Tell us about yourself!

Complete Your Profile
  • When did that happen?I agree, that does now work, but this is the first time I've been aware of it working. Maybe I'm not normally logged in?If you don't want it to show all steps for those who are not logged in, the post about adding #anchortag to the URL for step 2 should work - if you put a HTML anchor tag on step two.

    View Topic »
  • I agree, Michael. I've often thought the same thing. The only work around I've come up with is to click the little (unlabelled) "all steps" icon, at the top of a page, before reading the article at all - which defeats what was intended, of course. They clearly only wanted to show all steps to people who'd read the first one and wanted to see the rest, all on one page, but as you've pointed out, that doesn't work well, and they never seem to fix anything, no matter how obvious it is that it needs fixing.

    View Topic »
  • TooSlowTube. commented on mrstan's instructable Repair Dead COB LED Light Bulbs7 months ago
    Repair Dead COB LED Light Bulbs

    I've repaired one LED bulb by fitting a new electrolytic capacitor - the can shaped one.I think you're treating the symptom, not the cause, by just replacing the failed LED. The reason it failed was too much current. The reason for that was too little reactance, limiting the current. The reason it worked for a a while, then didn't, is probably because the reactance limiting the current went down.Most likely, the electrolytic capacitor overheated and lost some of it's electrolyte, making it into a smaller value capacitor. They all do that in the end, but it depends on the voltage, and the heat build up. Electrolytic capacitors have quite a short lifespan, compared to almost any other electronic component, in the best of conditions.If you're going to the trouble of repairing one, replace ...

    see more »

    I've repaired one LED bulb by fitting a new electrolytic capacitor - the can shaped one.I think you're treating the symptom, not the cause, by just replacing the failed LED. The reason it failed was too much current. The reason for that was too little reactance, limiting the current. The reason it worked for a a while, then didn't, is probably because the reactance limiting the current went down.Most likely, the electrolytic capacitor overheated and lost some of it's electrolyte, making it into a smaller value capacitor. They all do that in the end, but it depends on the voltage, and the heat build up. Electrolytic capacitors have quite a short lifespan, compared to almost any other electronic component, in the best of conditions.If you're going to the trouble of repairing one, replace that "can" capacitor, with a bigger value one, rated for a higher voltage. Otherwise, it won't be long at all before it needs repairing again.With a bigger value capacitor, the current will be less... you might need to replace the other one with a bigger value too. It will be dimmer, but will last longer as a result, and you should be fine just wiring across the dead LED.The candy shaped one is probably the current limiter. The value may be too small in the first place - they're trying to make the bulb brighter than it can handle. The electrolytic can shaped one is the voltage smoother / flicker reducer, but as that fails, there will be bigger voltage variations across it, which will overdrive the LEDS... I guess. I think the best solution is to replace and increase the value of both. They probably used a low voltage rating for the electrolytic capacitor, because it's cheaper. Putting in one with a higher voltage rating is probably the best way to make it last longer. A bigger value will also reduce flicker, making the light more comfortable to use. Increasing the value of the candy shaped one, should make the bulb dimmer, cooler and longer lasting.

    Better heatsinking would certainly help, but these things are clearly built to look bright at a price, not to last. As you say, the economics of fixing them properly are not good.I've been collecting the various different types I've bought that went wrong. The ones in a clear plastic shell died quickest, by far, so cutting that off would be a good start, to allow the heat to dissipate better.The other possibility is converting them to run off a DC supply. If you're fairly confident of the maximum voltage output of an old wall wart type AC->DC adapter, you can choose a limiting resistor to drive one or more of the panels wired in series.You just need a multimeter and some resistors you can substitute. Start with one you know is too high in value - e.g. most bright LEDs can take 20...

    see more »

    Better heatsinking would certainly help, but these things are clearly built to look bright at a price, not to last. As you say, the economics of fixing them properly are not good.I've been collecting the various different types I've bought that went wrong. The ones in a clear plastic shell died quickest, by far, so cutting that off would be a good start, to allow the heat to dissipate better.The other possibility is converting them to run off a DC supply. If you're fairly confident of the maximum voltage output of an old wall wart type AC->DC adapter, you can choose a limiting resistor to drive one or more of the panels wired in series.You just need a multimeter and some resistors you can substitute. Start with one you know is too high in value - e.g. most bright LEDs can take 20mA, so choose one that gives no more than 20mA if it's connected across the output of the DC supply (with the meter in series, measuring current), using R = V/I, where I is 20mA. A bigger value resistor gives less current. Then work your way down in value. You'll probably know when you hit a workable current, but 20-30mA is a likely limit.You'd need a fairly high wattage rated resistor, but it should last indefinitely. Use Power = I x I x R, or measure the voltage drop across it and use Power = V x V / R - to confirm you're within the rating.You can run multiple panels off one supply, if the wall wart can handle the current, of course - just use one resistor for each panel or series wired strings of LEDs.If there are a lot of LEDs on one panel, you may have to rewire it - cutting tracks to make smaller series groups of LEDs. Each one may drop as much as 2.5V under load, so you'd only drive three or four in series, off a 12V supply, but you could drive multiples of those groups, in parallel.The economics of doing that are better, if you already have the wall wart. Resistors are cheap, even fairly fat high power rated ones, and don't wear out unless you put too much current through them.

    View Instructable »
  • TooSlowTube. commented on loompiggytutorials's instructable Guide to Instructables7 months ago
    Guide to Instructables

    What's the intention of the flag icon, near top right on each article?On most sites, flagging means reporting a violation. Since that icon isn't explained or even labelled, I've avoided pressing it, in case that's what it does.I detest unlabelled icons. There ought to be a law... Someone should at least put some balloon text on it, that pops up when I hover the mouse over it - if that's meant to happen, it doesn't, at least not for me.

    View Instructable »
  • TooSlowTube. commented on randofo's instructable DIY Guitar Pedal9 months ago
    DIY Guitar Pedal

    I recently breadboarded a PNP silicon Fuzz Face (I'm waiting for some Germanium PNP to do it properly). It's basically the same circuit, but with opposite power rails, but I still used negative ground for the two jack sockets.You need to be able to bias it properly, to get a good sound. Replace the 10k fixed resistor from the collector of Q2 (the output transistor) to +9V, with a 470R to 1kR resistor, in series with a 5k to 22k pot (depending on the gain of your transistors).I deliberately looked through all my transistors for the lowest gain ones I had, measuring hfe (DC current gain), on a multimeter. You can make a simple test circuit to do it with any meter that can measure voltage or current. The original Fuzz Face used very low gain Germanium transistors. I found two PNP sili...

    see more »

    I recently breadboarded a PNP silicon Fuzz Face (I'm waiting for some Germanium PNP to do it properly). It's basically the same circuit, but with opposite power rails, but I still used negative ground for the two jack sockets.You need to be able to bias it properly, to get a good sound. Replace the 10k fixed resistor from the collector of Q2 (the output transistor) to +9V, with a 470R to 1kR resistor, in series with a 5k to 22k pot (depending on the gain of your transistors).I deliberately looked through all my transistors for the lowest gain ones I had, measuring hfe (DC current gain), on a multimeter. You can make a simple test circuit to do it with any meter that can measure voltage or current. The original Fuzz Face used very low gain Germanium transistors. I found two PNP silicon with a hfe of 130, which is low by modern standards.The 0.1uF input capacitor should be bigger, if you have low gain transistors - because the input impedance will be lower, which means the roll off frequency of the input decoupling will be higher. Think of the base of the transistor as a resistor to ground. For a low gain transistor, that's a small resistance. Lets call it R, and the input capacitor C. The roll off frequency is then1 / (2 x pi x R x C)below that frequency, the sound will be reduced (by 3dB per octave, I guess). So, you can see that if R is small, C needs to be big. On the original fuzz face, it was something like 2.2uF - a pretty big capacitor.Using higher gain transistors, as most of them are these days, you won't get the same sound as the original Fuzz Face, but you still will get fuzz. How much fuzz will depend on how you bias it. In my circuit, I used the normal 470R resistor in series with a 5k pot. I can adjust it from an almost clean amp sound (pot at zero Ohms), through various types of fuzz, to breaking up on everything but really loud notes, to no sound at all.Personally, I feel a bias pot that makes a useful extra control. At the very least, you should try a preset, and set it how you want it. Some people measure where they like it best then choose a fixed resistor.

    View Instructable »