By: Tony
Nice video, sometimes the fun is just in hunting down the problem. Could the short be in one of the big white connectors for the memory expansion boards?
View ArticleBy: David
Did you consider trying the TTI current prober? I’ve had some luck with it for this kind of thing, especially when you can put 11 amps through the short, should a piece of piss to trace
View ArticleBy: Ray
Dave’s comment about a thermal imaging camera being useful caused me to make a mental connection. On the Hack A Day blog there was a post on Dec. 15th titled “A thermal imaging camera for your phone.”...
View ArticleBy: Alan
Could it be a faulty PSU ? Not giving enogh current, since nothing blew up, when you connected external PSU ?
View ArticleBy: Alex
Hello Dave, would also think it could be the power supply (given that the information of supplying 6 A is possibly not correct) it is not a real short given that quite some current can be normal on a...
View ArticleBy: Miad
Try giving the 11 amps with the memory cards and the processor board mounted. Also is it possible that the 3.3v plane is shorted somewhere in the board? Maybe it could be visible by placing the board...
View ArticleBy: Alan
also, rememember that the initial 11,4 A never increased, but decreased to 10,something in a while ?
View ArticleBy: Rachie
There appears to be a cracked relay case at 29:19. It seems unlikely a relay could short out like this, but it looks quite suspicious.
View ArticleBy: Alexandre Jasmin
Would it make sense to power the thing up by supplying the 3.3v rail from your high current source and try to guess what component failed by using the scope?
View ArticleBy: EEVblog
There ma be something wrong with the supply, and it needs checking. But if so, that’s a different issue. A normal 3.3V system rail should not measure 0.1ohms both ways on a multimeter. I smell a rat.
View ArticleBy: Phil Hobbs
3.3V/11A is 0.3 ohms, so if that’s accurate, the leads are also about 0.15 ohms, which seems a bit high. However, if you leave the bench supply connected you can trace tens millivolts instead of...
View ArticleBy: Alex
Hello Dave, yes thinking twice it is still a bit high current for working condition (so yes could be that only your lab supply was able to maintain driving current thru the working chips and the...
View ArticleBy: huh
I see some power 3 terminal devices on that board. Could one of them be a power mosfet? They’re known for often becoming a short when they fail.
View ArticleBy: swedeham
Hi Dave Why not try using a tone signal like a 1Khz signal connected at the 3.3 volt socket and then you trace it with a low power amp ie a pair of active PC speakers and use the 3.5mm plug as a...
View ArticleBy: f4eru
Easier : put the 10 amp Probe around the voltage with the multimeter exactly like you did with resistance => you should find quicker wich cap has the lowest voltage
View ArticleBy: Worf
I think Dave jinxed it at the beginning when he said it was a live debugging and if you’ve come to the end and it’s still not fixed…
View ArticleBy: Zeke
I’ve had a rash of such shorted FET’s lately. Of course the equipment is 15 years old, and the motors they are driving are freezing up due to lack of lubrication. Lube the motors and add fuse...
View ArticleBy: Joe
Another video Dave!! You can fix it!!! Then sell raffle tickets or auction it off..
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By: Sam Reaves
Dave, Glad to see that you are getting back to it. I would think about pulling one of the chips on the +3.3V supply. Also you have the TTI Iprobe. You should be able to trace the current and see where...
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By: swedeham
Yes f4eru I agree ,i guess i just answered what i know would have worked and he does have scopes in spades ,but he seem to use moltimeters in a big way. Let’s see what he comes up with
View ArticleBy: Ice Skate
Hi Dave, very very good video, showing pratical EE’s skills is awesome. I am awaiting the second part with some genius methods proposed in the forum’s thread to track down this short! Keep it on going...
View ArticleBy: KingS Twisted
Dave… Don’t you wish you had some cool device that could trace 11 amps of current through a circuit board. Something like a “AIM-TTi I-Prober 520 Current Probe” (EEVblog #296).
View ArticleBy: Kasper
Maybe you could spray some cold spray on the board while powering it? That should reveal any hotspots like shorted caps.
View ArticleBy: Nicholas Vinen
Or perhaps isopropyl alcohol, it should evaporate much faster when it hits something hot.
View ArticleBy: Alan
OK, I’m not really into this, but : given the fact that an ext. PSU haven’t blown anything, and given the fact that the actual current (pushed by the ext. PSU)only dropped with the time powered, I...
View ArticleBy: schen
Worst case, nastiest buggiest problem that could have happened is maybe the oscillator or some other common signal going to the four digital ICs has gone bad. Could also be a huge red herring. There...
View ArticleBy: f4eru
Good idea. The circuits may draw too much current due to non functionnal parts of the circuitry. Test to do : power the 3.3 V externally, the rest on the original supply…
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By: Francisco
Yes, there is something not right with the relay component, look around minute 12:48… I would first check that out! Thanks
View ArticleBy: xDR1TeK
Won’t powering up the 3.3v circuit, while a component is unloading its net or nodes, blow up something else?
View ArticleBy: xDR1TeK
I mean if the component were to be removed and hence unloading its nets or nodes.
View ArticleBy: Chuck
Dave Noticed you had your hands on the PCB while flexing at time 18:30ish and the edge cap read .100 ohm, this may have been you body impedance pressing on the board when you where flexing it..
View ArticleBy: Jeffrey Burgher
Today, I went to the beach with my children. I found a sea shell and gave it tomy 4 year old daughter and said “You can hear the ocean if you put this to your ear.” Sheplaced the shell to her ear and...
View ArticleBy: Mario Beul
9 Mistakes In Marco Bitran That Make You Look Dumb If you are going to exist you will probably be looking for things to do in Boston. There are lots of things that you simply should not miss while you...
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