[YouTube] 8-bit Guy epic fail - Page 1
Forum section: electronics / general

author: WenkXue
author_rank: Newbie
timestamp: May 03, 2017, 09:40:41 pm
content: So this guy tried to use an Apple charger to power on the display.Waaa.....I think the floating ground of his Apple charger fried his computer.Is that right, guys?

author: ataradov
author_rank: Super Contributor
timestamp: May 03, 2017, 09:53:26 pm
content: Looks like just a faulty power supply. What it has to do with its ground floating?

author: Ampera
author_rank: Super Contributor
timestamp: May 03, 2017, 10:04:49 pm
content: Alright then.

author: helius
author_rank: Super Contributor
timestamp: May 03, 2017, 10:16:51 pm
content: Most switchers are smart enough to know that they have failed and disable the output. The 7805 in the C64's supply isn't and that is a common failure: the pass transistor gets shorted leaving the output unregulated.

author: MarkS
author_rank: Unknown
timestamp: May 03, 2017, 10:28:10 pm
content: Quote from: ataradov on May 03, 2017, 09:53:26 pmYes. Watch the video fully before criticizing someone.

author: FrankBuss
author_rank: Unknown
timestamp: May 03, 2017, 10:29:29 pm
content: Interesting that this 8 bit guy has as many Youtube subscribers as EEVblog, nearly half a million. BTW, this is the first part for the display:Very basic content and boring for me, but still 200k views and 18k likes? I could do this, too, but unfortunately everyone would complain about my German accent, and I'm not good on camera. Ok, so maybe I couldn't do it

author: ataradov
author_rank: Super Contributor
timestamp: May 03, 2017, 10:31:50 pm
content: Quote from: FrankBuss on May 03, 2017, 10:29:29 pmThis specific video (both of them) are very much offtopic for the channel. The rest of the videos are pretty entertaining to me personally. He also has 8-Bit Keys channel, all about old sound making devices.

author: helius
author_rank: Super Contributor
timestamp: May 03, 2017, 10:34:42 pm
content: Quote from: FrankBuss on May 03, 2017, 10:29:29 pmYou can definitely succeed on YouTube with a heavy German accent, like Flula Borg:9 million views

author: MarkS
author_rank: Unknown
timestamp: May 03, 2017, 10:35:33 pm
content: I would classify this video series as being targeted towards beginners.

author: FrankBuss
author_rank: Unknown
timestamp: May 03, 2017, 10:46:32 pm
content: Quote from: helius on May 03, 2017, 10:34:42 pmOMG, I guess I can't make such very stupid videos, so I will never get that much viewsQuote from: ataradov on May 03, 2017, 10:31:50 pmRight, I watched some other videos, very good quality with interviews (like in "The basics of BASIC", interviewing Ben Heck), good video editing, lots of content and good explanations. Of course, still boring for me, because I know most of this stuff already as an old C64 assembler programmer, but I subscribed to the channel now.

author: Ampera
author_rank: Super Contributor
timestamp: May 03, 2017, 11:02:40 pm
content: Okay, so I watched both videos, and I have no clue what the hell he is talking about. The OP somehow seems to think that the power from the LCD was frying the computer?Personally I have watched The 8-Bit Guy since he was called the iBook Guy (Ironically one of the first videos he put out after he switched names was about an iBook/MacBook) and I am kinda impressed at how well he understands electronics. Not sure why I thought he didn't understand it, I might be confusing him with Techmoan a bit.Even an uneducated fool like me can understand what happened in that video, and I see no way the LCD could have fried the C64. Even if power somehow leaked into the data pins, it's 5v, there is no way it could have fried anything, and if the ground was floating when the ground wire came loose, there shouldn't really have been any power doing much of anything on the screen.So, as mentioned,I think this may have something to do with this.

author: WenkXue
author_rank: Newbie
timestamp: May 03, 2017, 11:13:10 pm
content: Because the Apple charger has only two leads, it's not grounded, it may be possible that there is a great voltage potential between two power supplies.Remember that Commadore worked fine before he attached the LCD with the Apple charger, you are telling me that a power supply just suddenly failed for natural causes?Got flamed for posting for the first time, wow.

author: ataradov
author_rank: Super Contributor
timestamp: May 03, 2017, 11:21:59 pm
content: Both supplies would be isolated. Yes, their grounds will be totally independent, but it is not the reason for a failure like that.That lose ground wire may have shorted something, while it was lose, of course. So I don't think it was "natural", it was definitely due to connecting some random stuff to the computer, but I doubt it has anything to do with grounds.

author: HoracioDos
author_rank: Frequent Contributor
timestamp: May 03, 2017, 11:29:03 pm
content: Quote from: FrankBuss on May 03, 2017, 10:29:29 pmI will follow you. Go ahead! As a spanish speaker, we are used to watch almost everything in other languages (with or without accents)

author: MarkS
author_rank: Unknown
timestamp: May 03, 2017, 11:30:16 pm
content: Quote from: WenkXue on May 03, 2017, 11:13:10 pmYou got flamed for posting misinformation and slighting someone that actually knows what they are doing and did nothing wrong. If you had watched the whole video, you would have seen him find the source of the problem and correct it. You either ignored that part of the video and posted what you did here because you have a problem with him or you stopped the video shortly after the point where you thought you saw the error and posted here. Either way, we're not going to put up with that. That was your first post and not a particularly good start at that.

author: Ampera
author_rank: Super Contributor
timestamp: May 03, 2017, 11:49:53 pm
content: Quote from: WenkXue on May 03, 2017, 11:13:10 pmA. Power supplies are isolatedB. Even if there was leakage, it's 5v either endC. If this is the cause, it should be repeatable. He used another computer with an identical setup and it worked fine.D. It started before he hooked the LCDs up. He stated a voice synth module he was using even before all of this fried. This suggests that the power supply was sending spikes of current into the Commodore, enough to fry some stuff, but maybe not the actual computer until it did. There is no proof nor evidence to suggest that the separate power supplies and the floating ground had anything to do with the power supply failing. The power supply is completely separate, and unless there was some random surge of current from the Apple charger that went through whatever isolation was on the LCD, through the C64 without breaking it, and into the power supply, I see 0 reason why the LCD had anything to do with it, and as previously mentioned, this doesn't account for the busted voice synth cart.And the reason I pointed out the first post thing is that it's normally quite odd for someone to hop on the forum for the first time, complain about somebody, and leave little else. I apologize if you are a genuine first poster, and in that event, welcome to the forum, but we do occasionally get people joining the forum to rank on someone for some reason. I've seen it happen.

author: WenkXue
author_rank: Newbie
timestamp: May 04, 2017, 12:17:22 am
content: Quote from: TwoOfFive on May 03, 2017, 11:49:53 pm1.Oh my god, it's not 5V either end, a floating power supply could have tens or over a hundred volts floating upon contact with another power supply if the two power supply are isolated for some time.2.He used a newer model on the second try, it may have some bleed mechanism to deal with the floating voltage, or he connected the LCD before connecting the Apple charger, which could also solve the floating problem.3.Have you ever disconnected the metal bridge connecting the (-) and (Gnd) on your power supply and powered multiple devices with multiple isolated power supplies? Please try and probe those devices differentially, you will understand what I am saying.

author: MarkS
author_rank: Unknown
timestamp: May 04, 2017, 12:25:20 am
content: Regardless, you still did not pay attention to the video. He fried the first LCD by connecting its power connectors directly to the C64's port. By this time, the C64's power supply was already spiking and that killed the LCD. Not knowing this at the time, he then hooked up a second and then third LCD and used a secondary supply for these LCDs. This still had trouble, which led him to investigate further. It was during this investigation that he found the C64's power supply was damaged. The secondary supply was not the source of the problems he showed in the video. At worst, the secondary supply would have fried the third LCD; it did not.You are attacking someone that did nothing wrong. Get over it and move along. Post something productive.

author: FrankBuss
author_rank: Unknown
timestamp: May 04, 2017, 12:35:21 am
content: He didn't follow Dave's first commandment early enough: Thou shall check voltages!

author: MarkS
author_rank: Unknown
timestamp: May 04, 2017, 12:37:28 am
content: Quote from: FrankBuss on May 04, 2017, 12:35:21 amTrue, but the C64 runs off of 5 volts and it was operating normally at the time. He had no reason to doubt it. Lesson learned, I guess.

author: SL4P
author_rank: Super Contributor
timestamp: May 04, 2017, 12:55:51 am
content: Problem with a lot of online video journals is they are -made by - users - not developers/techs.They often have little or no idea of how the technology works or connects together - beyond the plugs described in the user manual.That's why we're here!

author: CJay
author_rank: Super Contributor
timestamp: May 04, 2017, 09:54:54 am
content: Quote from: MarkS on May 04, 2017, 12:37:28 amYebbut, after the first failure...Those PSUs are horrible and even back in the day they caused loads of problems, the first check whenever a C64 came for repair was the PSU voltages, casualties were usually the 906114 and/or the RAM.Hope he's learned a lesson, those chips aren't getting any easier to find

author: tooki
author_rank: Super Contributor
timestamp: May 08, 2017, 01:30:42 pm
content: Quote from: FrankBuss on May 03, 2017, 10:29:29 pmThe electronics YouTuber "GreatScott" is German but makes his videos in English, and they are great even with the accent! (I wish he'd spend more time on-camera... he's hot! 0:) )

author: SeanB
author_rank: Super Contributor
timestamp: May 08, 2017, 04:24:06 pm
content: I had a computer that had a failure of the 5V regulator, which then proceeded to put the full 16V unregulated rail into the computer for a few hours. It still worked fine, did all it was required to do but just had some odd behaviour, the self test never ran. Took the cover off, started checking power supply voltages on the test points. Start as usual from the bottom, -21V ok, -19V ok, -15V ok, -12V ok, 15V ok, then go to the 5V rail, and the meter did a range switch more than expected, I was expecting it to range from 1V to 10V, but it did 2 relay clicks. Shlumberger rack mounted meter, dating from the 1970's, and very loud relays ( but a lovely meter), and it was showing 16VDC on the 5V rail, not the expevted 5V1 or so it should be showing.Power off, and spent a while changing all the parts in the %v regulator circuit, from the pass transistors to the zener reference, including all the resistors, and the SCR crowbar that was not exactly working. then power up, 5v back to 5V, and it still had that odd power on self test issue. Go card hunting, and eventually saw the rather obvious failed IC, a SFC5403PM3 IC, which had delidded itself. Ironically, the 30V rated open collector IC was the only thing that failed running off 16V. New card, and it was fine again.Yes it did run the TTL off a 16V supply, cooking off the power in a massive heatsink block and the chassis, using a pair of beefy power transistors as pass elements, and this worked well.The other computer used a 28V supply, and had 2 SMPS units in it, one providing a constant 5V supply, using some BUX20 transistors as switches, and an air core inductor as buck inductance. Each supply was identical, just the one was switched off most of the time, being enabled only at the peak of the reference phase 400Hz to power the arithmetic logic, then being turned off to both save power and keep the computer power use under 500W, important in a shoe box that had over 5000 TTL IC's in it.

author: Zero999
author_rank: Super Contributor
timestamp: May 08, 2017, 06:45:50 pm
content: Quote from: MarkS on May 04, 2017, 12:37:28 amYes, the output even read close to 5V, when the IO pins were set to high.Actually could that have been a warning sign? Wouldn't 3.4V have been expected, rather than 5V, assuming it has a TTL output?Perhaps one of his next project could be an over-voltage crowbar? It doesn't need to be complicated. A thyristor plus the TL431 would do the trick.

author: metrologist
author_rank: Super Contributor
timestamp: May 08, 2017, 07:43:59 pm
content: You guys fooled me, I thought you were talking about this guy, and was ready to straighten you out that the 8-bit guy is someone different... Yeah, he's wen't a bit off his normal content paradigm, like taking his Chevy Volt to the drag strip...LoLF9IVtKa8C7Q

author: tooki
author_rank: Super Contributor
timestamp: May 09, 2017, 01:40:49 pm
content: Quote from: metrologist on May 08, 2017, 07:43:59 pm

author: P90
author_rank: Frequent Contributor
timestamp: May 18, 2017, 02:48:24 pm
content: Quote from: metrologist on May 08, 2017, 07:43:59 pmhe's wen't ?what the hell does that mean? LOL

author: metrologist
author_rank: Super Contributor
timestamp: May 18, 2017, 05:12:07 pm
content: Quote from: P90 on May 18, 2017, 02:48:24 pmIt means I was thinking of typinghe's gone...and ended up not completing the transition tohe went; and I think I had a few more ideas that got mixed into the editing.

author: janoc
author_rank: Super Contributor
timestamp: May 18, 2017, 10:26:53 pm
content: Quote from: WenkXue on May 04, 2017, 12:17:22 amYou do realize that when those two (isolated, floating) supplies are connected by only a single wire, then regardless of any hypothetical potential difference no current could flow and thus no damage to occur?Or rather the only current would be due to leakage through the Y capacitor in the Apple supply, which would be very tiny (otherwise you would could get electrocuted). The C64 supply is linear, fully isolated with a transformer and no suppression caps, so unless the trafo is defective, no leakage current across it. So such current would have nowhere to go.And once he reconnected the grounds, there was no more chance for hundreds of volts anywhere, because the two supplies stopped floating relative to each other.The only thing that Apple charger could have potentially caused, depending on the C64 power supply design, is that the 7805 regulator in it could die because it has been back powered (he turned on the display power before powering up the computer).However, that was unlikely the issue because he had problems even before he was playing with the displays and chargers (you didn't watch the entire video, did you?).And yes, voltage regulators do die. I had that happen in a power supply for my ZX Spectrum clone - also a 7805. Those 8bit computers took quite a bit of current and it was common that these regulators ran hot (in my case regulating from 12V down to 5V, so some 6W power loss) and were dying from time to time.Also Dave has a repair video or two where he is replacing blown regulators.Quote from: WenkXue on May 04, 2017, 12:17:22 amThat "floating problem" is a complete red herring.