While browsing through your comments I checked a link to the video about the little pink 3A power supply and was met with silence from my speakers. It turned out that their plug-in power supply had died.
I popped it open expecting to see the remnants of a sooty bang inside, but the primary seemed intact. It turned out a component on the secondary had failed, and ironically I was able to scavenge the component I needed from the little pink power supply.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
I popped it open expecting to see the remnants of a sooty bang inside, but the primary seemed intact. It turned out a component on the secondary had failed, and ironically I was able to scavenge the component I needed from the little pink power supply.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
Hi bigclive. I love your videos and the learning I get from them. At the same time I'm fascinated by your right hand which over the years of your videos often seems to show some recent damage 😉 Are you a boxer, or is this an occupational hazard, or just the odd bad client? I'm kind of prone to wearing the odd scar myself and I'd love to know how you get yours. 🙂
Time to crack out the epoxy! 😛
Clive Poundland are doing 5v 1amp usb charger plugs!
That diode probably runs too hot, seen it in some other PSUs.
What kind of speakers do you use on your laptop? I don't use any external ones on my laptop, but I have a set of Sound Sticks on my iMac.
Awesome ! Good to know what fails on these
Thanks – an inspiring video. I've just taken apart a failed PSU that's been sitting on my desk for about a year, and found that it's also failed in the same way. New diode ordered form e-bay, should hopefully get it working again, and saved it from landfill!
I got a speaker amplifier thing here (from a set with small speakers), the power supply got lost at some point and I had to resort using 6x AA batteries instead. I let them in after usage, and some times they were either all completely flat, or just 2-3 of them. I had no clue why it happened, ordered external 6x AA holders with the correct plug and used it like that. Worked nicely, but not for too long until the same thing happened again.
Then I got myself together and ordered cheap USB 5V to 9V Step Up converters from china. They worked with the Power Bank! BUT the next day the power bank did it's short circuit shut-off, every time I plugged it in (without even turning on the amp). First I thought it was the Step Up thing, but both had the same reaction. So (before trying any other USB ports on anything else…) I opened the thing up and looked into it. Nothing wrong at all.
Got the power meter out: continuity between all + and – of all inputs.
I was shocked, losing my 12 year old little 5W ampflifier. But the more I tested the continuity, suddenly there was none anymore. Instead of beeping it showed raising numbers. I plugged it in, no short circuit anymore :0
Then, 10 minutes later, it was again shorted. This time I took the charger doctor and plugged it to a 1A power supply without short circuit protection. It feeps a bit when I plug it in, the voltage shows 3V for less than half a second and then everything is back to normal.
May it also be a (smaller) diode, that failed in there? It doesn't really matter, because it works as long as I don't use the power bank, but it confused me and I wondered which component would cause such a thing. Is it a resistor between + and – ? Or more likely a diode? If I ever find out what caused it, the AA batteries, which died a horrible and unnecessary death, will have their vengeance! Or something.
(The amp has 9V 600mA max. input)
Those diodes are very common. "xxx560" is a dead giveaway that it is rated IF=5A and VR=60V. The usual name for it is "SB560" and they are around since at least 1995. Back then they did not have the 60V reverse voltage and the main 5A Schottky diode was the "SB540" 5A /40V
It's always fun when you buy what amounts to garbage and it turns out to have a use that it was never intended for. For instance I bought what would be considered a cheap poundland 3 LED flashlight and mounted a laser element in it. See I got tired of holding the button whilst playing with the cat. It also wore out the button in it's original casing. I had originally bought the flashlights to put colored LEDs in instead of the standard cold white ones. I did that with most of them and it turned out pretty well resulting in what I call "Chromatic" flashlights. Long story short I reamed out the reflector to fit the laser module and it worked pretty well. It's my favorite kind of hacking…
"To contain the bang" haha were cut from the same cloth! Full confidence in our abilities
Stupid glue works great at resealing those cases. And gluing your fingers together.
i mean, youve got it open, wouldnt you wanna double check some other basic components, like the caps, just to see if theyre getting on there in years? a minute now might save you hours later if it fails again
Consider that the speakers this powered would probably have tolerated a 12V supply. You can pop them open to see if there's an abnormally low voltage threshold like 10V but it's doubtful for an audio amp IC or typical film and electrolytic capacitors… and with a fixed gain stage, you're not increasing the stress on it much. In fact the higher voltage 12V PSU might have even allowed slightly higher volume before distortion set in.
Regarding the auto vs. manual range on the DMM. I use a Fluke 87 and 789, both of which default to auto-range. This seems to be fine for ohms, but if I am checking voltage, the first thing I do is manually change the range to one step higher than what I expect. I do a lot of work on industrial equipment, and you would be amazed the number of times I have seen folks fooled when troubleshooting a piece of equipment by not noticing the 'm' before the V in auto-range mode, and reading something like 117.4 mV and believe there is 120 Volts present on a control circuit, when it is dead, and they are just reading 'floating' voltages being picked up by adjacent powered wires. Switching to 400 V range totally eliminates wasted time.
Ah, Clive… Gaffer's tape fixes everything. 🙂
Gaffer's Tape is like the Force from Star Wars, it has a light side and a dark side and it holds the Universe together.