0034 Replace those RIFA caps from your Apple II power supplies
![Adrian's Digital Basement ][](http://yt3.ggpht.com/ytc/AIdro_k7CrQRe71qN6c0Ua7A1P_I8KkxjqLa70u0zYeCvdvnKw=s48-c-k-c0x00ffffff-no-rj)
Вставка
- Опубліковано 15 жов 2024
- On today's SMMC, a lovely viewer has send in some Apple IIe parts from an old machine with a broken case. For testing, I want to replace the RIFA caps in the PSU to prevent the inevitable smoke show that will happen.
-- Video Links
Adrian's Digital Basement Merch store:
my-store-c82bd...
Support the channel on Patreon:
/ adriansdigitalbasement
Adrian's Digital Basement (Main Channel)
/ @adriansdigitalbasement
-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.co...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/i...
EEVBlog 121GW Multimeter:
www.eevblog.co...
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/i...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfrei...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/i...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/i...
Heat Sinks:
www.aliexpress...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/mis...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorec...
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino - Наука та технологія
Not sure if this was mentioned in the comments yet but those cable holders (not sure what they are called) just have to be turned about a quarter turn and the whole nut pops out of the metal case. Then they can be popped up to remove the cables without breaking the clamping part. It's really a whole lot easier than what you did fighting with it. This is how they put them in in the first place. The hole for the nut clamp is oval and the act of twisting it 1/4 turn locks or unlocks them.
No one cares guy in the comments, shut your mouth, Adrian isn’t going to acknowledge you. Your talking to the void, your a lolcow.
Due to your videos, Adrian, I was able to help someone who had a problem with one RIFA cap on his old Apple ][ just 2 or three days ago! His blew up and produced some smoke and smell! Hereby, I want to thank you for all your videos, which are a help even for novices like me!
Good to see Apple IIs getting some love.
The memory expansion on the original unenhanced //e works exactly the same as the enhanced //e. The enhancement kit just provides an updated firmware ROM, an updated character ROM (to add MouseText characters), and replaces the 6502 with a 65C02.
The 80-column hardware and firmware was on the motherboard, but the RAM it needed to operate was not (to keep costs down). The 80-column hardware needed Aux RAM to store the extra data. Apple made a few different cards for the Aux slot: a 1kb card mapped to the first text page (also usable for the rarely used double-low-res graphics mode, 16 colors at 80x20 with 4 lines of text, or 80x24 with no text) and a 64 KB "Extended 80 column card" that filled the whole Aux mode address space. On most //e motherboards the 64 KB card also enables double-high-res mode (560x192 monochrome, or 16 colors at 140x192). The very short-lived (and somewhat uncommon) motherboards with part number 820-0064-A are the only ones that don't support that mode; the revised 820-0064-B board and the later 820-0087-A board both support this mode. There are also third-party cards that allowed switching in even more banks of RAM.
The Platinum //e (with the revised motherboard that used higher density RAM chips and overall reduced part count, part number 607-0187-C or higher) shipped with an Extended 80-column card as standard. (Why not build it into the motherboard at that point? Probably so people could continue to use third-party cards that added more RAM without those boards needing to be redesigned. And in Europe a lot of video cards needed the Aux slot.)
The extended 80-column card that shipped standard with the platinum //e was compact and cost-reduced, just like the motherboard on that model. As far as I know all the Aux slot memory cards are compatible with all //e motherboards (aside from European video cards plug into slot 3 and the Aux slot at the same time, which need the Euro //e motherboard layout) but cards with 64 KB (or more) of RAM need to have a jumper moved or a trace cut to use them on the early 820-0064-A motherboard that didn't support double hi-res mode.
Exactly, the two types of 80-column-enabling cards were a separate concern from the "enhanced" IIe (which they all became later, from the factory) versus the original IIe. Back in the day, I saw and used unenhanced Apple IIes that were equipped from the start with the Extended 80-column card, which had the extra 64K.
Being enhanced is totally independent, and means that it has some of the additional features of the IIc, such as MouseText characters and the 65C02 CPU. Probably the most useful enhancements were bug fixes and other changes to the IIe ROM that actually improved compatibility with older software developed for the II and II+.
While we're on the subject, the enhancements, for many if not most people, are not very critical. When I got my IIe many years ago, it was unenhanced (but came with the Extended 80-column card), so one of the first things I did was purchase a vintage enhancement kit, which had never been opened and was still shrink-wrapped. I resolved not to install it until I felt it was necessary, however, and I still haven't opened it. 😄 Yeah, a couple of productivity software titles (the latest versions) that I never use anyway won't run (I could always run them on my IIc anyway), the latest ProDOS won't run, and some others have text-based menus that look strange without the MouseText (but are still perfectly usable), but the enhancement is not that big of a deal unless you really want to run something that requires it (in which case it is only the 65C02 CPU that is strictly required), and that isn't much.
Were do you source your Y-caps from? I do a Google search for y-capacitor Apple ][+, Apple IIgs, etc. the results come back with Rifa X2's! Possibly put a link(s) above with source(s) or part number(s)? Always enjoy your videos and learn quite a lot. Thanks!!
Note the RFI filter in the IEC socket also has between 3 and 5 RIFA capacitors inside the soldered case as well. They also will fail with time, and go bang and let the smoke out as well. Best to replace the filter with a new one as well, but as the Apple PSU already has filtering on the board, those class X and class Y Rifa capacitors, X between line and neutral, and Y between mains and ground, you can simply replace the socket with a standard input socket from any dead PC power supply.
The emissions testing for the power supply would have included both the encapsulated inlet filter and the onboard filter. The PSU will work without it but emissions may be out of spec. Admittedly it may be difficult (or impossible) to get an exact replacement but I would recommend replacing with as similar a part (Schaffner, etc) as can be found.
I know some filtered IEC sockets use RIFA caps inside, but are you sure this particular model has them?
@@mrnmrn1 If they are Schaeffner then they use RIFA inside. Most of the filtered sockets use RIFA, because they were, at least when new, the best filter capacitors rated for direct mains connection. Only after a decade or two of use do they have the high failure rate.
@@SeanBZA I would guess Japanese ones probably don't often use RIFAs. Seems like they were popular in Europe, but it's quite odd to me they were so popular in the US, too. What is even more odd, that they are still being made to this day! Not sure if RIFA still makes them, but WIMA surely does, with this same clear epoxy encapsulation. But why on Earth they still make them, as they are proven safety hazards after a few decades of use or just storage, and this is known for at least 30 years now? Polypropylene class X2 caps are much safer. I know these paper ones (initially, when they are new) have lower dissipation factors at higher frequencies, and maybe lower ESR as well, but with these known safety issues, they should be omitted. They even made class Y caps! I have a very old Sharp microwave which had RIFA caps both as X2 and Y caps in the input EMI filter (I think this Sharp microwave was assembled in Europe, Japanese made ones might use Japanese caps).
@@SeanBZA This is true. These RIFA caps are only potential failure hazards after decades of use, much as ordinary electrolytic capacitors are also. It is not meant to imply poor quality (like the Taiwanese cap situation from a few decades ago).
I had the rifa caps let go on a vintage phone system and it was a fairly simple replacement
I bought a Revox B126 CD player back in 2019. I took it home on a Sunday, plugged it in, and listened to some CDs. On Monday I went to work (naturally in those pre-COVID days), and came back home to a dead unit. The standy LED was off, and the player wouldn't turn on. After disassembling, I found out that the RIFA X cap has shorted, which took out the built-in fuse as well. In lieu of vent holes, the smell has remained inside, and waited for me to pop the cover :D Well, it wasn't a pleasant experience :)
I desoldered the cap, and put the player back together. It's still without that cap to this very day :) (btw, it has a standard PSU with standard linear regulators, no switchmode stuff in there, even though Revox has used a SM PSU back in 1984 in their B251 amp - could be the first in the audio industry?)
The extra LED on the mainboard is connected to the sound output. It lights up when the system is making a sound - however, it will only do so when no internal speaker is plugged...
I don't care what make or model of computer you drag onto the bench, your videos about it will be epic.
Greetings from the southern tundra! Just to be a little more accurate: I acquired an unenhanced A2E to scavenge the keyboard for my aging A2E with a few dead keys; it's really hard to program anything when the ")" doesn't work... I was able to get it cheap because it was unenhanced. I also managed to find one that matched my old machines key stems, which is apparently something you have to care about. I offered Adrian the leftover bits and bobs as you saw in the video and he didn't need the case (which was fine with me; the box size for shipping the case would have jumped my shipping cost enormously). I'm glad he can use the parts; they would just rot in my attic.
I have both the original Apple II and enhanced IIe. The Apple II's PS actually had no RFI caps on the input; you also had to drill out the rivets to get the case off the supply. I will be installing new Y safety caps in the IIe supply. Glad to hear you announce you're a ham during Bil Herd's video chat recently. 73 - Dino KLØS
Good to know. I need to take my Apple IIe's apart and remove those caps.
Im on my way to Adrians basement!! Wooo! I’ve got my sleeping bag, bottle of knock out pills, bottle of ghetto wisky and a pack of condemns. We are gonna sleep all night
Thank you for this. I've been meaning to power up my Apple //e at some point. This is something I should absolutely do.
Rifa caps have both X and Y ratings even though only X2 is printed on them. X-rating simply specifies they must not fail in a way that causes a fire, and Y-rating means they must not fail as a short circuit. Rifa's always fail open circuit so they meet the Y requirement.
Modern suppression caps will be rated for both X and Y class operation. Generally for line operation (covering EU/UK voltage of 230-250v) they should be X1Y2 rated... X2Y2 is also acceptable
Every capacitor will fail open with enough current.
@@pvc988 yes, but the safety rating means they shouldnt pass any current
Interesting, as always. I don't know if these caps age, but I remember my //e and playing with its mini-assembler, that was quite a few years ago !
My go to tool for those strain relief grommets are water pump pliers, specifically my Knipex Cobras.
7:40 1977 was perhaps ahead of its time for personal computers? But a north european manufacturer of home electronics that I happen to know well made TVs with switched mains power supplies from 1973 and onwards. (They actually started making computers as well, from 1978.)
I remember the story when "self healing" capacitors were introduced. They were meant for DC applications and the idea was that any pinhole fault in the insulator material caused a localized short circuit. The result was supposed to vaporize the very thin aluminum around the pinhole and clear the conductive path. However, it was only supposed to work on components and installations where the available energy was high enough and the resistance of the conductive layer also was high enough to generate the necessary heat. That in practice meant only metallized film, rather than metal foil type. Also, it turned out to be that it did not work with small capacitors, or assemblies where the surrounding components prevented sufficient contributing energy from helping the clearing operation. I myself developed a distaste for the whole self healing principle after some failures. And as to the X1 and Y2 capacitors, I prefer ceramic ones, just making sure there are no bending caused cracks around the leads. Any dry film, such as polyester is not suitable for full AC use due to something called partial discharge that commonly is called "corona", which destroys the chemistry of the insulator plastic.
That black tape on the 2 main filter caps is probably to help protect anyone working on it while it is open from contacting the rectified dc mains which in the US would be around 115V DC. I don’t know if that same model was supplied here in Australia, but if it was we’d be talking 338VDC instead. I don’t know if that was factory fitted or someone has added it later, but I’d leave it there if I were you.
I'm getting it. Mini mail call = around 30 minutes, super mini mail call = around 20 minutes 😁
Had the Oscillator in the PSU been a ROYER using a feedback coil connecting to the two base terminals with a 47K appling the bias and a 470PF across the driver coil and that should give a nice signwave and not a square wave.
For info, on most of the Apple ][ series PSUs the SMPS chopper frequency is between about 50khz and 80khz. Not sure about that model as I haven’t worked on one here, but I have worked on most other models for the Apple ][ plus through to the IIgs.
I think the tape on the two caps is to prevent the can from shorting to the chassis. Take an ohmmeter and measure from the can to either lead. You will usually see some measurable value of resistance, likely why higher voltage electrolytic capacitors are fully insulated.
Excellent video! The screen thingy that runs without a keyboard Is built-in diagnostics. If you will a RAM chip, or others, out your will get an error message.
5:25 the 80 columns card you have here only has 4K of SRAM so that only text mode was extended to 80col. It was sonly later that the more expensive 80col + 64K cards came out. It was only then that the enhanced IIe came out that managed to extend also the graphic modes with the double hires modes. The extended slot was aligned to SLOT-3 on the later models (the Chat Mauve EVA graphics card had to be put in slot-3 and in the 80-col slot).
I was watching I think it was gamers nexus touring a corsair power supply building and they were talking about the same stuff recently with corsair power supplies. Wow, I would not have expected it to be done back then.
RIFA Madness!
I dissent with the idea of foil being too low resistance and dumping it into the board. Current flows when it has a place to flow to. The idea of the foil is to give it no actual reason to go into the board. Aluminum foil is potentially even better than the mylar-foil bags except for being less convenient, or also when you have a battery - then the low resistance is bad because it would short the battery. That bubble wrap can generate static but what is that static voltage relative to and where will it flow?
If you're talking resistance to ground for anti-static products, then you do want to have resistance (like wrist straps are usually 1 to 10 megs) but when we're not talking actual ground, then a straight short is good, as long (again) as we are not shorting a battery.
Go experiment with a few sheets of bubble wrap that you tape some foil to and see if you get more or less static when rubbing the bubble wrap on itself when the foil is there.
Cool video! Always love Apple II content!!
Surprisingly I have never had a Rifa blow on any of my old machines - I think it might have something to do with the very dry climate around Calgary...
Where do you source your replacements from?
I should replace them just to be safe!
You can use any X2 (across the mains) or Y2 (mains to earth) capacitor. Preferrably polypropylene dielectric (MKP) instead of paper (paper will fail in the same way again) of a good brand. For example Wima, Vishay/Roederstein, Vihay/BC or Panasonic.
you're drinking the same adult beveridge as the last video :P.
RIFA MADNESS !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1
80 column card was an add on because of the cost of RAM in 1980 combined with backwards compatibility to the ][+
i have the IIE enhanced from 1986. it does have the rifas, the filter caps are in the iec power socket. (which i still changed) i see the one you have there also has the same power socket. maybe yours has been changed? if not i dont know why they would use that and the rifas
RIFA madness 👍
Can you post a link to the new caps?
Hi Adrian, Just wondering if you managed to remove the washer trapped under the sheet of insulation near the mounting stud. This is clearly visible in the video at time location 14:10, 15:33 just to the right of the soldering iron.
Great video .
The tape is to prevent the top of the case from touching the caps, right?
Correct, the can of the capacitor is actually connected to the negative lead often, and the primary side of a switching power supply is not isolated from mains, so if that where to touch the case there would be current flowing and maybe even sparks!
RIFA is becoming legendary, maybe keep the popped/unpopped Capacitors as investment😅. Just imagine how much you could brag in 2040: 'still having an unpopped RIFA duh, duuuude you sure?'
Could probably replace that weird integrated inlet with the capacitors with a standard IEC 60320 C14 inlet, and either have those caps on a breadboard, or just leave them out since it really seems like overkill? Altho i'm not an expert in AC filtering, but it really seems like it's excessive when the board also has those caps.
3:23 Yeah, MT RAM is notorious for being unreliable
But it has the apple logo! It's still unreliable, but it's more expensive!
It's a replace on sight type of thing, if you're already elbows-deep in a computer, might as well. There are still mountains of DRAMs out there to replace them with.
I remember Big Clive saying using aluminum foil to package ICs is fine.
I'm wondering if the Apple 2 graphics board was intended to be upgradable as time passed, but higher powered revisions weren't ever released.
I doubt that as the RAM refresh and the data being read out works hand in hand. This is an integral part of the Apple II hardware architecture.
While there were separate, enhanced graphics cards for the Apple II series (for example one with a TMS9918 chip) none came from Apple, AFAIK.
The only ones Apple distributed were RAM cards with either 1K (for allowing 80 column mode as shown here) or 64K RAM (which allowed for double hi-res graphics and other uses).
Well hello there Adrian. :D
Switching power supplies average 100 KHz.for operating frequency. The higher the frequency, the smaller the transformer core needed. Which is why switching power supplies have such small transformers. Nevertheless, that transformer is capable of supplying vast amounts of current.
Just switching from 60Hz to 400Hz allows you to reduce the amount of iron core in a transformer or motor by 80% and maintain the same power.
These days 1MHz+ switchers are a thing thanks to GaN FETs.
@@8BitNaptime Indeed, but I said "average".
I had these blow in 2 of my Apple II PSU's....
Nice. Those buns look yummy. :)
This might have been explained/told before, but what is the best replacement for those reefers?
Anything like a Kemet F863BC104M310ALW0L would be OK.
any 'suitable' capacitor that doesnt use a paper based dielectric , like the RIFAs do ! even new RIFAs are paper based according to datasheets
@@2dfx That was very specific. What exactly does one look for? What are these called?
@@andygozzo72 What does "suitable" mean in the common use cases of RIFAs?
@@Vermilicious class x/x2 or class y/y2 'safety' types, x/x2 for across mains y/y2 from mains pole to earth or unearthed exposed metal
The RIFAs have an aging problem: the case shrinks (hardnes out), developes small cracks and the isolating oil inside absorbs humidity from the air. After a while being turned off (!!) it has collected small waterdrops that settle between the layers inside. If an old device gets turned on after a long storage the voltage across the foils create a short from the water. That evaporates and the pressure causes the capacitor to break apart. If the fuse is strong enough to survive the initial short the isolating oil starts to boil and emmit an evil, stinking white smoke. Smells a lot like vinegar. I had quite a lot of them replaced with various 70s and 80s stereo gear.
My favourite example of a shot RIFA:
www.mcamafia.de/images/shot_cap_01.jpg
Thanks for sharing !
Thank you for sharing this information. I've had the argument with many and they didn't understand the microscopic cracks really did let in moisture. Just because they are Rifa's doesn't mean they are bad. They still make them. It has to do with age, use, heat, etc. Yes, the old ones need replaced for safety.
@@WC0125 The "burning Rifa" is particularly a problem with units that spend long time unused on a shelf. The shrinking and collecting humidity takes time and an unused capacitor *has* this time. Then - when the people think they should use the old gear once again - disaster strikes. Here in Germany there is an additional problem: the caps are rated 250V~ which nicely matches with 220V~ mains +10% tolerance. But in the meantime we got european normal mains voltage of 230V~ +10%, which exceeds the voltage rating. *And* if you apply 230V~ to a damaged Rifa you *surely* get a firework ... !
Be sure to replace with modern safety capacitors of the correct type and rating. Do not be tempted to omit them, as they do often serve a safety function as well as filtering. They need to be rated for the correct break down voltage too. Typically >1KV or 4KV depending on your local mains voltage and safety regulations - Do NOT be tempted to replace with non Type Y or Type X (depending on their function) capacitors, or a capacitor with insufficient breakdown voltage. You can have a very bad day if the AC mains starts leaking through to the low voltage DC side. Use a reputable supplier too, since the usual suspects will sell you any old junk and claim it is type X or type Y rated.
"Don't fear the RIFA".
I've had one of those blow in an old piece of test equipment, and the acrid smell was terrible.
Maybe a good idea is to put black duct tape over the shipping labels before turning the camera on, if you want to show the top of the box
It just occurred to me, is the MT of this DRAM the same MT as make MT32 microcontrollers? I suppose they are. Pretty neat
MT is Micron Technology.
I spy with my little eye some arnge Hazard Fraught pokey-pokey things!
😍😍 great Videos!!!
Would've integrating the 80 column ability affect software compatibility?
By 1984, the Apple //c had the built in Extended 80 column card, which added both the 80 column card and the extra 64k. In 1982, many Apple ][ plus system did not have a 80 column card, and there were several manufacturers. When Apple released the //e, you purchased the computer without the card, and then could add either the standard 80 column card for around $199, or the Extended for $249(?). Lots of stores bundled them in package deals. I sold Apple //e’s starting in 1984 and they still did not come with the card standard. When the //c came out, most //e’s were sold with the Extended 80 column card, but it was still in a separate box.
Primary puffer elco 320V in Eu
14:20 I wrote an email to you about those RIFA capacitors (you never replied). It could be that if the plastic cover is cracked they will not blow, but if they are not cracked they will.
Back in the 80s there was capacitors from a company called WIMA. When these capacitors have cracks they was safe to use, but if you found one that didn't have any cracks in the cover (shell) and you measured them they have always got short circuit. I suspect that this is the same with RIFA. I haven't got it verified about the RIFA's. This is only my own theory, so far.
My father has build his own heat regulation and he have RIFA capacitors from the 80s and they are totally cracked and they are working perfect.
I'm guessing that card is there because it was not possible to redesign the traces to accommodate more ICs. They just did a cut through of the bus there and added another card plane. In real computers, it would be a daughter board.
I never knew there was a tool for that grommet.. lol
Rifa caps are the bane of all electrical devices that have them, such a horrible stink when they drop their guts... :S
Cascade failure or Siskiyou failure? :)
put some volts thru the reefa :D.
Ah RIFA caps in old PSU's - always worth replacing... although being a bit of a butcher I tend to wait for them to go BANG! At least on BBC Micros the explosion is rarely terminal but often quite entertaining.
FWVLIW: Because my Apple II is stupidly upgraded I replaced the PSU's guts with a modern unit, added a -5v rail courtesy of an extra regulator, and transferred the wiring across ...along with an extra harness for direct power to the juicier cards to take some strain of the motherboard rails.
Some very old videos:
ua-cam.com/video/NBkmVyp7oI8/v-deo.html
ua-cam.com/video/_SH_62RPPYo/v-deo.html
Adrian, you need to watch more BigClive! Nearly all switch-mode power supplies, _especially_ modern ones, have large-value resistors (1Mohm is not uncommon) across the filter caps to avoid the exact zing you mention. Within two to three seconds of poweroff, it's no longer an issue. If you're at all curious about a given supply, just whack a multimeter across it no-load (or minimum load for those that absolutely have to have one for internal regulation) and see how long it takes to reach near 0v. This isn't rocket science, this is needless mystique.
The stuff about battery charging/discharging these days is honestly just as bad. Ugh.
I think he knows that. But:
1) Not ALL supplies have a discharge resistor.
2) It isn’t necessarily still there, connected on both ends, functional, etc.
3) The discharge time varies, so it’s not safe to assume that you can just flip the mains switch and immediately lay paws on the PCB.
Awareness and understanding of the risks is relevant. It’s not something that should stop any sentient person from working on their equipment, but it is probably rational to assume the primary side caps are loaded until you’ve verified they’re not. “Should” is not the same as “is” when it comes to safety. Things go wrong, and it only takes once...
@@nickwallette6201 Obviously all these points are correct. Since you seem to also have missed the fact that I covered them in my comment...
One, "Nearly all [...] _especially_ modern ones" -- older supplies, and some particularly awful nasty cheap things out of China, almost always (but not 100%) in things you shouldn't buy anyways, like dollar store iPhone chargers or other "too cheap to be good" electronics, sometimes skip the resistors. Sometimes. Usually even those have it!
Two, this should be self-evident, but if the discharge resistor (often also the fusible resistor acting as a fuse and as an inrush current limiter in modern eg "replacement power supplies" for laptops and such, which... generally aren't all that bad, actually, I've only had one system that was fussy about em) is burnt out or otherwise no longer functional, the power supply has far bigger issues as well, and the resistor in question really isn't your main concern. Most likely at that point what you're doing will be better termed a "post mortem investigation" rather than any sort of repair...
Three, although I've never seen one that took more than 5sec to clear itself out IIRC, as I said, if you're not sure, put a multimeter across it and watch it die as you disconnect power, with either no load, or in the case of early switchmode stuff such as this Apple II supply or early PC-XT supplies, the minimum load needed for the supply to self-regulate.
@@laserhawk64 Right. So.... what you're saying is, yes, you COULD have a PSU that has no discharge resistor, or it could have failed due to mechanical, electrical, or chemical issues, or it could take a non-zero period of time to discharge, and so a PSA to switching PSU newcomers is potentially valid... but... Adrian is still wrong?
No, man. I get that any reputable manufacturer SHOULD have installed a bleeder, it SHOULD be functional, and SHOULD drain the caps quickly. But that is not a given, especially when you're in a position where you need to pop the screws on a PSU anyway. Not everyone is replacing filter caps on a working unit. Sometimes you're getting in there to see what failed. It may be catastrophic and beyond repair, but you're not going to know that until you look. And it's ALWAYS wise to assume that HV parts are hazardous _until_ you've tested them or made them safe by shorting them, _which is what he said in the video._
I'm not one to advocate for cries of alarm that "OMG you're going to die instantly if you take the cover off a PSU or CRT!!!1!" but it's WELL worth a simple low-key notice informing newcomers, and reminding others, that there be dragons in there so keep your wits about you.
It wasn't over-the-top, it wasn't overly cautious misinformation. It was totally accurate and warranted.
@@nickwallette6201 No, what I'm saying is, you've very obviously failed to actually read what I'm writing. Twice, now.
@@laserhawk64 Yup. You're right. Calling the host out for not being educated enough, while also confirming all the reasons why his advice is perfectly valid.. that's all indicative of my cognitive inability, and thus worthy of the classic "you failed to read my post" argument. The last bastion of "I don't have a leg to stand on, but I'm going to argue anyway."
Well, it's been fun. I assume you'd like the last word, so feel free to leave your rebuttal after the beep.
yay 5th !!!! from the UK :D x
Your 7 days late kid
'old' RIFA class X/X2 and Y/Y2 caps wherever they are should be replaced, and ideally not with new RIFAs as they still make them with paper based dielectric!
they fail because the epoxy casing cracks letting moisture in ,making the paper dielectric slightly conductive , causing the heating and eventual destruction , they basically boil internally
„These are my strippers here…” - demonetized!
Note that anti-static and static shielding are two different types of products. The problem with using aluminum foil is that it's resistance is TOO LOW. That low resistance allows the full current of any static discharge to get dumped into a singular point and fry things even easier than when not using it. Never handle, wrap, or unwrap a foil wrapped board without a wrist strap (although living in Portland or Seattle is somewhat like always having a wrist strap on). If you can't use anti-static products, use paper to wrap the board followed by paper packing material, but a-stat packing materials are plentiful today. BTW: The Apple Service Technician training materials covered this point specifically back in the early 1990s.
Man those things freaking smell gawd awful when they blow.
I remeber AZTEC
You gotta hand it to Apple for using a switcher that early. Commodore and its clunky linear supplies ....
more to go wrong in a switching power supply
@@andygozzo72 Maybe with these early designs but in any case, these days they are decades beyond their service life, switching or not, parts fail. The Commodore power brick is notorious for failing even back then. When they designed the C128D Commodore finally wised up and used a switcher for the 5V, and those rarely fail. Granted there are fewer 128Ds out there. The SX-64 uses a clunky linear supply but with better design, but then you don't have enough current to reliably power a 1764.
And how about the 7805 and 7812 in the C64 running at nuclear temperatures, that's not good for reliability.
@@8BitNaptime the 'bricks' would rarely fail if soldered properly, i had a plus4 psu , seemingly 'dead', managed to open it, up and fault was obvious, pretty much every joint dry jointed, not enough solder, redid the lot and worked perfectly
you say about the 7805s running at high temperature, you should feel the 'chopper' transistor in a laptop psu brick then.......
@@andygozzo72 How do you propose "soldering properly" an epoxy-potted power brick like for the 64? And a bad solder joint doesn't mean that the linear brick is more reliable than a switcher. You're jumping around from one anecdote to another.
Notification Squad! :D
wish i could get me some of that Dave Plummer patreon cash
oh... my... god...
He wrapped it in tinfoil....
patrons scrolling up way too fast there !!!!!!!!!!!
is this a new style of video you're trying? it is way shorter than usual, way more focused on a single topic and there was way more jump cuts in the editing. while I, for one, watch your channel mostly for amusement - I like old electronics in general, but also the way you speak and the part of your personality you choose to show in your videos - I commend this new style, it is probably more educational and more compelling to the algorithm overlords.
The greyhounds he is drinking might have an effect.
Obligatory smoking RIFA is bad for you joke.