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One insidious thing about ESD damage, is that it can be a slow progressive failure. An IC can look fine today, tomorrow, and next month, but then over the course of multiple months or years it'll start acting all fucky and weird. I'm currently trying to fix a Colecovision. It has worked before, though with plenty of glitches i thought was caused by bad contacts with the cartridge (it was vibration sensitive). Left it in a drawer for 3 years, now i bought a new PSU so i could make it 'nice' but it broke while not doing anything. The old computer guys say it's likely the static ram chips that are dead. It doesn't draw anything on screen. Not even garbage data, so they reckon the CPU crashes due to the SRAM not giving it sensible data. I'm gonna work through the service manual (it has one, complete with oscillograms of what to expect at the various data lines!) and see if i can figure out the problem.
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Mar 6, 2023 17:14
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Many years ago at work, our team finally got our hands on the really expensive (~$10K) video capture/editing card we'd been waiting for. It was a new design from the hardware division, and there weren't that many in existence yet. When it arrived, we all stood around the boss as he held the card and gave a basic overview of the hardware layout. I had a question about something and said "Oh, so does that mean that this chip here--" and reached in to point it out with my finger... and very clearly felt a big static ZAP from my finger to the board. Of course I was certain that I'd just carelessly destroyed a piece of equipment that was worth about twelve of my car and would take months to replace and I was going to be fired and blacklisted and I'd have to go live under a bridge with my shame. But when we plugged it in, it worked perfectly. And it continued to work perfectly for years.
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Mar 6, 2023 18:13
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Sweevo posted:You don't destroy chips by touching them Lmaok.
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Mar 6, 2023 18:45
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I have absolutely hosed up some IC components via ESD while handling them outside of a safe environment during demonstrations. Stuff like my finger zap causing a resistive touchscreen to wig out and require power cycling to fully killing it once. I’ve never noticeably messed something up at home though by just discharging on something safe and not rolling about on carpet or something.
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Mar 6, 2023 20:26
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I believe CMOS chips are more sensitive to it. I always ground myself when opening up my C64, because they’re not making any new SIDs and I’m not taking any chances.
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Mar 6, 2023 21:23
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AFAIK the big ESD worry came about after the late 70's and into the 80's when people started using a lot of 4000 series logic. The story I've heard is that the original CMOS 4000 series was extremely static sensitive, either lacking or having very under-designed protection circuitry, which led to significant real-world failure rates. What came before, e.g. the bipolar 74/54 logic families or even discrete transistor circuitry are basically impossible to damage with ESD. So the consumer electronics industry almost definitely had terrible ESD practices when NMOS/CMOS entered the market. Modern ICs are generally well protected, but it's one of those things we're never getting rid of since it's basically the "a wizard did it" of the electronics industry. It's basically impossible to prove or disprove ESD damage.
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Mar 6, 2023 22:51
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I will continue to laugh at people on hobby forums and in youtube comments making GBS threads themselves because someone didn't wear a wrist strap when handling a resistor.
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Mar 6, 2023 23:48
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Sweevo posted:I will continue to laugh at people on hobby forums and in youtube comments making GBS threads themselves because someone didn't wear a wrist strap when handling a resistor.
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Mar 6, 2023 23:53
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Sweevo posted:I will continue to laugh at people on hobby forums and in youtube comments making GBS threads themselves because someone didn't wear a 22 long range rifle when ordering a subway sandwich.
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Mar 7, 2023 00:09
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3D Megadoodoo posted:Does he still refuse to wear a grounding bracelet, thus destroying every chip he touches with his Electro-finger and wondering "how on earth this chip is now dead, too?!?"? Im sure it was him that brought it up and I think he wears it around his ankle?
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Mar 7, 2023 02:57
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Humphreys posted:Im sure it was him that brought it up and I think he wears it around his ankle? Yeah, I’m pretty sure he wears one around his ankle to keep his hands free.
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Mar 7, 2023 03:00
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3D Megadoodoo posted:I just remembered the video where Curious Marc zaps the ROM of his first computer, by delicately touching it. But then he just makes another one. CuriousMarc is insane about replacing capacitors. Like never even mention the possibility a capacitor is bad and needs to be replaced unless you want to hear a rant about it
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Mar 7, 2023 03:08
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computer stuff can be more robust than we imagine. one time a kid poured orange juice into my pc. video card and optical drive got most of it. cleaned them off, video card got contact cleaner and some brushing, both worked afterwards. i still use the optical. it has some trouble ejecting, annoyingly, but otherwise fine.
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Mar 7, 2023 04:55
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I guess I can also add that I've never lived in a house with properly grounded outlets. Sometimes just not connected to anything, sometimes a hosed up bootleg ground.
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Mar 7, 2023 06:16
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For ESD stuff, being at exactly ground potential isn't the most important thing. The bonding of potentials between you, the things you're working on and your work bench is what's important. You could probably get away with putting an anti-ESD mat on your desk, connecting your wrist strap to the desk, and putting all your sensitive stuff on the mat while it's still in the antistatic bags/foam. That way, no dastardly electrons will jump between your fingers and the sensitive pins of whatever ancient IC you're working with, because they've already figured out where to go via the outside of those antistatic bags, via the anti ESD mat etc etc.  You can get away with a LOT with modern stuff, but not with the old stuff.
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Mar 7, 2023 08:10
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I should have broken a LOT of electronics as my homelab is carpeted, and I often play with ungrounded stuff without ESD protection (and most of the time sweaty due to the Aussie summer heat)
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Mar 7, 2023 08:34
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yeah any old/discrete cmos stuff is sensitive, and any one-of-one prototype stuff you should be extra careful with, but anything else is just whatever. none of the repair professionals i know ever do more than just occasionally touch a grounded surface to discharge any accumulation unless it's one of the above cases
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Mar 7, 2023 08:50
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I've killed exactly one thing with ESD, my old GeForce 7300. And I don't regret it, because I picked up a Radeon 3870HD for a song that weekend, and it was very nice having the previous generation's top of the line card for once (this would have been when the GeForce 8000 series/Radeon 4000HD series was new.)
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Mar 7, 2023 08:56
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I never take too many precautions with brand new stuff from big suppliers with easy returns because if it doesn't work once it's installed it obviously came broken from the factory, not my fault never had any problems other than two different sticks of ram at different times and those might have genuinely just not worked right out of the box old/precious stuff I will touch a grounded surface first, maybe think about what surface I'm working on/what I'm wearing
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Mar 7, 2023 09:06
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I've never really bothered with an anti-static strap. I usually earth myself out on a computer case or a tap before doing any hardware work. Been doing it for well over 20 years, both building new computers and repairing old stuff and never had an issue
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Mar 7, 2023 11:30
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Same, my kitchen bench doubles as my work space, so a grounded water pipe is never far away.
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Mar 7, 2023 11:44
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BattleMaster posted:CuriousMarc is insane about replacing capacitors. Like never even mention the possibility a capacitor is bad and needs to be replaced unless you want to hear a rant about it He's kinda right though. People have latched onto this idea that all old capacitors are bad and need replacing asap, almost to the point of magical thinking. That isn't how you should be troubleshooting things, and might even introduce new faults - which isn't what you want if you don't even know why the thing wasn't working in the first place. e: This is especially the case when dealing with analogue stuff like he often does. Say you find a fault in some complex feedback network that takes the output out of spec. You blindly change every capacitor in the machine and the problem goes away. Have you fixed it? Or have you covered up the real problem and you might not find out until much later when you discover you can't calibrate the circuit properly or it now misbehaves in other ways. Sweevo has a new favorite as of 15:32 on Mar 7, 2023 |
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Mar 7, 2023 12:31
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Yeah I have to agree with that. It’s wild to hear people say he went on an insane rant about capacitors. Almost everything the guy does is super methodical. That said, I remember the “rant” video and it was a little jarring because he had always seemed above caring what people said in the comments, at least to me. But to call it insane is way too far imo Let’s not forget that this is the guy who spent like an hour of his life disassembling and cleaning a dip switch for his printer. He has a thing for original parts and half the stuff he comes across is super rare or impossible to find original parts for. If something isn’t bad by any measurement you take, why replace it? In conclusion, he has his team of super smart guys, tons of equipment and resources, and goes around fixing old computer stuff… that’s why I hate him so very much 
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Mar 7, 2023 14:54
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I can understand people getting into the mindset of just replacing all capacitors they come across I mean for my grandfather they were his number one most hated component throughout his career as an electrical engineer and I'm sure most of us here still remember how bad the capacitor plague was. I think the real answer here though is to just totally ignore the endless moronic droning of youtube commenters. coldpudding has a new favorite as of 16:29 on Mar 7, 2023 |
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Mar 7, 2023 16:05
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I collect vintage macs. Replacing caps is step 2 (removing batteries is step 1) for almost anything I buy. I also totally understand the “I have it apart, I should recap it now” mindset. But there is definitely a ‘magic fix’ mythos about recapping. Especially around CRTs.
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Mar 7, 2023 16:54
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It doesn't help that in order to test a cap you need remove it from circuit, which is half the step to recapping anyway. Recapping is fine and all I just question a person's troubleshooting and EE skills when it's the first thing they go for.
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Mar 7, 2023 17:22
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There's a lot of nuance to capacitor stuff. Paper capacitors need to be swapped, without exception, if you want a reliable device. If they're interference or snubber capacitors, they *will* blow up and smell up your room for multiple days. I did some temperature-resistance measurements of a Rifa. At room temperature? 50 Mohm, lovely but won't blow up. Heated up to 65 degrees (very much possible on a hot day in a hot PSU) it dropped to 2Mohm. Eventually it'll self-heat and blow up. Vintage macs often have Rifa interference suppression caps, and they will blow up sooner or later. But you don't do all electrolytics, right? In tube equipment a faulty paper anode decoupling cap can roast a much more expensive output transformer. The DC blocking cap can absolutely murder both output transformer and output tube. I've had dozens of tube radios on my work bench. The number of radios with paper caps that did *not* need the DC blocking cap swapped, is 2. Two. So these specific caps should be swapped on sight because of the bad consequences. If you don't require top notch reliability, you can leave the rest of the caps in place if you only turn it on 15 minutes, once or twice a month. But otherwise, sooner or later due to the effects of heat cycling, the remaining caps will start leaking worse and worse till they go short or in thermal runaway. And even then, some brands of capacitor (especially british ones covered in yellow wax) are just SO bad that the device won't work at all or just make odd noises. I learned my lesson. Left some Philips tar coated paper caps in place in a professional radio receiver. Worked fine for a few years, after like 3 years of regular use one still decided to short out. No damage because the power rail it was connected to, had a high series resistance. Ended up removing the last of them straight away. Now, electrolytics are a category of their own. They are not bad by default. But there are radical differences between brands. Philips brand high voltage ones in their post-1955 tube radios are excellent, outperforming even some new ones when it comes to leakage. And i've found a Tesla brand from the 1940s in a cardboard cylinder which also is still up to spec. But without exception they have to be re-formed and measured if they're good. I only swap around half of the high voltage caps i encounter. Low voltage in transistor stuff? Big PSU smoothing caps are almost always good, and if they're bad you'll quickly hear/measure it as hum/ripple on a power rail. Small ones? Often there are multiple types of cap in a device. Test one or two of each color/brand. If the samples test bad, replace all of the same type. Because often if one goes bad, the rest will soon follow. Recapping itself carries a risk. Quite a few people have damaged boards, forgot what to put where, lifted tracks etc. So if the sample tested capacitors are good, leave them in place. I guess recapping is popular because it doesn't require any thinking.
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Mar 7, 2023 17:26
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Light Gun Man posted:computer stuff can be more robust than we imagine. one time a kid poured orange juice into my pc. video card and optical drive got most of it. cleaned them off, video card got contact cleaner and some brushing, both worked afterwards. i still use the optical. it has some trouble ejecting, annoyingly, but otherwise fine. I dumped an entire mug of hot tea with lots of sugar into a desktop form factor computer with the case off on the floor that was running at the time. It immediately blue screened. I retrieved the mug and just shut the computer off in absolute disgust with myself. About 2 months later I took it all apart and literally rinsed the motherboard off thoroughly in a hot shower. I then left it to sit to fully dry for several more months. Put it back together and it ran for years.
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Mar 7, 2023 20:51
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TheMadMilkman posted:I collect vintage macs. You can’t just say this and not post pics
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Mar 7, 2023 21:44
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TheMadMilkman posted:I collect vintage macs. Replacing caps is step 2 (removing batteries is step 1) for almost anything I buy. I also collect vintage macs and follow the same steps as you. The caps aren’t always the fault, but replacing the caps that are 100% always leaking their poo poo all over the board with tantalums that won’t ever leak is the only kind of “future-proofing” that actually works. Edit: posting pic 
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Mar 8, 2023 01:45
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GutBomb posted:I also collect vintage macs and follow the same steps as you. The caps aren’t always the fault, but replacing the caps that are 100% always leaking their poo poo all over the board with tantalums that won’t ever leak is the only kind of “future-proofing” that actually works. Are those eMacs at the bottom there? I always found those a pain to work on, particularly compared to the similar-looking G3 iMacs. The iLamps were hands-down the worst, though.
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Mar 8, 2023 01:52
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That loving skull
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Mar 8, 2023 02:28
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AlternateAccount posted:I dumped an entire mug of hot tea with lots of sugar into a desktop form factor computer with the case off on the floor that was running at the time. It immediately blue screened. I retrieved the mug and just shut the computer off in absolute disgust with myself. drat how many of us have had liquid incidents with computers? do we need a gang tag? (no) that's bonkers though, glad it worked.
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Mar 8, 2023 08:55
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Data Graham posted:That loving skull Haha the skull is an anatomically accurate 3d printed skull with magnets holding the various parts together that my 6 year old wanted. It’s glow in the dark and she named it Agent Skully. CaptainSarcastic posted:Are those eMacs at the bottom there? I always found those a pain to work on, particularly compared to the similar-looking G3 iMacs. They are eMacs and they have a lot of steps to disassemble. The PSU always needs a recap because they leak like crazy and ruin things, and the earlier ones can be overclocked quite easily by bridging some pads on the logic board. The CRTs are really nice, but their main purpose here is that they are so heavy they keep the shelf from falling down. GutBomb has a new favorite as of 13:08 on Mar 8, 2023 |
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Mar 8, 2023 13:05
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CaptainSarcastic posted:Are those eMacs at the bottom there? I always found those a pain to work on, particularly compared to the similar-looking G3 iMacs. Those Lamps were complete assholes to work on. Also that cable going to the display being a cause for concern and a full strip down required.
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Mar 8, 2023 14:03
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GutBomb posted:I also collect vintage macs and follow the same steps as you. The caps aren’t always the fault, but replacing the caps that are 100% always leaking their poo poo all over the board with tantalums that won’t ever leak is the only kind of “future-proofing” that actually works. Wait, you actually put tantalums INTO the vintage stuff you’re repairing? Aren’t Tantalum capacitors the “fail short and explode” ones? I’ve seen a lot of vids replacing tantalums with electrolytics in places that don’t specifically require Tantalum characteristics supposedly because electrolytics don’t usually fail short and destroy things. I’m sure you know what you’re doing, but I don’t get it
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Mar 8, 2023 15:14
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GutBomb posted:I also collect vintage macs and follow the same steps as you. The caps aren’t always the fault, but replacing the caps that are 100% always leaking their poo poo all over the board with tantalums that won’t ever leak is the only kind of “future-proofing” that actually works. Finally, someone to pester about why my Intel Mac Mini circa 2007 just stopped starting entirely after being unplugged and moved
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Mar 8, 2023 17:01
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Rev. Bleech_ posted:Finally, someone to pester about why my Intel Mac Mini circa 2007 just stopped starting entirely after being unplugged and moved You didn’t wear an ESD strap.
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Mar 8, 2023 18:14
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Arivia posted:You didn’t wear an ESD strap. goddammit
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Mar 9, 2023 00:55
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namlosh posted:Wait, you actually put tantalums INTO the vintage stuff you’re repairing? Aren’t Tantalum capacitors the “fail short and explode” ones? I’ve seen a lot of vids replacing tantalums with electrolytics in places that don’t specifically require Tantalum characteristics supposedly because electrolytics don’t usually fail short and destroy things. When tantalums pop they pop in a visually spectacular way, but they generally only take themselves out, and it’s a pretty rare failure. Electrolytics sitting there for years doing nothing WILL leak and eat the board, which is a far more common outcome than a blown tantalum. It’s a pretty common thing in retro mac circles to replace surface mount electrolytics with tantalums. edit: Higher end macs like the Quadra 650 came with tantalums from the factory. GutBomb has a new favorite as of 02:07 on Mar 9, 2023 |
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Mar 9, 2023 01:49
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