Macintosh 128k Mini-Tour and Black Screen Fix

A Mac 128 that was graciously donated to my channel had a black screen when powered on. Let's take a look at this machine and fix it!
Links:
Commodore Computer Club (of Portland, Oregon and Vancouver, Washington)
www.commodorec...
Serial Number Decoder:
myoldmac.net/FA...
Dead Mac Scrolls:
archive.org/de...

[@SootHead]

Keep it 512. Vintage mod adds to the cool factor.

[@thecaptain2281]

Agreed!

[@dvdbytes4348]

Totally agree.

[@Ramsis-SNES]

+1

[@AndyMarsh]

Gets my vote.

[@dregenius]

Yup, absolutely!

[@NovaSilisko]

I vote keeping the 512K. I like when things like this tell their own story of ownership and usage.

[@James-fm4lk]

Keep it as a 512K. the 128K was really just not enough RAM to be usable.

[@martinmeyer2008]

@Amando Marques LOL :-) Better than asking "But does it blend?"...

[@tarstarkusz]

I concur. If the 512 was available back in the day, there is zero reason not to make it 512 today and frankly, it needs it.

[@jeremymtc]

I adored my 128K, but it was damn near unusable until you added a second floppy drive and made judicious use of RAM disks. I'm of two minds about regressing the memory mod, as on the one hand Adrian may want to experience the machine as it was originally designed and built, warts and all. On the other hand, part of the history of this particular machine (its Mojo, if you will) is that it was upgraded in period for better functionality. Personally I'd keep the mod on this one and find an unmodded 128 if I wanted one for strict "museum" purposes.

[@Patchuchan]

I read somewhere the Macintosh Apple used in the 1984 demo had 512K as the demo would not work smoothly with just 128K.

[@bonno666]

Keep the 512 K, the "original" specs are no longer interesting. Only to collectors to put it in a display. Even then the upgrade is a good thing.

[@joelavcoco]

What it IS is a Mac 128 upgraded to 512k. That is just as legit a thing as an unmodified machine, and is representative of how the computer was actually used.

[@jondorthebrinkinator]

Definitely keep it as 512k. 128k would barely run any software and required tons of disk swapping even with two drives.

[@MichaelAStanhope]

Keep it as it is. It is still a 128k model, still has the motherboard that belongs in it, just modified. A 128k mac is esentially useless, at least with the extra RAM you can do things with it and enjoy it.

[@tarstarkusz]

Agreed, 128k is just a useless machine.

[@nitrax8629]

Keep it as 512K - the modwork is exceptionally clean, and is part of this computer's history.

[@KomradeMikhail]

Keep it 512k. Not because a 128k is frustrating to use as most comments here are saying... But because that is a beautifully crafted mod and should be preserved.

[@Solitaire1]

Keep it as a 512K. The upgrade is part of the history and identity of the machine and should not be erased.

[@dvdbytes4348]

Totally agree.

[@adrianschneider4441]

Leave it as is. Vintage mods are „original“ too. And it is far more usable that way.

[@Runicen]

I can't speak to usefulness, since I never used these machines, but based on your description of the elegance of the mod, I'm inclined to say leave it as-is. Someone put some serious time into crafting that really clean modification and it seems like something worth preserving.

[@dregenius]

Runicen completely agree. That mod has a story to tell. 👌

[@brianmccaig2747]

A shortcut diagnostic trick I discovered many years ago, when dealing with the original Macintoshes that beeped and had floppy sounds, but no video...with the Mac powered on just rap your knuckles on the left side of the case. The issue of cracked solder joints was a fairly common problem. If it is a bad solder joint, knocking on the left side will 9/10ths of the time cause the screen to flicker. Sometimes it even temporarily comes on for a short period. If it does flicker then you know that you can re-solder the cable's connector joints, without removing any boards, without any further diagnostics. This has always worked for me. Enjoyed the demo!

[@doktor6495]

Definitely keep the 512k. The 512k mod seems to be done very professionally. Greetings, Doc64!

[@markwanklyn4195]

definitely keep it as a 512K as it is part of the machine's history and also a nice clean upgrade

[@romanrm1]

7:50 "there's this crucial safety step which I'm not going to show you how to do, so let's just continue!" :D

[@sadmac356]

Yeah, don't try this yourself if you don't know what you're doing.

[@kaitlyn__L]

Necro but: don’t want to be liable if someone tries it after just watching one video and then cites your teachings... though also he’s shown it in much earlier CRT mod videos anyway.

[@jim7205]

Keep it as a 512 and play some paper airplane

[@skonkfactory]

Keep the 512. Even the launch day Mac, up there on the stage with Steve, was upgraded to 512k.

[@skonkfactory]

@@adriansdigitalbasement Apparently the demo software just ran out of RAM on the 128k configuration, so Burrell hacked in 512k of ram to make it run stably.

[@MagesGuild]

The 128 DID have an RF shield. It was smaller than later models, but it was present. Your system had clearly been opened before and someone decided not to replace it: The shield could be a pain to install and align with the rear shell, so some people discarded it, not caring about shielding the signals.

[@dvdbytes4348]

Keep it as it is. It's been 512K for 35 years at the very least. I got 2 compact macs, a Classic and an SE. The SE is stil working perfectly The Classic has a checkerboard pattern problem. I really need to open it, but that CRT worries me.

[@tickertape1]

Dvdbytes CRTs may seem scary but with care and leaving it for 2 days after you turn it on and going through the crt discharging there is zero chance you will be shocked if you do it properly. But be careful I have shocked myself a few times in the analog board itself not with the crt. As there are capacitors but leaving it for 2 days should eliminate that

[@jeromewysocki8809]

Dvdbytes , I experienced the same checkerboard problem many years ago that you mention here. It immediately happened when I accidentally disconnected the keyboard while the computer was still powered on. (The connector got pulled out of the socket.) I never could not fix the problem. Someone suggested that the motherboard blows out when the keyboard is thus removed while the computer is on. Never verified if this was the problem. I gave up on it. Hope you are more successful than I was.

[@tickertape1]

Guys the checkerboard pattern is caused by leaking electrolytic capacitors on the motherboard

[@dvdbytes4348]

@@tickertape1 And that's why I need to open it up, clean the motherboard and recap it. The classic has been turned off for 2 years now. Sooner or later, I wil come round to it. Sadly, I still need to learn soldering, and I don't want a Classic to be my test bed.

[@tickertape1]

The capacitors sadly are SMD soldered which are much easier to desolder but harder to solder than through hole

[@zoomosis]

I've always been a PC guy but have always been fascinated by vintage Macs. I learned a lot from this video. Great stuff. Thanks.

[@deamondeathstone1]

That is such a nicely performed upgrade, it deserves being there.

[@mrlurchAU]

Keep it as 512. It’s an era correct mod. Unsurprised it was bad solder joints. On my Mac Plus I found so many iffy joints, I reflowed the entire board. Looking forward to future classic Mac vids 👍

[@RetroRick1990]

It is so pleasant to see something like this being fixed and back to work again, repurpose old tech is so rewarding 😎✌

[@dondondon786]

disabling the mod would not restore any authenticity. Would then be both modded and crippled, worst of both worlds

[@bruwin]

That's my thought on it. The original chips that were replaced aren't there, so there's no reason to cripple the system for authenticity. Also, the way it was modded is actually really cool and professional. It'd be a shame to remove that work.

[@RacerX-]

Awesome! For sure keep the 512k. There's a reason Apple upgraded the RAM so quickly, 128k it just not enough beyond tinkering.

[@Mobin92]

8:00 You will get the shock even if the machine is NOT connected! The charge just stays in there if it has been recently powered on.

[@corvus00]

Keep it 512, Adrian. You and the Mac will both be happier in the long run :-)

[@DisplacedGamers]

Great work as usual, Adrian! If the "secondary" circuit change for the RAM upgrade can essentially be disabled by desoldering a single wire (similar to a RAM upgrade I have done to an MSX2+), then you could put the functionality on a switch to go from 128k to 512k or back prior to powering up.

[@Eightbitswide]

"I'm not going to talk about discharging the screen." -- Adrian neatly avoids a landmine topic. ;)

[@solitairepilot]

Thank you, Adrian! This helped me fix up my first Mac about a year ago and by now I have two that I’ve gotten working!

[@manwithafork]

The memory mod was done very well and doesn't detract from the authenticity of the unit. I vote to leave it in :)

[@rivards1]

That Mac was manufactured in the 24th week of 1984... it is now the 24th week of 2019... your Mac is celebrating it's exact 35th birthday right now!

[@armpitdew]

25yrs ago i used a long philips, a torx bit, and electrical tape. surprisingly worked great. then replaced the bad DRAM chips. and always admire the signatures inside the case.

[@danielueblacker9118]

13:42 No smoking allowed by the work table.... oh oh... Love your videos found your channel yesterday and have binged watched with enjoyment.

[@stuartnaulty6821]

Leave it 512K. Not very useful with only 128K. You can always revert back in the future if there is a need to.

[@stuartnaulty6821]

If you say change back instead of revert back in your part of the country, that is fine. This is a global forum and we are going to have differences in language. Both mean the same thing to me.

[@et_yt_official]

He wanted to make it original

[@TrashfordKent]

Used to work on these in the late 80's, Leicester & Loughborough University had a ton of them, lost count of how many boards we replaced...ps keep the 512k, it's not like it has the original chips anyways. Great vid, cheers.

[@achimboers]

Keep it at 512. This modded versión in its way is also an historic correct version and it seems nicely done

[@shmehfleh3115]

I bought a Mac Plus off eBay not too long ago. It came with the original battery still installed, an old-school tin body Energizer with the thin copper-colored stripes. Although it was deader than disco, it miraculously hadn't leaked. The computer itself worked great. The old beige Macs are so much more reliable than the putty-colored ones that came later.

[@Slider2732]

AHA! that's exactly what happened to my Mac... a bunch of lingering smoke. Plus I now know how to get those screws out of the top. What a great vid, thanks :)

[@SikSlayer]

Just leave it as is I say.

[@BreakingBrick]

Save 512, save 512, save 512, save 512... And quite remarkable, nobody thumbed it down. Great work Adrian!!

[@Kawa-oneechan]

"The shaft is too thick and it will get stuck in there." That's what she said.

[@jeffwads6158]

The people talking about the 128KB version being useless never used it back in the day. It is perfectly fine.

[@FarrellMcGovern]

A trip down memory lane...I was a volunteer at one of Apple's Demo labs for Education here in Canada at the Carleton Board of Education in Ottawa. We started out with Apple ][+s, then we got the //e's and one Apple ///. All of our Apple 2 series computers were networked with a Corvus Constellation network which gave us centralized storage for all the software we used, and tested. We had one of the first Apple Lisa's in Canada...And then one of the first Macs. Wow, that was amazing stuff for the day. I went on to become a full-fledged tech, working on Apples of various flavours, PCs, etc. Very fond memories of the Mac 128K. BTW, that interrupt button on the side with the reset button was known as The Programmer's Key. :-) en.wikipedia.org/wiki/Programmer's_key

[@manolisgledsodakis873]

I had a Mac Plus many years ago (1987) and I acquired the correct screw-removing tool, which consisted of a long piece of hex cross-section hardened steel wire with the end bent to form a large handle. I still have it, somewhere.

[@ForDBssake]

It's such a well done mod please keep it.

[@Robert_Wolf]

Keep as 512k. The computer has history of being upgraded.

[@TheSulross]

Had a 128K Mac - thought whoo hoo twice as much memory as my Commodore 64 - and the Motorola 68000 could address it directly. But the 128K Mac proved to be useless - completely nothing but a novelty piece. There was an instruction sheet making the rounds in Mac circles, though, that was how to upgrade 128K Macs to 512K. So I took the plunge, desoldered all the 128K chips from the motherboard, soldered in sockets in their place, plugged in denser chips to achieve 512K, and then soldered a jumper wire onto the motherboard. Voila it worked! I then had a usable Macintosh computer. Went on to become a Mac programmer (my favorite was Lightspeed C and Macbugs monitor/debugger). First job out of university involved programming the Macintosh Plus for a paycheck.

[@rogerjones8809]

I also vote keep it 512, it was a professional installation. Nice that it is still a 128 motherboard though. Like I say I worked at dealerships for 9 years, had all the factory parts, and it was great to swap parts to diagnose and repair. Also turnaround was very fast. Now 30 some odd years later, it’s nice to know how to component repair original parts and give these things extended life. I one time only, accidentally touched the side of an analog board with shield removed, never did it again, was only a mild shock. A safety reccomendation from me would be to always keep one hand behind your back when doing any live video adjustments and of course the right tools so you don’t make a path through your body.

[@stevenjlovelace]

I'm glad to see that most of the other commenters agree with keeping it 512k. The 128k Mac was essentially just a way of advertising a lower cost, and the stock 128s were so unusable that it's no wonder that so many were upgraded. This upgraded one corroborates that story.

[@CBSBKKAMcomputerhelp]

Just like the others says: Keep it at 512k because more is better.

[@adventureoflinkmk2]

#GoBigOrGoHome

[@mwicker777]

Absolutely leave it as 512K...I think this still preserves the history as this looks like a very well done mod from back in the day.

[@JanBeta]

Nice fix and a beautiful early Mac. :) I still have to refurb my little Mac collection (didn't realize there were dreaded RIFAs in there, too, so thanks for making me aware of that).

[@setlonnert]

Feel for this video in two ways. One, I'm from Sweden and long time ago visited the L M Ericsson factory at Telefonplan, Stockholm, where they had an overwhelming amount of RIFA components in boxes to be inserted in some equipment. Perhaps was it was for the landline phones, don't remember. We were proud youngsters, that Sweden manufatured electronical components, at least at that time. After watching Adrian being worked up from faulting capacitors, I'm more embaressed than proud. Sorry! Secondly, I worked at a small company where they had aquired a Mac 128k. Soon they upgraded it to 512k. Later they also bought a license for development. Intended for me. Yes, Apple already then made money from keeping developers in a tightly closed loop. I used the Mac for writing a manual for a "smart card" (cartridge) extending BASIC for a ABC80 machine, that the company manufactured. The solution was quite interesting switching banks and transfer parameters on the shared stack. Well, I had a different vision of the future where Mac was in, and the Luxor ABC80 was out, and a sceptic to the recent IBM PC XT. Ok, so I was partly wrong. But boy, if we had gone in another track ... Well, I quit. And ... I'm neutral in keeping it 128 or the upgrade 512. It reminds me both of another age.

[@esseferio]

Keep it 512k. If collector score is important, the mod itself is period correct :)

[@lambertax]

I was servicing these Macs in Paris at an Apple dealer. Already, at the time, this capacitor had problems. So I imagine that 30 years later ... I remember perfectly that we used the long screwdriver to discharge the high voltage by making contact with the chassis. There must be some torx screwdrivers left somewhere. By the way, the audio output is analog. Souvenirs :)

[@buddyshearer4170]

Great site. Thanks for doing this. I have 2 Macintosh SE/30's, a Macintosh Plus 1MB and a Macintosh IIcx in my garage that I have collected from people. Not being a Mac guy I have no clue about this boxes. Now you have given me a starting point. 5 Thumbs Up to You!

[@freednighthawk]

That's the cleanest 512k mod I've seen. I'd keep it. Someone knew exactly what they were doing, probably a computer store. Leave it as is!

[@andreasmuller6333]

Keep the 512K! It was made so professional it deserves to live!

[@furiousdriving]

Keep it 512, a vintage mod for a a vintage Mac, and the computer equivalent of a Q car!

[@xephorce]

keep the 512kb of ram trust me you may need it sometime in the future

[@ultrametric9317]

I was actually finishing college when this came out. My office mate had one, while I used an HP-71B handheld computer - we were physics students at Ga. Tech. My 71B could do matrix calculations, complex numbers, and had 32k of RAM. I had that thing turning handsprings. It was incredibly useful in my work. His Mac could do nothing of any use whatsoever in physics :) I absolutely hated that toy! And it cost a fortune at the time. If not for the Apple II series, Apple would have gone under in 1985. It's a miracle they survived. They were still light years behind the X86 world when bus mastering and co-processing arrived in the late 80s - early 90s. It doesn't surprise me that Steve Jobs himself was against arrow keys - maybe the dumbest thing I've ever heard. /rant Anyway good work as always. You never know when you'll need a doorstop!

[@absurdengineering]

Ultrametric You could have written lots of useful scientific/engineering software in e.g. Pascal for that thing. Basic linear algebra is not hard to code up, and even back in the 80s there were numerical methods books and scientific computing books to learn from. You didn’t even have to write the stuff in assembly, like many others. It’s a bragging right as much as a “sad” reality when one can whip out a usable floating point “kernel” for almost any CPU in a day or two, after using assembly here and there for 35 years… it’s fun and it doesn’t get old but yet it does get old. FFTs I have to draw out on paper first, still :/ Complex number operations can be easily done in a floating point BASIC, even on something as puny as C-64. The Mac 128k did a splendid job in scientific applications, it was just a wee bit harder to know where to start without the benefit of Internet to easily search for stuff. In any case, 68k assembly was way nicer to work with than Z80 assembly, if push came to shove. I was “bound” to Z80 and 80x86 for quite a bit before I got an Atari ST and got a chance to learn about the 68k architecture. It was like a whole another world. It was refreshing. All those addressing modes!

[@martinmeyer2008]

Keep as much RAM as possible...its always reversible if required, but based on your Commodore power connector videos, I think you are a function over form person, so having more RAM is more functional! Great video :-)

[@More_Row]

Keep it at 512K , good video man ! 👍

[@8bits59]

The Mac 128 was the first machine to ever support a 3 1/2" floppy drive, actually. Apple and Sony had an agreement to make these drives for the Mac so that they weren't using the weird "twiggy" drives à la Lisa.

[@PicaDelphon]

My I would keep the 512K in the unit, so many programs don't run on the 128KB board.. But I have too many SCSI Devices, CD-R, DVD, Scanner, ect to o be with out the SCSI...

[@808v1]

Excellent vid...I have a 128 and 512 (running currently), that Dead Mac Scrolls pdf will come in handy though. Thanks for informing of its existence.

[@Psychlist1972]

Small correction: The audio jack on the back is normal 1/8" mono analog audio. It's not digital audio.

[@brianmccaig2747]

Agreed, definitely not a digital audio port.

[@kaitlyn__L]

Sure, it’s not digital like a mini-SPDIF on a more modern Mac. But the original Mac itself does have digital audio at a sampling rate (forget what it is, it’s lower than hifi, but decent for the time. Probably 11 or 22kHz), rather than just having a hardware music/sound chip. Obviously that’s put through a DAC first though. And in that regard it was ahead of its time.

[@Psychlist1972]

@@kaitlyn__L Agreed. But that has nothing really to do with it. It's not a digital audio jack :)

[@kaitlyn__L]

@@Psychlist1972 “Apple was relatively forward thinking for 1984, giving this computer digital audio” - he didn’t call it “a digital audio jack”.

[@Psychlist1972]

@@kaitlyn__L He pointed to the jack and called it digital audio. It was a very small mess up when he was discussing the back panel connections. The full quote, starting at around 1:59 is: "Taking a look at the back of the machine, Apple was relatively forward thinking for 1984 giving this computer digital audio, a built in mouse port, floppy, and two serial ports. Note that it wasn't until the Macintosh plus that the computer had built-in SCSI." It's hard to hear that as anything other than mistaking the jack type or simply misspeaking. But, importantly, "digital" is not the same as "sampled" audio (or sample playback). Most of the popular computers of the time had digital audio ranging from the most basic beeps and 1-bit samples on the IBM and Apple II to hybrid digital/analog synthesis on the Commodore 64 (digital oscillators, analog filter). It was all digital inside at the generation of the audio, but it wasn't "digital audio", which implies something else. :) Aside: this interested me, so I just looked up how the original mac did its audio. This is what the Mac 128k tech details say: "The sampled sound engine piggybacked on the video circuit. As the raster scan returned from the right side of the screen to the left, one byte of data was placed into a PWM generator instead of the screen. This provided 8-bit sampled monaural sound sampled at the 22.25 kHz horizontal blanking rate. General purpose 6522 outputs could mute the sampled sound, or set its volume to one of 8 levels of attenuation. A square wave generator was included on the 6522. One of its two timer circuits could be set to toggle the mute output periodically. This could produce frequencies higher than 11 kHz.". That doesn't change anything, it's just a point of interest, because now I know it was 8-bit 22.25K samples audio, which was indeed novel for the time. I'm not trying to take anything away from the classic mac. It was a ground-breaking machine, and sample-based / waveform-based audio was very cool.

[@samsulummasamsulumma6898]

Brilliant work and presentation!

[@RossTheGenMan]

Keep it as 512. The mod is part of the history of this PC. Its still a 128 motherboard. You may find a 128 still with 128 down the road.

[@deborahberi3249]

Leave IT AT 512 imho.... Another Solid Vid btw! .-Mark

[@joseph9770]

Keep the upgrade!

[@michaelgeleff4991]

Great video! Took me back to my days when I had my 512k. I had the same issue, but to temporarily fix mine I would smack the side and the picture would come back. My step-father and I would take the cover off (he had, and I think still has, the long torx driver to get to the recessed screws) and repair those solder joints. We had to do this twice until he gave me his Classic. The other issue I had with this model was the auto eject stopped working and I had to use a paper clip to hold the disk up and use a pen or other pointed device to get the disk out. I think you should keep it as the 512.

[@ReallifeBambiDeerattheFarm1]

Keep it as is. No real need to downgrade it.

[@CommodoreFan64]

leave it as 512K it will make the machine more usable.

[@MatroxMillennium]

I also made a DIY "Mac Cracker." I bought a couple of normal Torx screwdrivers at the dollar store and cracked the handle off one. I was then able to use the handle from one of those removable bit screwdrivers to drive the newly freed Torx driver shaft.

[@Doctom91]

The mod is so beautifully done that would be a crime to touch it. Leave it!

[@furiousdriving]

I had the smoke of death from a 1992 Powerbook Duo PSU when I plugged it in for the first time in years recently. Is this in any way repairable from your experience? Thanks, Matt

[@dave4shmups]

Nice! In the late 1980s, my Dad got a 512K. I mainly played NES games at that time, but I did play a LOT of great games on the 512K! Sim City, Arkanoid, and Beyond Dark Castle II, to name a few. Beyond Dark Castle II is still one of the best action adventure games that I've ever played! I don't have it anymore, but I've been told to get a Macintosh Classic, because it has the 68000, whereas the Classic II has the 68030. I think you should revert it to a 128K.

[@coyote_den]

The shiny/smooth spot on the case is wear from people feeling for the power switch. It wasn't there from the factory.

[@classiccomputers6211]

Something of note is the fact that your machine has an 800K half-height floppy drive installed while the machine originally came with the full-height 400K drive you mention at the beginning of the video. This means the ROMs were also upgraded, likely at the same time as the RAM (which I think you should keep, by the way, it increases usability quite a bit).

[@classiccomputers6211]

@@adriansdigitalbasement Yep, exactly! It's really common to see 128K and 512K machines with that ROM/floppy upgrade (and the logic board swap/"RAM upgrade" you talked about in the video), I'm pretty sure it was a program Apple ran for some time. In fact, out of the five or so 512K's I've ever owned, only one has had the original 400K drive still in it.

[@LanternLabs]

I say keep it 512k, those homemade upgrades are super cool

[@user-vn7ce5ig1z]

19:20 - Many years ago, the Turkey computer virus would do exactly that, focusing the electron-gun on a point to cause permanent burn-in on your monitor; it is still one of the few viruses that could actually cause hardware damage (another one being a virus that would read an invalid floppy sector to cause the motor to slam against the block until it became uncalibrated, though that wasn't necessarily permanent).

[@MrJackSeverity]

Top work. I have a plus that I have to tap the side every so often, the screen goes black. might have a good look after watching your vid. I think leave the old girl 512.

[@KelikakuCoutin]

Thanks for the great video, and for saving our heritage in computing. As far as the absence of arrow keys, I didn't ever hear that story about it. As I remember, it was more that the concept of "arrow keys" had not dawned on anyone yet was the reason for their absence. It was not that they decided not to put arrow keys on the keyboard. It was more that arrow keys just hadn't been "invented" yet. They were modeled after typewriter keyboards, which never needed arrow keys. I could be wrong, and the Steve Jobs story might be correct. That's just what I remember. Thanks for the great content. Keep up the good work. בס״ד

[@awebuser5914]

Neat video, but there's one feature that you didn't notice in the teardown (at least at the time...) The second you opened it, it was obvious it was a 512 upgrade! :) How did I know, you ask? The floppy drive was an 800k Sony 51W using the brass-coloured Mac Plus bracket. An original 128 or 512 would have an aluminum bracket with a much larger, more "klunky" Sony 400k drive. Also, as part of what was known as the Mac 512kE ("Enhanced") was a set of ROMS from the Mac Plus that allowed the 800K drive to be used (you'll see the part numbers ending in 221 and 331), as well as a bunch of other ROM code updates, most of which are transparent to the end-user. See: en.wikipedia.org/wiki/Macintosh_512Ke

[@Michael500ca]

Used these in my final year of high school computer science.

[@talonfluff]

If the crt is unplugged (unless you have heart condition or something else) the high voltage wont kill you . I've ben zapped from one that broke off while dissasembling one of broken crt's for scrap. It's not the voltage or current that kills you. it's the energy.

[@glonch]

My vote: 4*128=more better... Great video!

[@te71se]

Right off the bat.

[@FernandoelChachi]

Nice to see that I'm not the only one having a smoke/fire problem with vintage computers. I hadn't seen anybody having this problem and it happened to me just a couple of months ago with a C= 1551 floppy drive. Neither Ray Carlsen had ever seen this. Of course I posted about this problem at the English Amiga Board: eab.abime.net/showpost.php?p=1314714&postcount=19 What I did was to leave it working without replacing the filter.

[@DiscoverLifeMedia]

I'm digging it!

[@robintst]

It came from a Commodore Club member? What did he say? "Need a new home for my Apple foster child, the C64 and Amiga 500 do nothing but torment him endlessly."

[@P5ychoFox]

I’m currently working on a similar problem on a power board from an Amstrad PCW. Hopefully mine will turn out like yours. Another great video. I’d vote to leave the Mac RAM as is.

[@donokono]

Nice work getting this back to working condition! I'd leave the 512k... It's something an owner at the time would have done.

[@jjeffers88]

Keep it 512k. It adds a story to its previous life, and ultimately makes it more useful.

[@pentiummmx2294]

thats part of retro computing, things can die, like from failed capacitors, cracked solder joints, etc. so some tinkering, electronics knowledge, and having the tools available (Soldering iron or station, a desoldering iron or solder wick or a desolder pump, flux, solder, etc.) is recommended.

[@Techokami]

Chiming in to say that it should be kept as a 512K. It's a 128K motherboard that was actually made to be useful.

[@RonLaws]

Leave it as 512k, that mod has story behind it, it is still the original motherboard and reflects how the machine was owned and used during its service life.

[@thecaptain2281]

@Adrian Black My vote, leave it 512k. Why would you down-grade? If there's a functional reason to do so, then maybe it might be worth it. Otherwise no way..