channel makes me happy.
Showing the schematics and where you're probing is pretty nice!
Watching this is like watching a detective TV show and it breaks off as things get interesting!! Sigh - look forward to the next exciting episode next week!!!
After he finally fixes it, he should say "oh, wait... What's that?"... followed by "The End???"
I love these old computers! I'm 24 (so way after when these computers would have been in schools) and thoroughly interested in computing history.
I can definitely recommend the Apple IIe for you (excuse my pushiness if you already have what you need). They aren't crazy expensive. All you need is the main unit and an audio cable. You can use websites on your phone to stream the data (as audio) to the computer to load programs. Additionally, it connects to any television that accepts a composite input. And if something goes wrong, you have this channel for a reference!
@@SixOThree Yup, I have a number of retro computers and would agree with your suggestion as well. It's not my favorite retro computer, but it's definitely the one that offers the most tinkering ability as well as an abundance of software. It's also relatively easy to find.
@@SixOThree Thanks, I'm not sure if they will be particularly easy to find in the UK but I'll certainly keep an eye out. My current goal is either a BBC Micro or a C64 and appropriate CRT monitor.
im 11
@@LoopyLucy95 hi im 11
Loving this little series, I just marvel at the knowledge and the thought process, rather than a typical "lets change everything" you actually workout the way the machine works. I know that should be the standard way but you see so many people just bulk replacing chips. Looks like another machine is getting the thumbs up Adrian so you got one as well. Greetings from the cold old UK and keep yourself safe, Paul.
I like how you show the bone-headed mistakes. It makes me feel better about doing them myself when I am messing with this old hardware.
One of the fun things about repairing is it's like going for a walk somewhere new, yeah you can get lost on the way, but end up learning as you go and finding your way back eventually... :)
You don't have a patron or TH-cam subscription service. You make some of the best content on the net. I'd gladly give you a couple of bucks every month for all you do.
Thanks for the feedback. I'm think of finally creating an account there.
I am a Sinclair ZX80, ZX81, ZX Spectrum user, never used or owned an Apple PC and never will, but Adrian’s skill and enthusiasm makes them the most interesting repairs on TH-cam, Thank you Adrian, looking forward to the next one and many more.
Most of the time I have no idea what you are doing but the way you follow the board around is very logical as you do repairing a computer. Thanks Adrian
Impressive stuff Adrian. When you found the dead chip and you didn't have any of them I think most people would give up. To work out and find those chips that stacked together like that would do the job of the bad chip was really impressive and shows your dedication to getting these old and rare machines working again. It was great to see it boot up again after that fix. Great stuff.
Wow, great troubleshooting!
Glad you got it working!!
I appreciate that you show us your mistakes so we can learn from them!
That pin header in the video area was for an RF Modulator add-on.
Because Composite RCA jacks on TV's were uncommon in 1977.
*Sup* *'R'* *Mod* *II* has a wiki page.
Everytime I hear the intro I shout 'JAM ALERT' because that tune is so gooooooooooooooooood!
I love the Sherlock Holmes adventure of finding the mysterious fault and you are really pleasant to listen to as you tell the story well done Adrian I’ve watched almost all your posts .. cheers from Australia
The way you diagnose problems like this on these old computers is just fascinating.
Wow, you track down the these interesting faults and then manage to come up with a creative resourceful way to fix them - makes a great video!
This is some humongous high level troubleshooting! Great job!
The 2+ is the first computer my family had & was my introduction to computers. Really enjoying this series.
Adrian, you are so passionate, I really love to see you fix computers. You are always an inspiration for me and my retro hobby! Best regards from Germany!
I never understand all the gobbledygook you say but I do love your videos especially when you finally fix the item you're repairing 👍🏻.
I used the trick of sharply pulling up several times(basically the opposite of a quick key press)on each key on the keyboard of my II+ and it's worked for years since. Nearly half of my keys didn't work prior to doing this.
The 4-pin header near the video jack is not for 80-column cards, but rather for an RF modulator for connecting the computer to a TV. The Sup'R'Mod was the de facto standard RF modulator back in the day.
Let's get right to it!
"Don't worry, there are more faults!" :D
yayyyyyyyyyyyyyyy
This is fast becoming one of my most favourite channels.
I'm always waiting for the "Oh-ho! Look at that!" moment. Thank you for another awesome video.
Some old Acorn computers suffer the same keyboard problem after long periods of disuse, particularly the Acorn Electron and the BBC Master 128. My fix has always been to hammer the keys repeatedly until they start working, which sometimes takes hundreds of keypresses. There's also a way to desolder a switch, unscrew the pins from underneath, clean them up and reassemble, but I don't know if the Apple II uses the same switches. They certainly sound a lot like the keyboard on the Electron.
Awesome video! Love seeing full repair videos. Takes me back to the 80s (and 70s). Keep it coming!
I totally share your joy, Hey look at that!! It’s working, that got me hooked 40 odd years ago on electronics and it still does. Excellent work my good man, Permission to engage ‘Smug Mode’ ,,,, Red Dwarf Quote :)
I love watching this...memories...I built my own Apple ][+ clone back in the 1980s, and it brings back memories of both debugging my own MB and helping other people in the Ottawa Apple community, or the 6502 Users Group as it was called. True, we did have Commadore people too, but I didn't interact with them...
It's always the tristate buffer. Even when it isn't it is.
What about the case where it both is and isn't?
@@r.l.royalljr.3905 Yes.
@@r.l.royalljr.3905 schrodinger's tristate buffer.
@@retroguy74 Oh no.
Now that’s creative the way you put your own style on it!
8:24 that's an LCD panel not getting the right signal and the control chips not driving the pixels
It's got an afterimage of your windows start bar on it
A long time ago, I bough old computer boards with a lot of TTL chips. The sockets were Texas Instrument sockets and when I tried to reuse these sockets in my projects, they weren't reliable. Plus the use of rosin flux caused some problems with the socket. When using flux remover, it left a film of rosin on the socket pins so that circuits no longer worked.
The best sockets are those dual leaf sockets.
Nice analysis of the signals and reasoning to find the error(s). Looking forward to part 4!
Excellent work and that book is a must for Apple II repairs. I love my copy! Nice to know about the piggyback option.
I have a very different approach to replacing parts. Rather than badge something to support a different chip, I would order the right part, or failing that, send of an order to OSH Park for an adaptor PCB with a surface mount IC.
ADB comes up with a Frankenstein fix in an hour, I come up with something prettier... in 4 days to three weeks. Haha.
This might explain why I have piles of half-finished projects on my workbench.
Yeah, I think it is wise to do the bodge just so he can prove the part is bad! Otherwise you have to put it aside and wait for parts to come, then try to remember where you left off when you finally get back to it! Plus, he can enjoy the fixed computer now while he waits for the replacement part!
Adrian, you continue to amaze me you wizard! Remarkable work.
Really nice diagnostic work Adrian. Long live the Apple ][ !
Hey Adrian, I just used your desoldering method to replace some dips with sockets on a 1982 fruit machine. Thanks for the tips. 👍👍
Ah crap! The last video was a real cliff hanger on the end. As is this one!
Loved it nonetheless! 😊
Thank you for all of your time and work you put into this and your other videos.. great job
Congrats Adrian. A pat on the back for you from Australia
interesting fixes you had for the apple. Much better looking at a circuit diagram as you are explaining what is happening. great to see you work.
Very nice! I had a Franklin Ace that was in a house fire, was able to restore it and put in a jameco supply.
Awesome troubleshooting process! Thank you for the instructions!
Another well done diagnostics and fix session. Good job!
32:56 it looks like the crimped RCA ground ring is still spinning in the frame in this shot, I think you got good solder bonding on the frame but not on the sleeve/ring part. Might want to go back and touch that up, otherwise your flaky composite output problems might return!
at 4:47 he says "that's a warm chip" (8304) that should have been the first clue..a can of component cooler might be helpful (back in the old days ..now an infrared camera would be better to spot hot chips) ...there is really no reason for a Transceiver to run hot unless something is wrong...for the triple stack..very creative..myself i would have just bent the 3 misaligned pins up (outside of socket) and run wire wrap wire from each pin to the mother board and install chip in the socket one pin down..this would look more professional and cleaner..I worked for Tandy back in the 1980's and we had to do this sometimes to make factory mods.....granted to replace the chip you would need to unsolder the 3 wires and install a new chip and solder the wires..putting original in would just be cut the 3 wires off mother board...
As soon as he said warm chip, I thought that's the bad one :) No good content in that though. We all would have skipped this vid as 'too easy' Had to have the satisfaction of full diagnosis. It makes me want to pull out my bad 2e board and get stuck into it
@@tenmillionvolts good point..I also wanted to add to all beginner techs out there..if you do not have an infrared camera and cannot find component cooler..you can also use a can of compressed air "Computer Duster" just invert the can and spray..
This channel totally makes my Wednesday and Saturday :)
Excellent detective work tracking down that motherboard chip. I don't think I would have gotten it.
So, in the meantime I'll wait for your midweek video. Every Wensday and Saturday I am waiting for TH-cam to tell me, your new video is online. The differenc to other retro computing channels is, you show the trouble shooting and tell us every mistake you had done. That is a cool way to lern diagnose one of those old 8-Bit computers!
That really is one clean motherboard! What a wonderful gift.
He cleaned it, It was dirty when he did get it.
Tho, the gift is wonderful of course.
Woohoo "APPLE ][" good job Adrian
Another great video, Adrian. Illustrating the chip pinouts as you test them is a really nice touch, makes it super easy to follow.
Just one tiny issue... if you watch 32:56 - 32:58, there appears to be a minute amount of movement in the RCA jack. It's hard to pick up at regular speed; it become quite obvious at 0.25x. Because the movement is so subtle, it probably wasn't obvious at the time of filming (as well as being easy enough to miss during editing).
The IC leg straightener is not in the description but it helped me to find that chip lifter you use at a reasonable price.
Ahh, this fix was such an adventure, I'm so happy seeing it working.
This is much better than the long mail videos... Seriously, no one want to hear about candy or how many you've already ate...
It made me really happy when the adaptor worked.
Love the intro music. Reminds me of a very young me enjoying playing c64 games..
Wow, I would have given up long before you. Great job debugging and fixing that bad chip!
As you were explaining the down shift with the 74LS245 & 8304, i was already visualising a stack method before you revealed... weird.
@Adrian's Digital Basement yep Brendon i love it how he explain it
but i did the same it is saterday so why not make some piggypack to spare delivery time
you can also buy it for $5 www.reactivemicro.com/product/8304/
but that's no fun if you know how its works why not using a replacement
Another fun repair =D Looking forward to part 4!
Nice repair. Excellent part substitution.
im your Malaysian view, i like how u fixing the old computer, this is really fun project yo XD
cant wait for the part 4 video
Great video! Nitpick though that stack of floppies you had on the bench was sooooo intriguing I was trying to see the label of the top one for a good 2/3 min lol :)
Yesss! You just invented the 2020 version of the 8304 IC ! I intensely followed this video like a thriller movie 😅 and i guess that final solution was you last card to play on this issue ! Cool fixing and cool computer, i'm trying to find an Apple ][ too but i'ts pretty hard (and expensive). You should have said "Stay hangry, stay foolish" instead of healthy and save at the final 🤣
A 74F545 is a pin compatible replacement for an 8304
Ah, that explains why it exists. I never understood the point of the 545.
Good video. Next time you want to solder the phono socket first run a file along the grove a few dozen times, maybe even rough it up with some sandpaper. The solder did not flow well on that repair.
yep sill rotates
Very cool.
These are the type of mods I like.
Taking the modern or easier to find equivalent and creating a non destructive method for making it work.
Adrian === Love your videos. Great job. Thanks.
I love the premise of your channel
My first computer ever was an apple 2 plus. It seems like a hundred years ago. Being that it was almost 40 years ago I took a class in basic programming at 10 going on 11, I wonder if I could remember how to do a basic program
Well done for getting it running. The 8304 (at least the Am version) is capable of +/- 48 mA output drive capability. The 74ls245 (TI) can only do -15 / +24 mA. I suspect this would only be a problem if you have a lot of expansion boards plugged in.
Interesting -- I had the machine fully loaded with cards (except for slot 5 and 7) and it seems to work great in this configuration. I wonder if most Apple II cards don't use their own 245s to go high Z on the bus like most ISA cards do....
@@adriansdigitalbasement Even in the high Z state, the devices will draw some current, especially when presented with a logic "0". The keyword here is "fanout" - how many inputs you can drive with a single output. It is easy to exceed it on data buses if you aren't careful, which is one of the reasons people add buffers. You can see if the driver is struggling with a 'scope, as the low state will be getting close to the threshold - about 0.4 V.
I hit the thumb before watching, I knew it would be great, and I was right ! :)
Great fix, especially the custom 8304 adapter!
In terms of diagnosing faulty chips, have you considered using a DMM in diode mode to test each pin with the positive probe connected to GND?
Love the fault finding well done, really good of you to show the pins you are measuring .
@28:00
Is the 8304 a 245 rotated 180 degrees with vcc/gnd swapped?
I made an adapter for an LS244 when my 8T28 (or what was it) bus transceiver went up in smoke, because even though my local electronics store (which now only sells computers and computer parts, RIP) had 8T28s in stock (new old ones), they were insanely expensive like 20 bucks a pop or something.
EDIT: The machine I'm talking about is a 1980 bootleg Apple ][ that has some differences to the one shown in this video
Posting this while still watching, currently at 19:23 when he just removed the memory chips to figure out why D0 is being held low. He mentioned the third chip not being installed because that's where the Language Card plugs into, and that triggered an alarm bell inside my head. If no language card is installed, then that socket needs to be populated with a RAM chip. Since that socket is empty, that could be why D0 is being held low. (I'll edit this comment later if needed as I continue watching.)
EDIT: Ok, it wasn't the cause of D0 being low. However, it still is true that the white RAM socket needs to be populated if no Language Card is installed, so further testing down the line might have issues with that socket being empty.
Adrian... You are aptly....did great job Sir ✌️✌️🇧🇭 thank you very much much indeed..
You have channeled your inner Woz!
Deoxit that Socket! - As always 😀
YES
I have that same T-shirt. Great fix, BTW, and well explained.
I always wonder if these computers worked the last time they were used and it was the storage that killed them or if they died while in operation.
Excellent work Adrian! 😄👍
Another awesome video done! I could tell your excitement when you got it worked. Well done! How did you find out that the 74LS245 was compatible with the 8304?
32:58 Still twisted a little bit :) Maybe you have to crimp it with pliers.
saw that too!
Really wish you did more pcb designing.
Isn't the leftmost ROM the character generator? During the video phase, if text mode is selected, the ROM is addressed by the video address generator plus the contents of screen RAM. Chip select is low, and the output of the ROM goes to the video shift register. So you would see activity on that ROM.
Great video once again Adrian. Now to completely ask something off topic. Above your work bench is a small display that appears to have different Atari game related displays popping up. Very interesting. I'm sure in a past video you addressed that little gem, but for the life of me I don't recall you mentioning it and yes I watch most of your releases. So 'inquiring minds' (or at least one of them) wants to know just what that is? Thanks in advance.
Great analysis and troubleshooting. I learn a lot :)
Thank you sir! Another great video, as always!
Love your video's could you please tell me where you bought the IC sockets and the screwdriver pray tool you use to remove the iC's with,thanks
I have the retrotink 2x pro (same one as you I think). It's never done that.
@30:17 - even if the direction signal was inverted you could have just turned the chip around :)
Yeah would have just been more wiring work :-)
Nice Frankenchip! It's alive!!!
Could all those keys be on one line? could it be just one broken column or row in the keyboard matrix?
Tektronix had lots of issues with TI IC sockets in the 70s and 80s, the suspect ones contact the edges of the pins rather than the face of the pins; the only long term solution is to replace them.
It's the worst kind of problem too