Apple II+ clone repair: I thought this would be easy... I was wrong

Рет қаралды 120,341

10 ай бұрын

In the early 80s, the Apple II had was selling well but it was expensive. This is where foreign companies stepped in and started making clones. These machines were much cheaper but also illegal due to them using copied ROMs.
Here we have one of these clones but this machine is broken, very broken. So let's try to get it working.
Small correction: It turns out Franklin did not have a clean-room ROM, and were eventually found to be infringing. There isn't much detail about why Franklin was able to sell computers until 1988. See the pinned comment for more.
Part 0: • 0068 This computer is ... (SMMC video featuring this computer)
Part 1: This part!
Part 2: • Apple II+ clone repair...
-- Links
News report on these illegal clone computers:
• 1985 New Tech Times on...
Scan of schematics and photos of the clone PCB:
archive.org/details/apple-ii-...
Adrian's Digital Basement Merch store:
my-store-c82bd2-2.creator-spr...
Adrian's Digital Basement ][ (Second Channel)
/ @adriansdigitalbasement2
Support the channel on Patreon:
/ adriansdigitalbasement
-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
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.com/products/digi...
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.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/itm/1-2-5-10PCS-...
Heat Sinks:
www.aliexpress.com/item/32537...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino

Пікірлер: 377

@adriansdigitalbasement 10 ай бұрын

Small correction: It turns out Franklin did not have a clean-room ROM, and were eventually found to be infringing. I can't find exact specifics about this as even Wikipedia lacks citations, but this seems to be the general consensus. Even this article specifically about the case lacks detail: en.wikipedia.org/wiki/Apple_Computer,_Inc._v._Franklin_Computer_Corp. It talks about how Apple "won" in 1983 but Franklin continued to sell its very compatible Franklin Ace line until 1988, when "Apple was able to force Franklin to withdraw its clones by 1988." That doesn't exactly make sense to me -- so If anyone can dig up more detail about how Franklin continued to sell large numbers of machines with supposedly infringing code, I'd love to know.

@Slim_Chiply 10 ай бұрын

I never really saw a Franklin in the wild. I remember there was a shop by me that sold the Pineapple or something similar.

@dru6809 10 ай бұрын

The case was famous. They had a guy read the fuses of a ROM with a microscope in order to show that this was really text and should fall under copyright law.

@fnjesusfreak 10 ай бұрын

The answer, if MAME is anything to go by, is that they replaced the infringing ROM with a cleanroom one for their later models.

@rlgrlg-oh6cc 10 ай бұрын

At the time Franklin started making their computer, there was a legal precedent for code that was in memory chips not being subject to copyright law. I believe the original case involved a pinball machine. This is why Franklin copied the ROMs and won the first few rounds against Apple. Eventually, the courts figured out that of course the code should be protected, no matter what form it took. Franklin at that point was forced to change its EPROMs, They rewrote the routines, keeping only the entry points which an app would call. Unfortunately, since Apple had published the entire code, some programs would jump into the middle of a routine if they only wanted to do the last part of its function. This kind of thing made it impossible to be 100% compatible without copying all of the code in the EPROMs. Luckily, a lot of programs only called the entry points and ran fine on the later Franklin machines.

@derekchristenson5711 8 ай бұрын

I know it's just anecdotal, but my aunt and uncle had a Franklin Ace 1000 back in the day, and I specifically remember them saying that Apple successfully sued Franklin after proving that the ROM's were 100% identical to Apple's, including the name Apple itself appearing in the code. I also remember much more recently someone (not the comment below, but someone on Facebook) saying that Franklin and other clone dealers switched to selling Apple ROM kits as "spare parts", with a nudge and a wink about how to achieve 100% compatibility. I was just a kid in the 80's, though, so I never dealt with any of this more directly than using my aunt and uncle's Franklin, since we didn't have a computer. It seems like *someone* must have hardcopy documentation about the exact chain of events, though.

@Anachronda 10 ай бұрын

back in the day, you could buy bare boards for apple and ibm clones from ads in the back of magazines. that's how some engineers at a place i worked acquired machines; buying a computer required approvals, but buying parts was just buying parts.

@SonicBoone56 10 ай бұрын

If only modern PCBs weren't as complicated. Imagine buying the parts for a full machine via a loophole.

@Loki- 10 ай бұрын

@@SonicBoone56would you please elaborate? I don't understand the difference. As in older PCs had the system burnt into the boards?

@LeoA2600 10 ай бұрын

@@Loki- Loki, modern computer components like motherboards aren't user serviceable. They're all surface mounted parts, microscopic traces, many layered PCB's, etc. You're only buying major components like graphics cards and connecting them together when you "build" a computer today and when you "repair" one, you're just swapping out one of these major components. In the Apple II days the motherboard was simple and as seen on this channel, easily user serviceable with fairly basic skills and tools. People could buy a board and source all the components to solder on it and assemble their own, which people did back in the day (and people do today when they buy something like a modern replacement C64 board for an example and populate it with all the necessary parts).

@CATech1138 10 ай бұрын

yeah double sided boards compared to modern 8 layer stuff....yeah copy that

@michaelburns8073 10 ай бұрын

This was exactly how my Dad and I built our ][+ clone. I actually had started wire-wrapping one -- my dad worked at a famous research facility where they had an Apple CIG (Computer Interest Group), and they had a wirewrap board with a large manual of wire-wrap co-ordinates. I would come home from school and start wire-wrapping, and my dad was supposed to check my work -- but he soon tired of that, and then was able to a clone board, and those guys troubleshooted it during lunch hours. I still have it, it's got a few cool set of hacks. I need to pull it out of storage and check and see if it works. I did this some time ago and it was still working.

@davidw.2467 10 ай бұрын

When I was studying in the University I had a classmate from Taiwan who import these Apple 2 clones from Taiwan and sell them in campus. How he did it was the motherboards and chassis were imported separately, and there were no ROMs on the motherboards, which made them legal since they were just parts. Once the parts were received, he then programmed the EPROMs and assembled them into full units. It was so profitable that he eventually dropped out of school and went on setting up his own business selling Apple and PC clones.

@idahobob 10 ай бұрын

Here's an old trick I've done to find shorts like that on a board. Put a power supply though a small resistor on the two shorted lines. (5V and a 100 ohm is a good start.) Now probe voltages across those two lines... when the voltage difference is the smallest, you're at the short! As a VERY LAST MEASURE, On boards that were quite frustrating, and had put enough time into them that "it just didn't matter any more" and "zapped" the problem with high current.. would blow the short... or sometimes the trace near the short. I've also used this in car wiring, also, to find a short to ground in a RV on the interrior lighting. (found a "shiner" on the power wire, in a conduit.) Used 12V and a turn signal bulb for current limited voltage there.

@retroobsession7519 10 ай бұрын

I lived in Hong Kong in the mid 1980s. There were a tremendous number of Apple II clones as well as clones of all the peripheral cards. There was a 3 story shopping mall in the New Territories that had 100s of shops selling Apple II clones and copied software. The entire shopping mall was devoted to clone computers and software. Needless to say, I shopped there often.

@jrnovosel 10 ай бұрын

Dave of eevblog has a method he uses with a high precision voltmeter to measure resistance and triangulate on the short. You could also pull all of the chips that touch those lines and apply 5V across and use a FLIR to find the hot spot.

@markcummings150 10 ай бұрын

Another option is to try an ESR meter which typically measure down to 0.01 ohms and they usually have a button to zero out the leads. This would be better than burning out a track with 5V power and you wouldn’t need to remove all the chips to test for the short.

@Chrisa850 10 ай бұрын

This looks like a copy of an early generation Unitron (Taiwan) board. The case and keyboard look very much like those used by the Unitron branded computers built in Brazil. There are additional half moon/bow tie jumpers below the EPROMS (and a thru hole jumper above the LS139 at F2) to convert the board from 6 x 2716 to 3 x 2732 installed in F0/D0/E0. We used to find these PCBs in almost every electronics shop in the area. I built and repaired dozens of these. Most people could never get the oscillator running reliably, and often had to pad the oscillator with an added 50pF trimmer at location A1.

@Slim_Chiply 10 ай бұрын

This video is about 40 years too late to help troubleshoot the Apple clone I tried to make in the early 80s. I could solder and follow simple schematics, but without any real troubleshooting tools, it was way too difficult. I finally threw in the towel. It may have been this very same board.

@scottgfx 10 ай бұрын

I was kind-of wondering if this computer was a hobbyist's machine that never functioned. I was also wondering if Apple was seeding boards into the community that had shorts just to keep people from building clones. Perhaps a little too Machiavellian.

@haweater1555 10 ай бұрын

I would suspect that A LOT of those hobbiest bare-board builds were never working nor completed and just stayed in a basement shelf for decades.

@Slim_Chiply 10 ай бұрын

@@haweater1555 I'm sure I wasn't the only one who ran into problems trying to build one. My brother was more of an electronics wiz than I. Neither of us could get it going. We didn't have anywhere near the same troubleshooting tools that Adrian has. As well as the knowledge, I might add.

@tommythorn 10 ай бұрын

Oh that resonates so hard; I tried to build a floppy disk controller for my Nascom 2 and it worked just extremely briefly, but not having access to a scope it was impossible to debug and I didn’t touch hardware for many decades. Today I wish I had tried harder to find someone to help.

@five-toedslothbear4051 10 ай бұрын

45:58 When you say the expansion connector is not the problem, my experience as a diagnostician is that a lot of times it turns out to be the thing you thought it couldn’t be. My Spidey sense is tingling, and I would probably get a magnifier and a high-powered light, and make sure that there is nothing conductive that got pushed down into one of the expansion connectors. I can just see a little bit of material from an edge connector flaking off and getting down in there.

@Chrisa850 10 ай бұрын

With A3 and D2 being almost directly across from each other on the peripheral I/O connectors, that would actually be one of the first places I would look. Could be a damaged connector, soldering error, or even a board etching issue .

@TonyHamlyn 10 ай бұрын

Could be a leg of a component fell into one of the expansion connectors, and as was said, when Adrian probed both the address and data lines it looked like he did it on the back of the expansion connector and they did look opposite to each other.

@scottlarson1548 10 ай бұрын

The 13 year old in me loves the idea of buying a clone Apple PC board, spending months buying the parts from Jameco and soldering them onto the board, and then one day going to a friend's house to illegally copy the ROMs in his Apple II.

@typedrat 10 ай бұрын

I'm really sad that I missed the Wild West era of computing... although I've still managed to work on stuff that would make Apple mad at me all the same. 😂

@kennethflorek8532 10 ай бұрын

Jameco! First "computer" I ever had (because I could afford it) was a kit called a Jolt I bought from them. A Fairchild F8, second sourced by Mostek (of 6502 fame), was the computer chip. 1K RAM, 1K ROM. Jolt was a closeout, at a fraction of the price, after the product flopped, and the company that made them evaporated.

@scottlarson1548 10 ай бұрын

@@kennethflorek8532 I ordered tons of stuff from Jameco out of Popular Electronics. I remember buying sixteen 2114 static RAM chips at *five dollars each* to get another 8K. It was the biggest investment I had made since buying the computer.

@GothPanda 10 ай бұрын

A tip that might help in situations where you have a large set of things that might be causing a problem: instead of checking the chips one at a time for an offender, you might be able to check a half at a time. Remove half of the chips connected, test. If the issue persists, put them back, and remove the other half. That'll either rule out everything or narrow it down to half the chips. Then, repeat splitting the suspect group in half again. Instead of having to test each item one at a time, it becomes a power of two. Uses math to help rule things out quicker.

@knghtbrd 10 ай бұрын

Binary search to find a binary problem. 😁

@barcodenosebleed5485 10 ай бұрын

Kinda like a physical merge sort...

@pragmax 10 ай бұрын

Exactly. This is called a "binary search" and works for a lot of search tasks. It's a massive time-saver.

@pedro_8240 10 ай бұрын

Unless you have two failed chips, one in each half.

@gmirwin 10 ай бұрын

@@pedro_8240 then you divide it in half a different way.

@marcelosantos8484 10 ай бұрын

19:20 - Using arrows to pinpoint what section on schematics Adrian was measuring is AWESOME!

@herbertsusmann986 10 ай бұрын

Look for mashed contacts on the expansion slots. If a board was put in wrong it could have mashed the socket contact down and maybe is now shorting to something it is not supposed to be touching.

@piconano 10 ай бұрын

There was a store in Toronto called "Parts Galore". They sold everything you needed to build your own.

@electronash 10 ай бұрын

50:20 Address line A3 is on cart slot pin 5. Data line D2 is on cart slot pin 47, which is *almost* directly opposite. I would check all of the cart slot connectors, in case a pin is bent. Or maybe there is something conductive sitting in the bottom of one of the connector slots? (like a piece of wire, or solder blob). It's also quite possible somebody was messing with the board before, and put the wrong TTL chip into the wrong socket.

@MrPGT 10 ай бұрын

I was going to suggest a possible short due to touching connector fingers in the cart slot, too.

@baghdadiabdellatif1581 10 ай бұрын

I think Adrian intentionaly put the solder blob and will say that it fell when he changed the transistor😂

@GodmanchesterGoblin 10 ай бұрын

I haven't shouted at the TV so much in ages... 🤣 Badly defined logic levels where the line settles quickly to an intermediate voltage and stays there until the next transition (as per the weird scope trace) is almost always a short to another signal. You effectively had four steady signal levels on that trace, depending on which of the signals was high or low. Finding the fault is a case of either visual examination and / or using a meter on a low ohms range wherever those two signals are close together on a chip or on the board and looking for the reading that's closest to zero ohms. I first learned this trick back in the late 1970's debugging memory cards with lots of RAM chips. The fault is unlikely to be a chip - most likely a solder splash, or a fine copper whisker caused by a bad etch of the PCB. Back in the day, not all PCBs were tested for shorts between traces before assembly.

@Sashazur 10 ай бұрын

A splash or a whisker sounds like the kind of problem that would be there from day 1, but presumably this system was working before it went into a few decades of storage.

@GodmanchesterGoblin 10 ай бұрын

@Sashazur There is a phenomenon known as "tin whiskers". These can grow over time, and were sometimes a problem in older electronics, even forming inside components after some years. And we don't know if this system was ever fully working, but I would also suspect that it was.

@jdmcs 10 ай бұрын

The Franklin Ace 1000 was actually an illegal clone. It was allowed to stay on the market while Apple Computer, Inc. v. Franklin Computer Corp. was on appeal, partly because the initial court rulings were that compiled code could not be copyrighted. (The Franklin Ace 500 and the Franklin Ace 2000 used cleanroom-implemented ROMs. I believe this was a result of other court rulings that compiled code could be copyrighted.) Eventually, Franklin and Apple settled, with Franklin being barred from ever selling computers (including PC compatibles) as part of the settlement. One way other Apple clones got around the import bans is that they were imported without ROMs, and ROMs were either installed by the seller or end user.

@SonicBoone56 10 ай бұрын

I thought Apple eventually bought Franklin as their educational division.

@jaybutler 10 ай бұрын

@@SonicBoone56 No. Franklin actually morphed into a different company. They went into electronic publishing and made some devices associated with that. They made things like pocket spellers and pocket Bibles. The company definitely existed into the early 2000's and may still exist in some form today.

@haweater1555 10 ай бұрын

And the instructions for ROMless clones said to go find an authorized Apple dealer that will sell you the genuine ROM as a replacement part (before Apple caught on and jacked the price up for this chip to reflect the intellectual property contained inside).

@CaptainRon1913 9 ай бұрын

@@haweater1555 You didn't need to buy them. Could just copy them on a eprom reader/writer. i.imgur.com/RDxFJeQ.jpg

@eddies 10 ай бұрын

Here is how you quickly find a short like the A3 to D2. Pick a ROM and take a resistance reading. It won't be 0 ohms, but something like 0.6 ohms. Then keep one probe on D2 and find A3 on another chip and take another resistance reading. If the resistance reading is higher, as in 0.7 ohms, you got physically farther from the short. If it's 0.5 ohms, you got closer. Keep going until you get the lowest number you can. Then keep that end of the meter lead on D2 on the chip with the lowest resistance number, then start over with A3. Move the meter lead to A3 on other chips, take a ohm reading, and find the point you got the lowest reading. It will often be near your D2 point. At then point you have the lowest ohm reading, is really close to your short. If you break up the board into a search grid, you can speed up the process more. If you get a higher ohm reading on a chip on the upper left of the PCB then the lower right, then focus on the lower right. That said, before doing the above, I check the user damageable things first. Like the card connectors. If the two shorted pins are near each other on a connector or cable, then they could have been damaged or shorted.

@cURLybOi 10 ай бұрын

adrian: "this could be a ROM problem" my brain: "pROMblem, hehe hehe he"

@rager1969 10 ай бұрын

I'm thoroughly enjoying this video and writing this around the 32 minute mark when you say the chips are a hodge podge. It occurs to me that this system may not have been built in a factory, but by an end user (or the seller) using one of those bare PCBs and grabbing whatever chips they could find. Back then, there may have been local electronic shops that didn't have large lots of parts, and maybe the builder had to go to multiple physical or mail order shops to get what they needed and/or whatever they had on hand.

@CaptainRon1913 9 ай бұрын

Yep, and those memory chips used to cost $5 dollars each back in the day.

@Omarshmallow 10 ай бұрын

I've never used an Apple II (I grew up a C64 guy) and I don't understand half of what you're saying, but these videos are truly fascinating to me. Watching your troubleshooting process and enthusiasm for older tech is very inspiring. Keep up the good work!

@zbradbell 10 ай бұрын

I wouldn't be surprised if this was bought as a kit, and the builder didn't have the skills to successfully get it working

@EnthusiastPC 10 ай бұрын

Lovely throwback for me, I used to watch (and try to help) my father way back in 1981 repairing these. He was an electrical engineer. Thanks for these videos 😁

@BobMonsen 10 ай бұрын

Thank you for changing the color of the oscilloscope trace! Colorblind folks everywhere salute you!

@winstonsmith478 10 ай бұрын

Like the "Lazy Susan" to rotate items while recording.

@c1ph3rpunk 10 ай бұрын

Poor Susan, why does she get such a bad rap.

@gregsmith9183 10 ай бұрын

One of My first Apple computer was a Taiwanese Apple II clone clone called the Unitron u2200. Basically a desktop case with detachable keyboard/speaker. With 64k ram, 6 expansion slots and 6502 & Z80 CPU. I'm sure they were legal to sell as we had these in my high school computer labs here in Australia before they were sold off and replaced with twin disc drive MAC SE computers.

@tommythorn 10 ай бұрын

Thanks for leaving IN the mistakes. I enjoy watching the process and learn a bunch of good techniques. Like I wouldn’t have considered that heating the transistor would bring it back to life. I used what I learned to bring my Nascom 2 back to life. Turns out I must have removed a bodge wire I installed 40 years ago, but tracing the signals methodically lead me right to a missing connection.

@atarimex2643 10 ай бұрын

A Franklin was the first computer I ever used. This was at a “intro to computing” summer camp in 1984. Great memories playing Karateka.

@piconano 10 ай бұрын

A Huntron tracker or curve tracer can identify bad output drivers of an IC without power applied to the IC. You can also disconnect the clock, power up the board and use a logic pulser and logic probe to test logic ICs. It a pain and time consuming, but doable.

@wcg66 4 ай бұрын

I had an Apple II clone bought in the mid 80s. I actually bought it from a shop teacher at our school. I’m not sure that would fly today! It worked for years and I used through out university. I typed my these in Wordstar on the CPM card and print pad on my Epson MX80.

@kiwischolz9811 10 ай бұрын

Back in the days when Apple made the most expandable machines... And today you often can't even change the harddisks or add more memory.

@KAPTKipper 10 ай бұрын

and repairable.

@craigthepony6259 10 ай бұрын

You used an unapproved apple screw, your operating system is disabled.

@TheSulross 10 ай бұрын

and they even take away ports (e.g., audio out port) and have a penchant for their own proprietary connectors where they could easily go with industry standard choices (e.g., the power connector)

@oofingberg 10 ай бұрын

@@TheSulrossmagsafe is the best thing apple has ever done (the MacBook one. The iPhone magsafe is stupid)

@williamsquires3070 10 ай бұрын

Yeah, we need a new Steve Wozniak. 😊

@dnorman2134 10 ай бұрын

Back in '80 or '81, my father and went to various stores and bought all the parts needed to assemble a clone at a fraction of the cost of an Apple. it has the same case, keyboard doesn't have short cut functions. Motherboard had a Unitron branding on it if i recall. it was very close to the board you have there. It took us about 2 weeks to complete the soldering with only a couple hours a day for one of us to work on it. We knew people with equipment to burn eproms back then, so, we had copies of the originals, we also had the modified beep tone and banner, which I'm sure are still in it. I loved the Apple ][ era. (also had a TRS-80 Model 1 L2 with floppies and a modem. my father would use it to connect to the main frame at work to look at issues. i would use it to play text based games and Adventure!. )

@tigheklory 10 ай бұрын

It would be so awesome if classic computers schematics were translated into open board view. Have you ever seen Louis Rossman use the software he can click on any point in a board view and see where the pins go and even what should be on that pin. Hope someone sends you a Coleco Adam in the near future!

@DavePoo2 10 ай бұрын

Amiga PCB Explorer does this for the Amigas

@Colin_Ames 10 ай бұрын

It’s always fun watching you go step by step through the diagnostic procedure. Looking forward to the next episode.

@hisham_hm 10 ай бұрын

Amazingly, my first computer was a clone of this clone. Brazilian company Dismac made Apple II plus clones with the same keyboard layout as this one, and the motherboard looks very much like it as well!

@jessiec4128 10 ай бұрын

In the 80s I had one of the Apple versions and I sold it to a local school. I got plenty of money for it. Which enabled me to find anorther computer to find that needed repair.

@anothernate3302 10 ай бұрын

Wow! A Laser! Haven't seen one of those since summer computer class in '92 where we learned to write a dice-roller in BASIC.

@JockMurphy 10 ай бұрын

IIRC Franklin survived to become the same company behind the Franklin electronic dictionaries and ebook readers

@Mediateritorist 3 ай бұрын

Oh man! It was really fun to watch you troubleshoot. You are a great entertainment genius :-) Especially because I'm currently desperate for a similar board (a MEWA-48 / GTAC-2 / West PC-800)... I'm really looking forward to Part 2, in which you'll hopefully track down the error... Your way of troubleshooting helps me a lot with my repair! Thanks and greetings from Germany

@KurtSchefter 10 ай бұрын

I like the credits during the intro... It makes the entire video watchable until the end. 👍

@Matthew_Turner 9 ай бұрын

Love Apple content Adrian and the channel in general! Been watching for almost 4 years now! Keep up the good vids and I'll keep sharing with everyone I know.

@orion310591RS 10 ай бұрын

This is good example to use multimeter with mV scale and use it as short circuit finder. Using LM317.

@ray73864 10 ай бұрын

What usually happens (Not sure back then, but certainly these days), is that the company (in this case Apple) will send out to a variety of suppliers a request for an example product that meets the specifications that Apple sends to them (Such as the Apple IIe case). The suppliers then either come back with an example product or a 'can't supply', Apple then looks at each example that comes back to determine which supplier (or suppliers) they will use for the final product. Now, the losing suppliers should then destroy the specifications that were sent to them, but hey, they just spent all this money setting up tooling to make the example product, like they are really going to let all that tooling go to waste. So, they when Apple finally releases the product to retail, the suppliers who didn't win the contract and who didn't destroy the specifications, start manufacturing 3rd party products, just not officially endorsed or badged. This then means that companies like Laser, etc... have a ready to go product that they can utilise. Other ways it occurs is buying the retail product and then getting all the measurements, etc... to create your own clone of a particular part of it.

@OakCityGamers 10 ай бұрын

Can’t wait for the follow up! Thanks for the video

@bobblum5973 10 ай бұрын

If all the chips are socketed, make sure to check for pins bent under or sideways. The previous owner may have caused a new problem while troubleshooting an existing one, and you're discovering it now. I've seen a bent-under pin soldered to a plated through-hole pad that worked (not socketed) but in the process of getting bent under it cut cleanly through an unrelated surface trace running under the chip. Fun to find, relatively easy to fix.

@thinking-laaf 10 ай бұрын

Is it really hacker space? Or an area not removed to patch gotchas in the design? I see those and/or ic patterns to be able to patch a board...

@bobblum5973 10 ай бұрын

@@thinking-laaf If you mean the grid of feed-thru holes, I remember seeing those years ago. Yes, they were there to allow adding components and "bodge" wires to implement ECOs (Engineering Change Orders) as needed.

@oortcloud210 10 ай бұрын

Really enjoyed this video, thank you. Amazing work. I wish I could diagnose and fault find as quickly as you do! I've fixed a couple of Atari S.Ts with various issues but what takes you minutes takes me days. What it taught me was I really need to get better with my scope!

@dionelr 10 ай бұрын

Love seeing the Laser 128EX again. My brother and I used to write so many programs for that thing. We had these program "wars" where one would build a base in graphics, then the next would animate breaking or taking that base over and so on. We got fairly decent at moving pixels around. Good times.

@tonycosta3302 10 ай бұрын

When I was in high school, my got a board like that and made his own Apple II along with a custom plexiglass case that held two floppy drives. I never heard about Apple selling kits, but it was clearly one of those kits.

@JVHShack 10 ай бұрын

When @jdmcs was working on his identical unbranded Apple II clone on a live stream, it too was displaying garbage on the screen until I suggested in the comments to connect the keyboard. After he did that, it just worked. It seems like before the keyboard was connected, it was running a self diagnostic.

@NavyDood21 10 ай бұрын

I have an unpopulated main board for the Pete Perkins Apple II clone. Was really hoping that was it, but alas its a different illegal copy! Still cool to see, especially love seeing how the layouts between this one and the board I have are so different.

@rlgrlg-oh6cc 10 ай бұрын

There are several methods for locating a low-resistance short on a large pcb. One way is to use a DMM that can display tenths or even hundredths of an ohm. Accuracy is not that important. You probe those two signals at various points on the board. As you get closer to the short, the resistance will drop. This relies on making consistent contacts with the two signals with your probes, since any resistance in the contact will add to your measurement. A different technique gets around this issue. If you have a bench power supply, set the voltage to something like 0.3 volts. This will prevent damage to any chips in case the short suddenly clears. Now set the current limit to 50 mA. If your short is on the order of 1 ohm, that should give 50 mV across it, which many meters can display. Now apply the voltage across the two shorted signals, then probe the same signals at various pts on the board. The lowest voltage reading should be right where they are shorted. You may get the same reading at multiple locations for one of the probes. This indicates that the power supply connection point is electrically between the short and the probe locations. Both of these techniques rely on the pcb traces having resistance that adds to the resistance at the actual short as you get further from it.

@nickmoniker 10 ай бұрын

Very interesting troubleshooting, Adrian!

@marc6340 10 ай бұрын

This video made my stomach tickle because I literally loved that time when pretty much everything was "home brew". The community was much more tightly knit and everyone was willing to share. GREAT video!

@N0Negatives 9 ай бұрын

I had a Redstone ][+ clone with the Z80 CPM and 80 column display card. 1st computer was the MicroAce, a Sinclair ZX80 clone, then a Tandy 1000, a PC clone. Send in the clones ! Fun times.

@tony359 10 ай бұрын

Amazing video, going to watch part 2 now! :)

@michaeledwardharris 10 ай бұрын

I'm r4ally enjoying your channel. Thanks for making these videos. My elementary school definitely had Franklin clones back in the mid 80s.

@TonyHamlyn 10 ай бұрын

Fantastic that you put the board scans online, it looks to make fault finding and modding a breeze using the GIMP scans front and back overlay.

@kevinnollette9803 8 ай бұрын

At swap events in the SF Bay Area (in the early and mid 80's) you could walk through and buy all the parts, choose your case style and keyboard, power supply, etc. and then take it home to put together. Even ROM sets were available for as little as $ 5. I had a case that said Banana on it.

@simonm7848 10 ай бұрын

I have a multi-board Space Invaders machine where the CPU reset pin was shorted to Address line 15 of the CPU. A15 isn't used by the software but was pulsing due to the CPU reset watchdog circuit. That was fun to track down!

@esra_erimez 10 ай бұрын

My dad told me once that there were vendors that sold the motherboards without ROMs as "replacement motherboards" for defective Apples and you just needed ROMS

@mogwaay 10 ай бұрын

Thanks for keeping me entertained on the North Sea ferry service from Shetland to Aberdeen in the UK! Man shorts between data/address bus lines what a pain, maybe there's somewhere those traces run together or maybe that prototyping area has a bridge, oof could be lots of things, good luck, I'm looking forward to pt2, hopefully I'll be watching on dry land next time!

@DavidWatts 10 ай бұрын

Really enjoyed that. Oddly relaxing. I suppose because you were doing all the hard work ;)

@RoyceTaft 10 ай бұрын

Great video! Excited to see you figure this one out. Although it may take longer, rather than using one probe to bounce between pins on a logic IC, I prefer to use 3 or 4 channels on my scope to look at multiple inputs (if necessary) and an output. For example, to make sure a bus transceiver is working properly, I’ll measure and trigger on the direction input pin as well as an input/output pair of pins. This lets me see if one side of the IC is weak and not fully driving the busses. Because either side of the bus transceiver has other sources that could drive the busses, without seeing a pair of pins at the same time on the screen to compare, it’s difficult to prove full functionality. I used this approach on a Nintendo VS arcade PCB and identified almost a dozen bad logic ICs. It helped to pull up data sheets for each IC and use the pin out and truth table to verify proper operation, marking the schematic as a checklist as I worked my way through.

@Anamnesia 10 ай бұрын

Watching this video has helped me (through your repetition) understand some basic fault-finding techniques. I have a PPG Waveterm A - a 6809 based German Music Computer from 1984 - which has developed a fault. I live in a city half-way round the world from where it was manufactured & there aren't too many people who own these things - let alone are prepared to take on repairs. But I now feel confident I have better knowledge & tools to find out what's wrong with it - I think it's the floppy controller.

@SonicBoone56 10 ай бұрын

You should totally put that unpopulated motherboard in a glass display to hang on a wall. Absolutely beautiful.

@claudiuoctavian1972 10 ай бұрын

If it wasn't 53 minutes long, I would have linked this to the definition of "cliffhanger" :-) Can't wait for the next one! Absolute brilliant detective work and love your reaction upon realizing there's a short between two data lines in a rat's nest. I'd trace out the lines on the schematics using two different colors and a 3rd for the chips in which they interact or intersect, but I'm sure you have a better way of doing it. and I can't wait to see it

@robbieburns3564 10 ай бұрын

When I was a kid, I bought an Apple 2 clone like the one you have there with the keypad. That was many decades ago and it's since long gone (I had bought an Apple //e afterwards). Apple clones were on the market before IBM PC clones existed. Most of these Apple clones are long long gone. I found and picked up an Apple 2 clone (no keypad) which is so blatant that it actually says "apple computer" in apple's font on the badge. It's pretty funny.

@LucidSystems 10 ай бұрын

I just recently found this channel. Love it. The one where you found that game in that crt menu was neat... I'd like to see a video about Easter Eggs hidden in old computers. Software and hardware.

@ovalwingnut 10 ай бұрын

Involved with computer since "before computers" but never Apple. Not because they don't RoCk. You gotz to pick a side to play on :) Thank you for teaching me all this old-school Apple core stuff.

@markcummings150 10 ай бұрын

Having repaired a genuine Apple ][ Plus (rev RFI) that I purchased last year which had 11 separate faults I’m really enjoying this video and I’m looking forward to the next one (or two). I only used a logic probe and multimeter to find all faults and didn’t need to crack out the scope. Not all faults will necessarily be chips or components. I had several that were due to corrosion of pins. That book you used is awesome and was the one I used as it has all Apple ][ plus circuit revisions (just have to make sure you are using the right revision). In your case there is that extra difficulty factor of it being a clone with some variations from the book.

@thedorianlondon4759 3 ай бұрын

I feel like I'm watching the Calamity Jane of electronics engineers when I watch this guy trying to fixing motherboards.

@kirkjensen1718 10 ай бұрын

i purchased just such a bare board from the back of Byte magazine around 1984 ish. Soldered up my own Apple II. A friend had a real machine and worked at a company that could make my ROM's. Tons of fun.

@endi7097 10 ай бұрын

you can hear Adrians sanity slowly dissappear as the repair keeps getting more difficult LOL

@rwdplz1 10 ай бұрын

It's like working on old bootleg arcade boards, like Krazy Kong: You're on your own!

@thinking-laaf 10 ай бұрын

I was frequenting a Dutch electronic store which sold blank apple and later ibm pc PCBs like hotcakes. As there were only standard TTL ICs on those boards, people could just build them. The only proprietary chips were the roms, but nothing an eprom could replace...

@Defecato99 10 ай бұрын

I love your repair videos `Adrian. That was a joyous experience :D

@philtimmes1 10 ай бұрын

The video circuit drives the address lines during the low phase of the clock, Adrian.

@jeromethiel4323 10 ай бұрын

I hope it's not a sliver of solder across a trace or pin. Those can be exceedingly hard to find. If you can pull ALL of the chips off, you might be able to burn open a short by applying, say 24Vdc at a high available current. A sliver of solder will open (like a fuse) if you push enough current through it. This is extremely risky, but it can work. You can do the above trick at a lower, safer current if you have access to infrared camera equipment, push in the power and look for a hot spot. Good luck!

@scratchanitch 10 ай бұрын

I lived in Hong Kong in the early 80s and you could buy Apple ][ boards in Apliu Street, which was/is big electronics flea market. Helped to launch me into a career in computing. Taught me how to solder pretty well too!

@SuperHaunts 10 ай бұрын

I've since come to appreciate the computer as itself. Back in t he day, I hated Apples, because I was in the 'Trs80 camp'. With age does come wisdom. It's no longer Hatfield vs. McKoys. I still like Z80 better than 6502, but it is no longer Evil Innate. - Well at least from a hardware standpoint. Company wise, that's another story.

@radman8321 10 ай бұрын

I worked for a UK company that made Apple II clones as well as a range of expansion cards. I think they reverse engineered the roms and did a clean room implementation. They certainly sold them for quite a few years before moving into other products.

@coyote_den 10 ай бұрын

Apple II has interleaved memory access. With the bus transceiver disconnected, you will still see activity on the address lines because the video generation logic generates addresses on the odd phase of the clock. The whole purpose of the bus transceivers is to ensure the CPU is off the bus during video/slot DMA.

@marcelgta594 10 ай бұрын

As a test, replace chip f14. This is the 74ls259, which is not only controlling the display modes, speaker and tape but is also connected to the game io connector c040. Maybe a dodgy apple paddle ot joystick fried the chip. There is no chip protection. Also f14 is connected to a3

@2009numan 10 ай бұрын

I love all the laughing in your videos Adrian

@MagnaRyuuDesigns 10 ай бұрын

I'm betting some of those confiscated clones that Apple acquired probably had some stuff that Apply thought "hey this is pretty good, we'll take that idea for ourselves. I mean come on what they going to do 'sue us'?" :D

@GeeWillikersMan 10 ай бұрын

We had a clone my dad and brother built. I remember when it would boot it would say "Appfel ][+" or a similar misspelling in the ROM.

@LarryRobinsonintothefog 10 ай бұрын

Awesome. Never got anything this harry, but did encounter defective delay lines to memory chips on TRS-80 model-2's and thought abought solder shorting two pins of dip sockets.

@CRB9000 10 ай бұрын

Back in the day, I had an Orange. It was an Apple II+ compatible clone made in Taiwan. Shortly after I got it U.S. Customs shut down their ability to ship them into the U.S. There were also TRS-80 clones coming out of Taiwan.

@hypnotised-clover 10 ай бұрын

I have been wondering, since there were lots of ZX 81, ZX Spectrum, Apple II and TRS-80 clones, were there any C64 clones? It would make sense to clone an already cheap and popular computer like the C64.

@8bitwiz_ 10 ай бұрын

@@hypnotised-clover Commodore used quite a few custom chips, and the rest (except maybe the Sinclair stuff) uses all standard chips. Certainly Apple and Tandy both used only common chips in the early days, with ASICs/gate arrays later only to reduce cost.

@novasater1133 10 ай бұрын

Congratulations for the tenacity Adam, I would check on the new pcb without components if there is already a short circuit! At this point it could be a manufacturing defect of the pcb. greetings from italy.😅

@davidreese9984 10 ай бұрын

Possibly a ram chip for bit 2, that would use both the address line 3 and data line for bit 2.

@8bitwiz_ 10 ай бұрын

There's a multiplexer between the address bus and DRAM, so no way to have a short there.

@CollinBaillie 10 ай бұрын

"..a little piece of the Pie...Apple..." I see what you did there.

@timmooney7528 10 ай бұрын

When I wa sin middle school and high school, we had some earlier Apple models, and quite a few Laser 128's. My assumption is the Laser's were much cheaper

@cmjones01 10 ай бұрын

You need a Toneohm! Low-ohms meter with a tone output, so you can chase around the board with the probes looking for the nearest place to the short just by listening to the tone. It's indispensable on the repair bench.

@anvz6 10 ай бұрын

One approach could be checking low ohm measures and finding where it's lower or higher. Other could be cut some traces and isolating half of the board to see in which side is the short.

@williamsquires3070 10 ай бұрын

My first GOTO would be yanking all 48k of RAM, then checking for the short; MT wasn’t the only manufacturer with flaky RAM chips! Then JMP to your supply of tested good RAM chips. 😅 (i.e “JMP $ram_supply” in 6502 assembler.)

@exohio 10 ай бұрын

I'd watch how you word the title, I could see "Illegal" and "Apple" getting you a cease and desist from them, or a knock on the door from the FBI coming to confiscate your 40 year old clone computers. Someone at Apple, watching your video, pounding their fist "Nein! Nein! Nein!" 😆

@c1ph3rpunk 10 ай бұрын

I’d use the term “unauthorized” if it were me. Apple isn’t known to be nice.

@commodoresixfour7478 10 ай бұрын

Exactly, this includes the guy that was buying up all the Lisa computers from them, upgrading them and reselling them. It's not about the technology, it's about making money.

@kennethflorek8532 10 ай бұрын

Nein! Nein! Nein!😃

@davefarquhar8230 10 ай бұрын

Years and years ago, I saw a web page that claimed something like 160 or 170 different Apple II clones existed worldwide. That site has been gone a very long time but I imagine if someone tried to count now, even more may have been discovered since.

@martindejong3974 10 ай бұрын

you can find a list of apple ][ clones on wikipedia here: en.wikipedia.org/wiki/Apple_II_clones

@urglegurgle5807 10 ай бұрын

Franklin are not gone; they just exited the desktop market and still make stuff today in the handheld market.

@RetroPCUser 10 ай бұрын

The one thing I seriously want to do is fabricate clones of some motherboards that used the NiCd batteries and have them use coin cells in place of them or only a header for a 4.5V battery holder. For example, the one Jetway 3/486 board I have (or had, cannot recall if I still have it or not since I cleared some clutter out of my room recently) was under heavy battery leakage/corrosion and a lot of traces were damaged and repairing it was complicated and it almost worked. I have a working one that had 2 small drips, but I got it cleared up and it runs great. Heck, even for OEM system motherboards, I would do the same thing.