Fix this part before it KILLS your vintage computer!
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- Опубликовано: 3 дек 2024
- Replacing the capacitors on motherboards is something vintage computer enthusiasts are all too familiar with -- but that's only part of the problem.
CayMac Vintage tweet about Mac IIsi modern replacement PSU: / 1703878219244396815
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Glad to see the hot tweezers put to use. Soldering equipment quickly pays for itself!
Better than blowing the SMD parts all over the place with a hot air gun.
I never tire of watching you work on vintage computers.
Try swapping the daughter board in the second psu to prove its that. If so it should not be too difficult to knock up a replacement.
Glad you saved one from scrap. To everyone else involved into this kind of repair: always wear your safety goggles, it's about the electrolyte trapped between the PCB and the conformal coating, it tends to pop when heated right onto your face.
Traces with heavy black bubbling still eating into the copper substrate must be scratched to remove the coating and the remaining still active electrolyte, brought back to bare copper, from there one can decide to keep it that way, use bodge wire or recoat it.
There's just something about those IIsi power supplies. The few I've opened up are always a horrible mess on the underside. I'm glad you got one working! I'd agree with your assumption that the little daughter board is causing the trouble on the other one. Thanks for the video!
Could be many things I’ve found. Diodes go bad, there’s a resistor that takes a beating. I personally hate the iisi psu
I've only installed a capacitor backwards once, and funny enough, it was on a IIsi power supply. I knew instantly what I'd done when I powered it on and it went "POP!"
Once i was messing with old pcs, (win98), don't know what I've done wrong, just remember the cloud of white smoke coming out of that pc LOL i was quick to disconnect it from the power at least.
I did the same thing on a Mac Classic analog board, it's tough to keep track of which + sign is for which cap on the silkscreen when they're so bunched up. Powered it up and saw it inflate, caught it before it popped though😅
Really interesting video! Always cool to see vintage tech getting fixed up and acting like it was brand new
Well produced and informative as usual. Thanks.
Great episode as always. That corrosion looked pretty gnarly!
That little daughterboard is extremely easy to fix. But if you send it to me I will make a 1:1 identical re-production and mount all the parts onto it and send it back to you. Assuming it works you can get a batch of PCBs made and move all the parts over to a new PCB if you come across another corroded board in the future.
One more thing to try on the dead supply: check the double rectifier diodes on the secondary side (in the TO220 packages). I fixed a IIci power supply with the same issue after finding a shorted rectifier - standby voltage was there but would not power on. These IIsi power supplies look like a really similar design.
Definitely a good suggestion.
The only visual inspection, frequently, is not enough, and starting measuring components it's the key to grasp what's broken or out of spec. Having, moreover, schematics of the board could be a game changer, especially for test points or reference voltages.
holy... new videos from this does not compute, computer clan, and technology connections all in one day? i'm gonna have a good night
Thanks for gifting that special Mac clone to Action Retro. I'll watch your videos twice as hard, use Premium, and even consider the Patreon, although there's only so many creators I can support at the same time.
Nice vid (again). Did you try a working daughterboard on the last PSU? Just to make sure it's daughterboard is broken?
Did you try placing the child board from the working psu to check if that's the culprit?
Glad to see custom made alternatives because I'm afraid of working with power supplies
capacitors measuring 'slightly' high is not normally a problem, older ones sometimes had a very wide tolerance, especially positive, as much as +80% in some cases...
The daughterboard is quite small.
Wouldn't it be possible to recreate a new PCB? Or would that be too difficult?
That daughterboard looks like it only got one layer and the layout is pretty simple. Someone could def recreate it very easily.
@@matchc0635 probably, if all parts are removed it could be scanned ...
@@andygozzo72 Scanned like with a regular scanner?
@@peddersoldchap yeah, could try...but would have to remove everything so you could get if 'flat' to the scanner plate
@@andygozzo72 What I mean is, the scanning is done with a regular scanner, right? Or is it done with a special scanner for PCB's?
I picked up a non-working IIsi during COVID for really cheap to work on as a project. I remember pulling the PSU out and while holding it tilted it literally started to leak green goop. Also came out from underneath the power connector on the logic board once I pulled it out of the case. Probably one of the worst PSUs I had to work on so far (the Mac Classic analogue board was a close second though cap leakage/corrosion wise and I heard the IIci ones aren't much better). Lots of cap juice, lots of fish smell, all drenched in old flux, and the daughter board took a heavy hit as well. Got it all working perfectly but definitely not for the faint of heart (or for people with a sensitive nose or who can't deal with the "ick" factor these PSUs can have haha).
Repairing that daughter board is so easy and simple.
Just mark and measure every part then take all of rhem off. Scan it and drop it in your computer. Trace the pcb out with your favourite pcb making tool. Order from jlc pcb some new replacement and swap all the components over onto the new pcb.
Thats a single sided board. It should take about an hour or 2 to do all this and totally worth it.
Thank you for your videos, have a merry christmas and a happy new year.
This reminds me that I need to improve my soldering skills to remove or replace the clock capacitor on my old XBOX. Also to remove some components of other boards to have spare parts.
Not familiar with Macs, but I think the reason PSUs are overlooked is that they have the potential to absolutely wreck hardware and very few people are comfortable enough in their skills to work on them. I have a few AT and proprietary form factor PSUs lying around, but I feel it's safer to buy high quality modern PSUs and use adapters.
I have an Apple IIGS, after using it for about 30 minutes, one of the rifa caps blew up, it smelled disgusting. I decided to replace all of the capacitors and it works great, it should last another 36 years.
The RIFAs going is quite normal on old machines and nothing to worry about really. Removing them and not replacing them is generally fine. The case on them tends to crack and eventually gives off the magic smoke.
Once i managed to blow a capacitor from a phone charger, dude the smell was terrible lol
@@6581punk those epoxy cased RIFAS should always be replaced on sight, especially if signs of cracking as moisture gets in, they use a paper based dielectric which absorbs moisture, some at least of their 'new' types are still paper based according to datasheet, i dunno if i'd trust them!! hopefully they're improved....
Love that subtle disclaimer, about how you shouldn't work on a PSU if you're not comfortable; I feel the same way (one old PSU is not worth your life). I've repaired more than a dozen PSU's, its shame that last one didn't work.
Great content!
I love electrical work especially on old stuff😊👍🏻
The measurement of capacitance is spurious on cap going bad because of leakage. The meter ends up having to dump more energy into the cap, since the cap turns it into heat, and this thermal loss and thus effective charge dumped into it ends up being misregistered as capacitance.
Get yourself LCR T4, the famous $7 PCB, or any of its upgraded derivatives, doesn't matter, they have enclosed ones, colour screen ones, etc. Its ESR measurements are pretty wildly off (but are comparable relative to each other, so you still can tell bad caps from the good), BUT it won't confuse leakage for capacity and it is capable of measuring leakage rate. Your meter can attempt to measure in circuit - T4 can't, it won't be able to decide what to measure, but you're taking the caps out anyway! It's great for PSU repairs in general because it'll take just about every single 2- or 3-legged component and tell you whether it looks OK.
I think the eaten away daughterboard calls for a PCB project so you can print a new one by a prototype house. You can then repopulate the fresh PCB with original components. I also can't say i terribly mind doing tedious restorations like that by hand, i can also just make new copper by hand, but i'm sure it's too much effort for many.
Thank you for this video. I feel like a major problem my G3 AIO and VAIO Desktop have these exact issues.
Finally, some good equipment for soldering.
This is the BEST video you ever made.
Nice work and video. I have a IIsi and it has an Aztec (sp?) PSU that seems ok. It is rivited together and so I have not opened it yet. I see Apple used Sony and other brands I wonder are certain brands more prone to failing or leaking caps? The one on my LC III for instance, was not leaking the last time I checked it. I do have replacement caps for it and I think it is time to recap them all. This new PSU replacement looks like it will be great.
“No! This does not compute!” Said the robot from 2013
This is why I hate these dedicated power supplies for old Apple computers, because they’re hard to repair and you’re better off replacing them with something more modern for power supplies!
no need to 'replace' if they can be serviced..
@@andygozzo72 if they can be serviced, that’s good! But most people and those places don’t fix old Apple computers, particularly Macintosh II which is rare, and the original parts from the power supply made in 1987 is too expensive.
@@Markimark151 i doubt any of the 'custom' parts like the inductors would be bad, most likely caps or semiconductors..
@@andygozzo72 rather get new caps with the new power supply. Apple made their computers to be planned obsolescence, that’s why I don’t trust Apple with their built quality anymore.
@@Markimark151 Criminy. This era of computer was never intended to last 30+ years, and yet they do. But it wasn't Apple making the PSU anyway, unless you missed the giant Sony logo. Capacitors go bad. That's not "planned obsolescence," that's just nature taking its course.
It's like complaining that Ford designed your car to fail when you don't replace the oil or transmission fluid. Things require maintenance because nothing lasts forever. Learn to solder a few caps, and maybe the odd diode, and those PSUs will keep going until the materials decay beyond salvage.
I doubt you'll get the same lifespan out of the supplies made today, with their razor-thin margins, and notable Japanese capacitor vendors dropping products from their portfolio by the dozen due to competition with the "manufacturers" who use strings of random consonants as names.
Could you swap out the good daughter board from first PS you got going with second to confirm thats the problem? If so , you could spend a hour or so checking continuity and running wires. Probably not as corroded even if looks bad. Small board so worth doing?
@5:56 which liquid is inside?
Although I am not an owner of vintage PC hardware, I am currently battling a Playstation 2 PS and can't seem to win, lol. I get good capacitance on the AC side and then bad on the DC. Any way, I clicked of course as I love your vids. As per, this was a great one!
Daughter board PCB seems like easy to make a replacement for, if that's the only issue.
Small, single layer. Might not even need a rerouting if you only need 1 and can edit the scan/photo into a high contrast mask.
It’s not. I’ve already made the pcb for one but a lot of the components aren’t known. So I never even produced it
@@AmigaofRochester ok, but at least it can be used if you can transplant the components from the old one? (A lot of soldering though)
@@killymxi I have never had the daughter board be straight bad. Always soldering. I just fix the soldering. I remove the chip, clean pads sometimes sand them, clean the chip up and replace. I personally hate iisi psus as they’re not very good in general
Pretty crazy old caps can be recharged and will work good as new again. Way above my paygrade though, and the same for screwing around in a PSU 😅
yep, aka 'reforming' but thats only if theyre pretty much good internally anyway, the oxide film degrades over a very long time if unused and first power up can result in a high charging current, best done gradually with current limiting
Did you check the relay? Any power on any of the power rails?
I find it very funny that you and I are working on the same thing right now. I repaired my IIsi power supply recently and it still doesn’t work 😡.
Wish I had real time to take PCs laptops apart, test, troubleshoot, and repair them!
I never use OG psus anymore.
Not only are they more dangerous with age but less efficient in comparison to modern stuff.
I always convert to ATX in some way that is reversible however.... for the "serial number" folks...
no need to 'never' use an old one, they may be perfectly ok and/or easily serviceable, i have many AT psus still good, less so ATX ones, they seem to have suffered from the 'capacitor plague' a lot , as for 'less efficient', theyre still switch mode and newer ones work pretty much the same way, with 2 transistor 'totem pole' drive to the main transformer
@@andygozzo72 Nearly everything in my fleet is running its original supply. I pretty much always start by disassembling the PSU, cleaning everything really well, replace the caps (because you'll need to eventually anyway), replace the fan with something adequate (don't just throw a Noctua in everything), and test with a dummy load.
The ONE time I skipped the cap replacement, it failed within a year, and almost took the motherboard with it.
I have had one supply fail after cap replacement, and I didn't figure out what had happened to it. I decided to replace it with something else of-era, because it was kinda cheap anyway. I also had one (on a PS/1) that required replacing the DC-side rectifier diodes. Seems to be a common fault. Works great now though.
Learn to maintain these things and you'll be far better off.
the C64 community knows this very well. use something else than your precious vintage computer to test old grungy psu!!!!!
yep make a test load rig 😉
Hard to fault the manufacturers...after all no one expected anyone to still care about these 30+ years later.
I have an Apple IIc and yet to get a power supply to power it on. Are ethereal any caps or certain parts known to fail on those models? I examined the board and nothing seemed bulging or corroded.
Were the 2 caps behind the daughterboard replaced? And the little ones on the hot side?
Do you wanna hear my project list of this week:
1. RGBI to VGA adapter for my commodore 128
2. RGB scart cable for my amstrad CPC6128
3. Fixing my sinclair zx spectrum+
Isn't possible to make a replacement of the tiny PCB and "print it" on "PCB Way" or some service and use the caps etc. from the original in the new one? I know is a TON of work, I'm just wondering if it's possible like in other type of things.
Merci pour le partage 🙂
Likely the second one needs the daughter board rebuilt. I usually remove a lot of those components, clean the pads and resolder them.
I am wondering if you ever try to fix your computer blindfolded? Make it more challenging
I wonder of you could gen up a replacement board and have it created by PCBWay or one of the other board manufacturers?
What are you using in the ultrasonic cleaner?
Ultrasonics, of course. :-)
You didnt prove why the second psu wasn't working. You could have pulled the dotter board from the first repaired unit and put it in the second psu to see if that fixed it. Also the dotter board being only single sided replacing parts and jumping traces wouldn't have been impossible. If you were inclined you could have had a new board made up and transferred the main control chip to it with new parts. Tho i understand thats more time consuming for a PSU that ultimately costs less then 100$ to find another spare. Its a idea tho :0
Some stones on someone willing to put a known defective PSU in their vintage computer :P I hope you knew at least some idea of the errors, because sometimes things just break so that no protect mode will save you and everything just gets fried. Highly suggest to always check the voltages first if that's possible.
Just replaced some caps on a failed monitor power supply and it came back to life.
Wouldn’t this daughter board be swappable from one of a working PSU? If that worked perhaps there is a way to re-engineer just the daughter board.
nice video. you have enough parts where you can swap out the psu and daughter boards if you really want to know what is bad.
in regards to that daughter board, all those corroded traces would need to be gone over with a fiberglass pen to remove the solder mask and corrosion, after that you'd be better off using ohm mode to see if any are high resistance/open etc and then repair/re-tin them using some copper braid that's had fresh solder soaked up on it (GadgetUK has a great youtube channel where hes demonstrated how to do this many times on vintage computers).
while there was some moderate trace corrosion on it, it certainly could be fixed by someone willing to spend the time doing so.
any corrosion on any pcb trace will fail at some point so its always best to deal with it rather then ignore...
Also while im not sure how common those daughter boards fail, it would be quite easy and trivial to just design a replacement pcb for it (assuming you or someone you know has basic CAD design skills). while im all for modern PSU replacements and use some myself on different retro machines, getting a batch of replacement daughter board pcb's made would cost maybe $1 per board in batches of 5+ rather then the expected cost of a complete modern PSU will cost.
Lastly its probably worth mentioning that the average person shouldn't really be opening and working on any PSU's if they don't actually understand the potential risks of electric shock. there's often 1-2 very high voltage Capacitors on the primary side that store about 400v (or more), generally a good PSU will have a bleed resistor connected to those to discharge then when turned of but not always and sometimes its failed. probably just worth mentioning that next time you do any PSU videos. or at least letting people know to short out those caps with a 1M resistor to ground and then use a multimeter to check its voltage has discharged before working on it. that 400v can stop you heart and in extreme cases kill a person so please just be careful when working on them.
Guess this explains why my IIsi doesn't even attempt to power up anymore, and hasn't for over a decade. By the time I gwt some time to look for cap damage, it will be ruined if not already I'm sadly guessing.
Bueno una victoria al 50%, definitivamente es algo positivo 😊.
Good boy! Clean off that flux!
VERY GOOD ADVICE REPLACE ALL CAPS 🧢 😊😊😊
You're a culprit. FOR ELECTROBOOM!
I think modern replacement PSU is the way to go (save picture of old board and leave inside). It will keep the computer running healthy, and not risk doing unrepairable damage to motherboard. Plus, newer PSUs put off less heat, and dirty voltages, that would have shortened life of other parts. To preserve history, some times requires hard choices. Thank you for sharing this video.🎬👍
Love these, but wish the videos weren't short-- 8 minutes is not enough time lol
i try to use solid state caps when i can, as they cant leak but otherwise good video
do not assume polarity markings on pcbs are correct, it has been known for them to be printed wrong, double check how its connected in the circuit!
Yep. Get in the habit of checking what the PCB says to how the original part was installed. I have run across a few that were backwards, intentionally. Not many, but more than none.
@@nickwallette6201 yep, dont go 100% about what any print says on the top side, especially if originals appear to be fitted wrongly, check how its actually wired on the track side, such as make sure negative of cap goes to ground if its for a positive supply rail, or positive of cap fed from the cathode of an output rectifying diode, etc.
End part revealed what I've been wondering. Why even try to rescue old powersupplies? First of all they're usually awfully inefficient, like I used c64 power supply as feet warmer in cold winter days. Just ditch them as they're... power supplies and have nothing interesting to even salvage for old hardware. Just re-use old casing if needed for aesthetics, though I wouldn't care if modern replacement would be thrown inside old computer.
I also like modern replacements on older machines, but not every person like it.
no theyre not 'awful' or 'inefficient' ..as for the c64 psu issue, its likely just dry joints on the 3 terminal regulator as i found in my plus4 'wedge' psu, if you can open it up and get to the track side, resolder everything and it'll likely be perfectly ok, fit a 1N5339 zener across the 5v out to clamp any overvoltage if it occurs...
@@andygozzo72 lol it was new back then. Efficiency is absolutely horrible on older hardware. They all were like that
They're not "all" like that. The C64 is a really shoddy supply. That's Commodore for ya. That was an era where you might find a few exceptions, like linear supplies and such. But generally, if it's a switch-mode supply, it's reasonably efficient, and should be reliable as long as you replace any capacitors that are prone to failure. (The old 80s ones are pretty stout, but I replace them anyway.)
@@nickwallette6201 interesting that every single person I know has stated the exact same thing and it's c64 supplies were like toasters. And again it wasn't age issue back then.
I know I'm in the minority but it would be cool if you made longer videos; these are over almost as soon as they start.
Funny how a polarity sensitive componens get installed backwards.... after 20 years in electronics - not uncommon
the second power supply still seems fixable to me.
the daughter board looks easy to replicate maybe a pcb specialist can replicate it
You recapped your own stuff, yet STILL blew new components? Dude that's what you get. YOU'RE LUCKY!
Finally fixing psu
The Power issue might be good enough.
You can make a new pcb from jlc or pcb way. clean with a glass fiber scratch brush the oxidized pins and transplant the components to the new one. I think the original pcb is good, the electrolite attacs the top laquer most of the times, is the oxidation who created bad solder joints. Original is better than those chinese junk
And if it ain't broke, don't fix it...
Still a good result, corrosion is a b*tch.
GET A NEW DAUGHTER BOARD FIXED
my mom said to never do that!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
capacitors
Voice sounds different
yeah try to get or make a PSU tester bad way to fry a working Main board..
PSU repairs may be dangerous and should be done only by those who know what they are doing. If you are not sure, just buy a new one.
⚠ Don't poke around inside of PSUs unless you know what you're doing. There could be high voltages inside, even with the power cord unplugged.
While a little pre-game knowledge and caution is warranted, I would advise people to learn and proceed rather than get into a chicken-and-egg situation of "if you don't know, don't touch it" because then you won't learn, and you'll _never_ know.
Pretty much all of us that have ever touched screwdriver to electronics has discharged a cap with our finger at least once. It's an educational experience.
Technically high voltage doesn't start until 2,500 Volts. What you can encounter in a PSU is only peak line voltage. Or in the US double that. That's what the 110/220 switch does, it's a voltage doubler. Now CRTs can contain lethal potentials. There you might want to proceed with caution.
Great video as usual. If anyone is looking for someone to help with their iisi, I offer rebuild services. I sometimes can resurrect dead psus but they are a bit of a pain at times.
Imagine pronouncing IIsi "twoosey".
2ussy
You never really proved that the daughter board was preventing the PS from starting up.
maybe didnt have a spare
He had the one from the working PS lol. @@imantsvolkovs2447
Make sure it's plugged in while you work on it, so your multimeter actually measures accurate readings only. ALWAYS work on a power supply, especially since the Capacitors will definitely not kill you. (sarcasm, don't follow this guys' advice. Or else, you might die.)
Buy an external PSU. Easy to fix and replace
888th Viewer
Please learn how to use the word "ironically" properly.
You probably meant "coincidentally".
Should you be doing this. Its so dangerous playing with a psu
Only dangerous when you have no clue what you are doing. I recapped a BBC Micro PSU and a Vectrex. Took all the precautions needed, especially on the Vectrex CRT.
@@6581punk its not a job anyone not trained should do
@@hoztravels2024Pipe down, baby.
@@hoztravels2024 Nobody is born trained. Study. Learn. Then DO. Otherwise it _will_ fail.
@@nickwallette6201 my point is you shouldnt touch a PSU unless you know what your doing. Feel free if you want to but know the risk