Dammit - Page 1
Forum section: electronics / general

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:08:22 am
content: I just lost half of a tutorial I spent almost three hours writing - when I clicked "Post" I was taken to an empty "Start new topic" form. I then found I was unable to go "back" to any earlier version of my post either - I had previewed it several times without issue, but now it seems at least the first half of what I'd written is irretrievably gone (I had to separate into two post due to photo sizes, and I have a copy of the text for the second half). Worst thing is, I don't know if I can be bothered to do it all again from scratchHere's a photo of the result - if there's any interest I might find the energy & motivation to (re)elaborate.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:11:44 am
content: Reserved

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 04:14:30 am
content: I guess the moral of the story is to either prepare it offline, in a word processor or text editor or something.Alternatively, you can (every 15 minutes, for a long report/post), copy (ALL the page), then paste into a word processor or text editor. Where it will be save-able.I've lost tons of forum posts. E.g. I spend 15 minutes preparing the post. It is all ready, just one quick google search. I find the info, then close that window. Then notice I just closed the WRONG window, and the window with the post has VANISHED forever.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 04:18:28 am
content: Quote from: Lomax on March 07, 2016, 04:08:22 amIs it some kind of bench power supply, and you are doing something to the backlights for some reason ?I can't fathom out, why one is VERY bright, and the other is dim/black.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:21:49 am
content: Use a separate editor. I like markdown editors. Unfortunately this forum does not support markdown.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:22:24 am
content: Quote from: MK14 on March 07, 2016, 04:14:30 amI usually do this, but the EEVBlog forum has a generously sized text entry box, and it provides shortcuts for inserting markup which is handy. I also (incorrectly it turns out) assumed that previewing the post would create an entry in the browser history that I could go back to. Lazy, I know, but I just wanted to post it so I could go to bed!Quote from: MK14 on March 07, 2016, 04:14:30 amI'm pretty sure that if it is a normal form post (not encrypted) you can go back to it even after closing the tab/window - in Firefox at least. It appears there's some Javascript doo-daa going on when you post here on EEVBlog though - nothing is added to the browser history

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:26:30 am
content: Quote from: MK14 on March 07, 2016, 04:18:28 amYeah, it's one that doesn't have any backlights at all, and ridiculously hard to read as a consequence. The tutorial was a step-by-step for how to retrofit LED backlight panels.Quote from: MK14 on March 07, 2016, 04:18:28 amIt's to show what it looks like pre/post the mod - the LCD on the left is original, the one on the right has been fitted with a backlight. The dark picture at the bottom is what it looks like when only my desk light is lit. Unreadable without the backlight.

author: Muttley Snickers
author_rank: Unknown
timestamp: March 07, 2016, 04:27:41 am
content: This looks like it would have been a very interesting thread, a damn shame really......Want some real nightmares try posting from an LG Smart TV, misspelled words, dropped text, cant copy and paste links or post pictures, three paragraphs in and the browser drops out, forever going back for an edit to fix something that was or wasn't there beforehand and I seem to fall for it regularly and have now learnt for larger posts to prepare it in MS Word offline on the computer and then copy, paste and a final tweak as previously mentioned, works every time.I do hope you find the energy to complete this thread at some point, it does appear to be a nice project.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 04:29:04 am
content: Quote from: Lomax on March 07, 2016, 04:22:24 amI think on THIS forum, you could well be right. But it was other forum(s), whereby, essentially if you lose the page (and/or move away), you lose it forever.I think on some forums, you can even delete the page (close), and yet still go back to it (if I remember correctly). They may even periodically say "page saved", every 5 minutes or so.It is VERY annoying, losing a massive post like that.But when it happens, I usually recreate it as best I can, immediately. Or after a bit of a sulk!

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:30:52 am
content: Quote from: HAL-42b on March 07, 2016, 04:21:49 amMarkdown +1 It should be standard, really.

author: tautech
author_rank: Super Contributor
timestamp: March 07, 2016, 04:34:02 am
content: I'venormallybeen able to find them in my browser history, but not always.Big, involved, important post, prepare it offline is best advice.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 04:38:12 am
content: Quote from: Lomax on March 07, 2016, 04:26:30 amI've got some older, somewhat many digit, multimeter(s), bench. Apparently they have a common fault, whereby the mains input filter goes bad (with age).The interesting articles (I've NOT done these steps yet, but might in the future), show how to put in a new/fresh mains input/socket/filter AND (possibly different articles involved), replace the aging dim yellow? led backlight, with modern led(s). The improvement (from pictures I've seen), is rather big.I.e. it goes from somewhat very dim (a bit like your pictures), to very pleasantly bright. Because it is a bench instrument(s). There are no batteries to save, so a good backlight makes lots of sense.In principle I like the backlights on modern handheld multimeters, but hate the fact that I've heard that they automatically switch off after about 10 .. 30 seconds.I would HATE that. Sadly I don't know of any handheld multimeters, which can permanently leave the backlight on. I don't care about the batteries, because I can just change (or recharge them), more frequently as necessary.I'm looking forward to the day when we probably will get, commonplace, low cost oled multimeters (handheld), which effectively have the "backlight" (not needed with oled), ON all the time. Since oled characters glow, by default.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:49:32 am
content: Quote from: MK14 on March 07, 2016, 04:38:12 amMy Fluke 117 leaves the backlight on permanently if you turn it on while holding the backlight button down.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:53:27 am
content: Quote from: MK14 on March 07, 2016, 04:38:12 amI love OLEDs, but what about day/sun-light readability? For all their flaws its hard to beat the daylight contrast of a monochrome LCD - only EP-displays are better here, but those are obviously useless for multimeters (and AFAIK impossible to backlight). That was part of why I thought it worth-while writing up a guide to the mod I did to that PSU; daylight readability remains excellent despite the changes.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 05:28:34 am
content: Quote from: Lomax on March 07, 2016, 04:49:32 amThanks!That is VERY useful to know. At some point I'm going to be on the market, for a multimeter, with definitive high voltage fusing (as demonstrated/discussed by Dave on many videos).I DON'T work on very high voltage electrical distribution systems etc.BUT there is always the danger that there can be confusion.E.g. Someone is helping out at some electronics something or other, at work/exhibition/gathering/hobby/friends etc.Mistakes/accidents can happen.The Fluke 117 looks very interesting.Quote from: Lomax on March 07, 2016, 04:53:27 amI had NOT thought of that, day/sun-light light reading. A very good point.Early LCD equipment, from ages ago, had that problem. I remember lots of LCD stuff, was unreadable in direct sun-light. Mabe it was a backlit type, I can't accurately remember.It's sort of crazy that we have so much technology at our fingertips. Supercomputers (of 10..20 years ago), for $10. Automatic self-driving cars, at some point in the future. etc etc.But we CAN'T get somewhat cheap, (very) high quality displays yet (hand held). (High end mobile phones are rather expensive, and use up fair amounts of electricity/battery, and they are not perfect).I guess one day they will crack it. PaperInk (or whatever brand name you prefer), for handheld book readers, looked promising. But that also seems to be falling out of favor.I guess multimeter, backlit displays are NOT too bad, and have quite good display lifetimes (on the battery).

author: m98
author_rank: Frequent Contributor
timestamp: March 07, 2016, 10:54:42 am
content: Similar thing happened once to me, then I installed the plugin "Lazarus: Form Recovery".

author: Stupid Beard
author_rank: Regular Contributor
timestamp: March 07, 2016, 11:10:58 am
content: Quote from: MK14 on March 07, 2016, 04:38:12 amSolartron?The yellow LEDs on those meters are not dim due to aging so much as they're just from a time when yellow LEDs were really dim. I've been meaning to change the LEDs on mine for ages, but have been unable to decide on a colour. It's a little bit tempting to use RGB LEDs for a laugh.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 01:38:34 pm
content: Quote from: MK14 on March 07, 2016, 05:28:34 amIndeed. It's a bit gimmicky perhaps, but the 117 does have built in non-contact high voltage detection. "Volt Alert" they call it, and it works from a distance, flashing and beeping when 110/240/380VAC is present (I don't think it will detect HVDC). Just beware that all the Flukes in that series (114/115/116/117) have been made in China, and are not quite up to the standard one might be used to from Fluke. For one thing, the viewing angles on the display arepretty bad.Daylight readable LCD displays that also have a backlight are known as "transflective". They havea special reflective layerbehind the LCD which is not completely opaque, thus allowing light from the backlight through. These films are ridiculously expensive, costing as much as £60 ($85) for a single 17"x17" sheet (minimum quantity 10 sheets!). Some high-end smartphones have started using these (Samsung, Apple?) which is quite welcome, though colour displays don't work nearly as well in this mode as monochrome LCDs do. Displays with dedicated segments also offer contrast and sharpness advantages over pixel-based ones, where the "screen-door" becomes a factor.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:28:12 pm
content: Quote from: MK14 on March 07, 2016, 05:28:34 amThat's what I meant with "EP displays" - the tech is based on "electrophoresis". They're great for things like books, and only consume power when the displayed image is changed, resulting inextremelylow power use. Two big drawbacks prevent their use in multimeters though: they cannot (AFAIK) be backlit (though there are "front-lit" e-readers available), and the redraw speed is much too slow (on the order of a single fps!) - anything that changes rapidly becomes an illegible smudge.

author: TheSteve
author_rank: Unknown
timestamp: March 07, 2016, 06:09:14 pm
content: I've had the same problem with the forum the last few days. I haven't lost any detailed posts though. Also had the forum crap out when sending a PM.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 07:16:54 pm
content: Quote from: Muttley Snickers on March 07, 2016, 04:27:41 amYour wish is my command:Fiat Lux: retrofitting LED backlight to unlit LCD displays

author: Artlav
author_rank: Frequent Contributor
timestamp: March 07, 2016, 07:39:11 pm
content: Such things happen sometimes, at various places and for various reasons.I kind of got into a habit to copy whatever i was about to post before posting.Usually it's Ctrl+A to select all then Ctrl+C to copy it, Ctrl+V to paste it back as verification of the action having taken place.Happens more or less automatically by now, and i advice to get a habit like that.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 08:14:51 pm
content: Quote from: Lomax on March 07, 2016, 01:38:34 pmWow £60. But I do appreciate that some things are EXTREMELY expensive to manufacture and/or design.I much prefer to buy the "REAL"/genuine item, if that makes sense.E.g. If it was a Sony TV. I would avoid the low end/cheap ones, which are widely rumored to NOT be made by Sony, but instead, contracted out to a cheap Chinese manufacturer. Which I would NOT want to touch with a barge pole.i.e. My experience of stuff like that (cheap, Chinese branded stuff), is that as soon as you take it home the picture quality looks like I've made a big mistake, and the remote control and plastics of it, feel cheap etc.Then (ironically to my delight, because I can go out and buy a proper (although expensive one), without feeling guilty), about 2 years later, it blows up and explodes, or refuses to switch back on from standby etc.I'd probably go and buy the "proper" ones.BUT. That would be my one and only "main" multimeter. For any others (I have lying around, to check resistor values, battery voltages etc, i.e. no mains or high voltage or serious work), it looks like I can get a proper, high voltage fused multimeter, for about the £35 level. By carefully shopping around, for the known to be good (high voltage fuse) rated ones. Or a Bryman (From TME), for not that much more (£50..£59?, for the low end models).tl;drI had a bad near miss with a very high voltage accident (myself), which I am embarrassed about. Very fortunately I was NOT hurt, but it has taught me that these high voltage multimeters, are probably very important. Because you never know when such an unexpected incident is going to happen.I was repairing a somewhat old oscilloscope (crt type). I managed to connect up (unintentionally), to the very high voltages inside it (despite trying to be very careful), which destroyed the scope AND test equipment, which I had just connected up to it, to help fix it.I was probably standing well back from it (just in case), before switching the set up on (I connected it all up, while powered off). Which probably helped save me from a terrible shock or worse.tl;drAny cheap multimeters connected to that setup, at best would have also been destroyed, but could have exploded (from what people say and youtube videos I have watched). In practice, I'm NOT sure if the voltages in an old scope are powerful enough (current wise), to do that. But they would be likely to be destroyed.That scope (Hitachi 20MHz, low end) and (to me), a rather expensive power supply (Dual LCD, 30V/2.5A, approx, fully linear), were somewhat badly taken out. I managed to repair the PSU (pair of 2N3055's in the output stage, one had gone short circuit, probably saving the rest of the PSU from being destroyed).I'm also especially skillful, at accidentally leaving meter(s) configured for current measurement, then trying to measure a voltage, by connecting it directly to a high current PSU. Fortunately at the moment, it is just cheap, glass fuses, I blow.Quote from: Lomax on March 07, 2016, 04:28:12 pmIt's sad really, because I hear that they have got very good contrast and are very readable, even in poor lighting conditions. I've NOT got any, and only very rarely seen them, myself.It's a pity that ten years ago (approx), they could not develop them to have a much faster update rate, practical backlight/sidelight and maybe even colour and more pixels. I guess some things are technically possible and/or affordable and/or paid for by the market, and others aren't. So they sometimes disappear entirely, eventually.E.g. Nixie tubes anyone ?You seem to know a lot about modern display technologies. I am also fascinated by them. LEDs have become so amazingly cheap now. Something crazy like less than $0.01 each in quantity, for a somewhat decent white led (for home lighting etc). So presumably sooner or later, whether it ends up being OLED or something else, LED. We hopefully will see mini-breakthroughs in display technology.I don't know if you have seen it. By MikesElectricStuff is this new type of interesting (at least to me), display technology. I won't spoil the video, and tell you about it here. But sadly, I wanted to buy/play with them, they are extremely expensive (or too small, if you buy a cheap one).

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 08:16:13 pm
content: Quote from: Stupid Beard on March 07, 2016, 11:10:58 amExactly right. There was a big sale off of them some time ago, and many were available on ebay at quite keen prices. So I managed to get into them/buy them.My major priority is the possible problems with aging input filters (etc), on some/all of those meters. But it makes sense to update the backlight at the same time.But it is one of those projects for a VERY rainy Sunday, which never seems to come up!6.5 digits (if I remember correctly), is still VERY competitive and expensive. Although I often DON'T need such potential accuracy, the resolution, allowing very slow capacitor/voltage changes to be observed, I find very preferable to 3.5 digit (COMMON!) multimeters.

author: Lomax
author_rank: Frequent Contributor
timestamp: March 07, 2016, 10:33:40 pm
content: Quote from: MK14 on March 07, 2016, 08:14:51 pmThat's probably the thing that pisses me off the most about Fluke outsourcing their manufacturing to China; although the jobs are now performed by low-wage slave labour in some anonymous factory city, they still charge a premium for their product. Since their production costs are now pretty much the same as any other Asian manufacturer, you gotta ask yourself what it is that you're paying for. Everyone's doing this though - when Dr Martens moved their manufacturing to the Philippines, and from there to China, did their boots become any cheaper? NOT ONE PENNY. The only result was fewer jobs in Britain, higher shareholder dividends (temporarily), and lower quality footwear. And a sour taste in my mouth. I now only buy second-hand Docs, "made in England".Quote from: MK14 on March 07, 2016, 08:14:51 pmYeah, I had read about those somewhere, including an explanation on how they work (IIRC they're based on a repolarisation effect similar to how LCDs work), but I hadn't seen them on video before - thanks for linking it in! Definitely interesting tech, particularly as it's flexible and uses virtually no power at all; 4uA @ 5V! Can they be backlit though? If not, they're still cool, but a much less interesting display technology I think!One type of display that works reasonably well in both bright sunlight and complete darkness are EL panels - I don't mean EL backlit LCDs here, but display panels where each pixel is an individual EL emitter. These produce extremely high NITS (if needed), remaining easily viewable under all conditions from all angles, and have much better refresh rates than EP displays. They're a big favourite in the space, military and medical tech sectors, where lives may depend on being able to read a display quickly and correctly. Unfortunately, they have several major drawbacks; they tend to be amber on black monochrome, suffer from horrible burn-in, have comparatively short life-spans (fading in brightness over time) - and finally, they come with an astounding price tag, to match the expensive gear they're usually found in (you know, like theOV-104). No really; even a dinky 320x240 specimen will set you backat least$600, a more usable 640x480 close to $2000. I STILL WANT ONE THOUGH. You can find themused on eBay at affordable-ish prices, but the burn-in turns me off.