This iMac G3 Has a Terrifying Problem... Let's Fix It

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THIS is a 1998 iMac G3 Rev B, which I think is the best of all the trayloaders for several important reasons. What's not great is the terrifying electric arcing sound that's coming from inside while it's running...
Let's fix it, and get it ready for an extremely rare CPU upgrade!
LINKS:
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🍎 MOOT Teardown Video (Extremely Helpful!): kzbin.info/www/bejne/gaqvoqluYsyWn7M
🍎 IFixit Guide: www.ifixit.com/Device/iMac_G3 (has slot loader and tray loader!)
🍎 Dielectric Grease: amzn.to/3nuWgvn
🍎 Flyback source: technotronic-dimensions.3dcartstores.com/6174Z-1003G-AppleMACIMAC-Monitor-flyback-new_p_46.html
(Amazon links are affiliated links)
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💾 For more vintage Apple stuff, please subscribe: kzbin.info
💾 Support these retro computing shenanigans on Patreon! www.patreon.com/ActionRetro
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Check out my Amazon page with links to my tools, adapters, soldering equipment, camera gear and more: www.amazon.com/shop/actionretro
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💬 Come talk about old computers on the BitBang Social Mastodon! bitbang.social
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#Macintosh #PowerPC #iMac

[@MichaelAStanhope]

we need all of the shenanigans!

[@orestes1984]

Can you imagine that the revision A and Revision B almost used a standard monitor cable and were basically computers rather than "all in ones?" later models revised that...

[@gustiwidyanta5492]

Good old Apple

[@sjgrall]

Surprised me the first time I took one apart

[@orestes1984]

@@gustiwidyanta5492 this is back when Apple were still thinking about the possibilities of expansions. I think a lot of this was a rush to market though. There are so many features of the Rev. A And B iMacs that just scream…. I wasn’t quite ready for market but we’re going to launch anyway….

[@sjgrall]

@@orestes1984 my understanding is it’s the DB-15 video connector used on 80’s and 90’s Macs, nothing special. However, what it can drive is likely dependent on the video chipset in your revision (A-D), and Apple could also have hard coded in the values potentially in software. I vaguely recall others having success connecting an external monitor this way when the internal display wasn’t working.

[@grevillewhittle9771]

It was a standard Mac video port. Someone modded a 21"mac crt and fitted the iMac computer parts (from the slide out tray) into it, sorry I can't find the links. I plugged a mac to VGA adapter in the port when the internal CRT started to die and used a 17" crt with it.

[@GeekmanCA]

Sean your anguish while working with those plastic snaps was something I felt deep in my soul. Even when I'm opening modern computers for my day job I'm always mortified I'm going to break one of them and not be able to get the machine back together properly. I hate tabs so much.

[@sulliops]

This is me working on any repair. I know a fair bit about repair, yet I still manage to break something every time. I can't imagine working on those particular plastic tabs.

[@scottthomas3792]

I had an old E machine with a similar problem...from the word " go" , you would hear random loud arcs, and the screen would flicker...the high voltage connection at the CRT was loose, and no silicone grease. Side note..that high voltage silicone grease is a corrosion preventing glop as well. Two jobs ago, we used it on light bulb bases ( thin layer!) If equipment used in harsh environmental conditions ( trucks and tractors used as snow removal equipment)...no more bulbs corroded into sockets...

[@bitsmasher101]

Anyone else living Saturday to Saturday, just waiting in anticipation to see what atrocity will be carried out next on a retro Mac? Just me?

[@CasioMaker]

Not just you. I wait for the end of my shift at work, to sit down and enjoy some shenanigans

[@UpLateGeek]

Yeah, they need the x-ray warning because those larger CRTs require >20kV anode voltage, which creates some x-rays when the electrons strike the phosphor. The front glass in the tube is usually leaded, which shields the user from the x-rays, but operating the CRT with the rear shielding removed will allow some small amount of x-rays to escape. You'd probably get a lot more radiation from a dental x-ray, so it's probably not worth worrying about unless you're standing to the side of an unshielded CRT for an extended period. But you smartly put the shielding back for testing, so absolutely no issues there. Cheaper monitors won't have that shielding, but they're usually designed to direct the x-rays towards the rear of the monitor rather than to the sides. And again the doses are so low that standing a couple of metres away would probably only be marginally over background levels of exposure. I imagine a teacher standing in front of a classroom of monitors with their rears towards them may receive a higher dosage, but we're still talking around the level of a chest x-ray or so per year, which is well within the safe allowable dosage for a normal adult.

[@WarthogRacer]

My middle school had some tray loading G3s iMacs, despite being a Windows school. They had bondi blue and orange ones. I remember one year, there was a mix of both tray and slot loading iMacs. So there were computers with puck mice and the newer magic ones.

[@nixonhoover2]

Could you watch gay porn on them?

[@lambertovitali3152]

I sold all my school's ones. £50 each in 2007. Seems they're worth £150 now, should have stored them somewhere.

[@RicardoRamosRetrocomputacao]

The only problem I usually see in these imacs is the accumulation of dust + humidity, which over time ends up becoming conductive. A simple cleaning of the flyback tube and cable will solve the problem. But it is an extremely dangerous process, I recommend that you leave your equipment turned off for a few weeks before disassembling, as the tube and flyback can store a lot of voltage even when unplugged. Or, if you have some experience, discharge them using a screwdriver and a ground wire.

[@Mueller3D]

Most modern equipment has bleeder resistors on big capacitors and CRTs, so usually leaving things off for an hour is plenty. Of course, it's always best safety practice to not depend on this until you know it to be the case. Measure the capacitors, and discharge the CRTs with a chassis ground wire with a 1M-ohm inline resistor.

[@charliesretrocomputing]

He discharged it off-camera.

[@simonzinc-trumpetharris852]

Short to ground.

[@sbrazenor2]

I'm always impressed by the collection of rare Sonnet stuff you're able to find. I used the frame by frame view on KZbin to see the box. 🤣

[@GeFeldz]

I just spammed my spacebar and, who'da'thunkit, there was a clear frame there visible within a couple of seconds =D

[@Brok3nC4rrot]

let's face it, when Sean teases a rare upgrade, ten to one it's gonna be a Sonnet

[@sbrazenor2]

@@GeFeldz if you hit 'K' it pauses the video and then the , and . buttons advance a single frame backwards and forwards. It's less of a pain than using space to try to get a lucky frame lock.

[@KiraSlith]

These cards are silly expensive for hobby play to just get 1, let alone owning multiple.

[@sbrazenor2]

@@KiraSlith just about everything that company makes is always expensive. I was looking at some of their thunderbolt computer accessories at various times and those are expensive. Their specialty hardware for niche processor upgrades has always been astronomical. And as the stuff gets older and more rare it's just going to be worse. While I have some hardware that is compatible with those niche parts, I've mostly kept everything period correct and unchanged from stock specifications. When I want to use something more powerful, I just can. (If a G3 doesn't have the power I need, a G4 will. If that doesn't cover what I need, a dual G5 should, etc.) I have all of tiers of Apple products covered from 68K, to PowerPC, Intel, and even up into M-series. (The trick is to buy when it's bottomed out in price, before anyone thinks of it as a collectible.) 😁👍

[@m.j.carlson8246]

My first Mac. Bought it from a school for $100, and I still have the keyboard. Thanks for showing this.

[@NightWolfx03]

So the X-Ray warning is because if the tube ever operates at too high of a voltage, it will start emiting X-Rays so there's alot of protections and parts in there that have to be replaced with the right parts to prevent this.

[@lambertovitali3152]

Safety third.

[@TimothyCizadlo]

That moment when you pause the video, rewind, and watch at 1/4th speed to see what the box he teased was. It's a Sonnet Harmoni G3 card.

[@LotoTheHero]

Hey! 90's grime is the best kind of grime! We called it "Grunge". 😉

[@another3997]

"Well, all the way back to life. It's not dead". Knowing how you approach most repairs, I was half expecting you to say "... yet!"

[@Wind5387]

Had the exact issue on my rev A iMac when I first got it, but the previous owner said it had been sitting for years and it was pretty dusty inside. I blew out the dust and would let the computer run for a good 30-60 mins a day and eventually the flickering just about went away (it still happens but very infrequently now). Nice video!

[@gkhaled1]

These videos warm my heart and remind me of a wonderful time of my life. Keep ‘em coming Sean.

[@nixonhoover2]

A time in your life you watched gae porn?

[@nukfauxsho]

That flickering sometimes is caused by the deflection IC failing or bad joints on it. We used to work on those all the time on Sony and Toshibas.

[@JaredConnell]

This was the first computer i bought with my own money when i was a teenager. I loved it so much but i never opened it up so it's cool to see you do it. When i finally sold it, i had a usb hard drive that went with it and the dude i sold it to opened the computer right up and popped in the external hard drive like it was nothing. I was so amazed and msd at myself that i never thought to do it lol. Thanks for the blast from the past!

[@tookitogo]

6:14 I worked at a couple of little Apple resellers back in 1999 (and as a Mac consultant after that) and sold many CRT iMacs, and RAM upgrades were a common option at the time of purchase and in the years after. We never used a pick to get the case off: just flip up the handle where the screw is, and tug on the handle. It sounds like it’s tearing, but it comes right off. All of the translucent plastic is polycarbonate, not ABS, so it doesn’t hurt it. You definitely don’t need to worry about breaking it! (Unlike the opaque ABS inside, which you saw was yellowed and brittle.)

[@ConorBurrow]

I’ve got exactly the same issue on my Bondi G3 and you’ve inspired me to give it a go and fix it myself 😊 still have the original keyboard and puck mouse! Will let you know how I get on hopefully it’s the same simple fix without having to replace the transformer…

[@ActionRetro]

Awesome good luck!

[@JaymeEduardo]

@@ActionRetro I think you should replace the flyback anyway, it will fail at some point and you will need to crack this thing open again. Had mine replaced back in 2018 and still rocks with BSD. Take extra care with the inner grey plastic, specially in the lower parts where the acrylic fits, and with the CD faceplate. I always remove the cd faceplate before opening it, less prone to break it.

[@garrykanter5773]

First thing I've watched today, and in no time Sean does that "sneak preview"! Great start to my YT watching!!

[@goddessesstartrekonlinefle3061]

Thanks for sharing your G3 journey with us all!😄

[@userperson5259]

Those computers really are super neat. I used a Windows PC at the time and used to mock my many Mac user friends at college because they were sort of slow in comparison. But those computers offered so much more than just horsepower. They were and are beautiful and were a joy to use.

[@ray_mck]

I used my Rev. A (bought for release day) Bondi Blue until one day, instead of making those little zaps and flicker, it made a LOUD zap and never turned on again. It's been in storage since, and I'm really dreading opening it again after all these years. The plastic sounds cracking when it when it was new were terrifying enough. If I recall correctly, there was an Apple Tech Note saying the horrible cracking sound was correct when opening these. Now with brittle plastic, it's even more nerve-wracking. :(

[@ZeroHourProductions407]

These shenanigans would make Steve Woz proud. And anger Steve jobs to no known bounds. On that principle, I would call this endeavor a double win. 🎉

[@cmantac6588]

As always great video!!! Love the old apple tech and sending support from Pittsburgh!! Keep up the great work and content!

[@375-Productions]

Discovered your channel through the Power Mac G5 video! Definitely subscribed!!

[@bryans8656]

Another fun video --- thanks!

[@nougatsa]

Thank you for that trick.

[@Drucklufttroete]

The ball passing through the flipper may have been because Space Cadet relies on x87 floating point calculations that maybe aren't emulated 100% correctly in your PC emulator.

[@willkelly4701]

Did u mean x86 as in the architecture or an opcode called x87

[@Drucklufttroete]

@@willkelly4701 All x86 CPUs before the 486DX didn't support floating point and needed an external FPU, for example an 8087. Later CPUs have this built in, but the floating point instruction set is still called x87.

[@nixonhoover2]

Nerd.

[@luridsorcerer]

Nice video! I just picked one of these up yesterday and it has the same problem. Hoping a simple cleanup will fix it as well; seems like it may have been stored in a garage or basement for many years and it's filthy inside and out.

[@zh84]

Oh, the flyback transformer! That failed on my 1988-vintage Macintosh Plus, and the display closed up into a vertical line. Interesting it was a problem that continued ten years later.

[@adamreid5901]

Well done for the correct pronunciation.

[@morecrappysketches]

Ah, a Harmoni G3. You got me all excited thinking you had one of the Voodoo 2 mezzanine cards!

[@ActionRetro]

Spoilers 😬

[@slembcke]

Boy, that brings back the feels. I took apart soooo many of those 20 years ago when I worked at a local repair shop. I got pretty quick at it eventually. Every time there was a big lightning storm that came through there were a handful of machines that would come in with bum power supplies, and a handful of those would be iMacs that had to be entirely disassembled to replace that. >_

[@frankwhite2072]

Good job!

[@wagnerpanther]

Looking forward to your follow up video with more shenanigans as I recently acquired the same Rev B with the same Harmoni 600 Ghz upgrade from someone that oddly enough was aware of the update being there but likely unaware of its value, so I got the entire thing for less than 100 USD. This Rev B is incredibly picky when it comes to SSD's: * the red Startech IDE to SATA adaptor causes the computer to not even do the chime * the cheap IDE to SATA adaptor (with the master/slave pin) works but disc can't be formatted with any OS 8/9/10. I have tried at least five SSD (8GB, 32GB, 64GB, 120GB x 2) * the only thing that kind of seems to work for now is a cheap BIG RESERVOIR 16GB IDE SSD with a 40 pin to 44 pin adaptor. I can only get 8.6 and 9.22 to work though and I sometimes get odd disk errors that only DiskWarrior can fix. * 44 pin to M2 enclosure with 120GB M2 SATA SSD doesn't work using the same 40/44 pin adaptor above. I can partition the HD once but HD stops being detected by the machine after that and I can't repartition again unless I take it out. I have used a lot of the usual G3 tricks (aware of the 8gb boot partition limit, have tried cable/master settings whenever available, etc.). I may end up sticking to a 7200rpm GB as I have several in multiple sizes (40, 80, 120) but I am often more interested in the set-up process than in actually enjoying the final product. :)

[@rebootretro]

Glad you were successful! I have a dead parts unit (early Blueberry) I was going to offer you the analog board if you couldn't get yours going. My experience is that usually you can see fractured solder joints; if they looked fine, I'm thinking the goop corrected leakage and arcing. And yes, those things are sooo brittle these days! I cringe every time I take one apart!

[@isaacwatanabe9599]

My imac has this problem and im glad theres a fix

[@willyarma_uk]

I heard that if you have a CRT thats doing that crack thing, it sometimes fixes itself if you just leave it on for a while, it happened to the iMac i bought and worked. That said the cracking was much smaller than what you were getting.

[@TranscendentalAirwaves]

Man I wish I'd done this with my old Rev A Bondi Blue iMac when I had it. I had the exact same flickering issue.

[@mickikaufman5360]

Rocking those extra firm Tortex green picks like a boss

[@reedreinfeld3737]

*FLICKERS* “Damn it!”

[@Ramza042]

I have a very similar Mac with the same exact problem. I'll have to take it apart one day and see if I can fix it. 😊

[@atomikrobot300099]

Looks like my newly acquired Grape iMac (333 MHz) has the same CRT issue! Thank you for all your videos and entertainment! I will restore it!

[@abigguitar]

I'm wondering if you could replace that CRT tube inside of that iMac with a flat screen and still have it work. I know the bezel is rounded to handle the shape of the CRT, but it would be awesome to upgrade the CRT screen to a flat screen and still retain this form factor.

[@stevencarlson5422]

glad you fixed it and it didn't break apart its is a terrifying thing to do nowadays

[@ericwood3709]

I have that exact machine. And that exact problem. Not eager to attempt all that work on it, especially since I've never done a thing with solder.

[@reecepeart]

Thank you for pronouncing Bondi correctly!

[@alextirrellRI]

This is great to know. We have several old iMacs in storage and I know this is becoming an issue. I'm maybe more worried about the brittle internal frames at the moment -- I've seem some horror pictures on Facebook. Also, I have a Studio Display coming soon - I know this is an issue for them as well -- very curious if a reflow and grease job is all that will need as well?

[@brucesyvertsen2147]

That's a cool electric screwdriver you're using! Where is it available? Thanks.

[@rigues]

Had exactly the same problem on my Rev. B in 2003, had to send it to be serviced. Great little machine, my writing career started with an article about installing Linux on it. Sadly, the machine isn't working anymore since my cats dropped it from a table. The internal plastics cracked/shattered, but the external ones and monitor are fine. However, when I try to turn it on the power LED just stays orange, no chime. I'm hoping it is just a mistake I made when reassembling it, but currently I'm lacking the patience for a disassembly. And I do not have a good place for it, so I'm considering putting it up "for adoption". I had the box with the complete accessory kit (discs and manuals) until a few weeks ago, but this was on a shed that got damaged by a summer storm, and I had to throw the kit out. 😓

[@winstonsmith478]

Where did you get that electric screwdriver?

[@walterwhite1]

Great video pal 😍👍

[@DPfen]

If your mystery upgrade for the next video is a CPU/FireWire upgrade, I have that in a rev. A Bondi iMac that I acquired about a year and a half ago. 500 MHz G3 with FireWire port...but I had to remove the FireWire daughter card as it was causing the computer to slow to an unusable crawl for some reason and was unable to diagnose, so I will be curious to see if that is indeed the upgrade and if you were able to get it all working properly.

[@RetroPlus]

Mine does the exact same thing, i so wish i could use it as a monitor for my PC. It would be so sick.

[@philiphandforth4390]

I actually have my own shenanigans to look forward to. After watching your videos for a while I wanted to add a mac to my retro collection and decided to get an imac g3 and my luck so far has been....... Not good lol. The first one I bought I got delivered and the delivery company decided that it would benefit from a thorough kicking and the second one I bought went from fully functional to dead as a doornail in the space of a single car trip so yeah not a lot of luck on that front. My plan is to salvage both systems and Frankenstein together a functional one, wish me luck.

[@dmcintosh1967]

I have CTX monitor that I found at my grandad's in a barn. It was filthy but after a good cleaning it worked and had very sharp picture so it must not have been used much. The monitor worked for a while until the vertical drive IC got could solder joints. Which made the vertical almost collapse and lose sync signal. After I resolder the chip the monitor worked again just like it did when I got it.

[@chrismifsud7154]

I have a slot loading one and it does the same thing. Is the fix the same for mine too ?

[@m4rgin4l]

I freaking love this design language. The laptops in particular look amazing.

[@orincat10]

What's weird is that I got one a couple years ago with that issue and it went away after I started using it a little more.

[@guy_with_pants2742]

If you ever need, I've got a perfect low hour spare tube sitting in my storage unit only thing is it's got no deflection coils or neck board. Though I can't remember if it came out of a tray loader or slot loader

[@robert1975031]

yes have had to scrap one of these because the internal plastic had degraded so badly, it was like eggshells and cracked in multiple places. it makes me wonder if anyone has figured out a way to 3d print one of these frames.

[@jerrybomcool]

I’ve got one of these and after the bong it crackles like mad. Would this mean the fly back on mine is bad?

[@thomasb.900]

Love the Hoovie's Garage shirt !

[@DavideNastri]

I have the SAME PROBLEM! Then I tried a silent fan noctua mod and it did "tschh tscchhh tscchhh" 3 times and... Died. Where did you buy the extra flyback, if I can ask?

[@christopherdecorte1599]

Ouch first thought for me was flyback.

[@pud469]

Can you post a link to the source of the flyback???

[@FlightSimXtreem]

Okay okay, I subscribed. I liked it.

[@JaymeEduardo]

Replace the flyback, it will fail at some point and you will need to crack this thing open again. The more you open it , more those plastics get broken. Take extra care with the inside grey plastic that surrounds the CRT and with the CD faceplate in the front. You forgot to remove it before opening. I find it easier to always remove the it before opening it, less prone to break it. If the cd faceplate gets broken, you can 3dprint a support. I had to replace my imac flyback, back in 2018. It rocks till this day. Boots BSD with worspace manager from openstep. I wanted to compile the CDE manager into BSD. Someone did this in the ibook g3.

[@puciohenzap891]

Can you explain more about that dielectric grease? By the way - LMAO moment on 15:13. "Got 'em!"

[@myc0p]

Why did the electrical cords break up? There was no spark between them.

[@unfairlight]

I really love that Twiggy disk t-shirt.

[@marcinkowalczyk647]

@ActionRetro were you successful in fixing the industrial computer screen yet?

[@samueltoogood5703]

Looking forward to the psion IR shenanigans.

[@melphillips1608]

I def don’t miss these older models. Speaking from eye perspective!! Lol😂

[@JohnnyTheCache]

lots of retro stuff seems weird today. But this imac was already weird back then 😄

[@NaoPb]

I never knew there was actually a beige iMac inside one of those things. I kind of like the look of that.

[@radiosnmore]

this is awsome

[@Sucharek96]

Is this an ltt screw driver at 7:21?

[@DR.ELECTROHACKER]

My iMac g3 is stuck on Apple logo can you help me to fix it ?

[@touch_tone_telephone347]

I love when people talk about computers like they’re little animals. Its like damn, thats just a little guy

[@msthalamus2172]

I have the exact same problem on the exact same model iMac. :D

[@SianaGearz]

I have two of those Psion V i think. I got some heavy use out of them back in the day. After i got them used for cheap. I don't think i paid more than $50.

[@chrism869]

im dying in this heat during summer, my laptop is aswell, well i dont care ill sit here watch action retro

[@andresbravo2003]

It does have OS X. I was surprised to see it running on the first Gen iMac G3.

[@JoelRosenfeld]

I didn’t realize that it was that “easy” to get into the iMac. I have an old grey iMac SE that has been in a closet moving with me for the past 20 years. Might try breaking into it and replacing a startup battery that I suspect has been bad for a couple decades.

[@faenethlorhalien]

So it was basically a laptop with a CRT screen on it. Smart and bold for the 90s, tbh.

[@robertoguerra5375]

Nice 😊 I owned the same iMac 😊

[@TatsuZZmage]

i have a red late gen slot load one thats rusting. -_- so sad.

[@seratatu]

Please tell me that you discharge the crt off camera before disassembly 🙄🥶

[@TylerFurrison]

_zap, flicker_ damn it

[@GeFeldz]

Imagine making it easy to get to the safe part and hard to get to the "might kill you DED" part, mayhaps a thought or two behind that =D

[@dwarf365]

spoilers! A Sonnet Technologies HARMONi G3 upgrade. A 500mhz PowerPC 750 based G3 upgrade. I mean sure it's almost double the clock speed but the specs show it is only mac 8.1 to 8.3 compatible. I don't see any real world use for this other than "look at this thing". But 300 dollars back when it was new was an outrageous price and so is extremely rare. Glad you were able to fix the machine!

[@lukedavis436]

Fun fact.. With a lil modification you can apparently use a Rev A flyback in a slot loader

[@sjgrall]

@ActionRetro, where can we get that FileWare T-shirt?

[@ActionRetro]

I found it on RedBubble

[@infineon222]

the solder joint reflow is most likely what solved the problem, no?

[@koopytroopy-fc1iv]

I got a imac G3 but when u turn it on everything red but can be used still

[@koopytroopy-fc1iv]

If anyone knows what it could be please leave a reply

[@JB-mk4ry]

Sonnet Harmony G3 upgrade!

[@lindhartsen]

Was it any easier putting it back together? Or, I guess, movie magic could say it’s still apart with the end recorded out of the timeline.