Acer Z1-601 all in one schematic (short on VCC)

[Dannyx]

Good day folks. Someone came in with this picture frame today and it's shutting down the power brick...short on VCC obviously. What is NOT so obvious unfortunately is where the short is located. I took the little board off the chassis and soldered a wire to VCC (in place of a jumper resistor) which I connected to my supply and gently increased the current to about 2a....nothing's even warm. I let it cook like that for 5 minutes hoping some part of the board would get hotter than the rest, but I couldn't find it, at least not by the traditional method of palming the board and using iso alcohol. A thermal camera would be better suited for this, but forget about it: too expensive for too little use...any chance we can find a schematic ?

I posted some pics....I hoped it'd be a shorted FET or cap somewhere, but no: nothing, no heat at all, yet it's still eating 2a....really wish I could crank it more, but 2a is the maximum my bench supply at work can muster. I have a DPS ebay one at home which can pump harder than that, but I was thinking of something a little more extreme: UPS battery ? I WANT FLAMES ! It's 12v while the adapter is 19v, so it's not exceeding the rail, but it should still cause smoke to come out of something - provided the battery/wires don't give in....

[piernov]

Re: Acer Z1-601 all in one schematic (short on VCC)

What is the exact resistance to ground?

[Dannyx]

Re: Acer Z1-601 all in one schematic (short on VCC)

Absolute zero - dead short. No shorts on other buck converters though - just on the "primary" so to say. No, the power jack is fine and it's also before that resistor I removed to add my wire, so what I send into the board with my PSU is not reaching the jack anyway.

[SMDFlea]

Re: Acer Z1-601 all in one schematic (short on VCC)

I found a schematic,not sure if its the right one but it may help .

[Dannyx]

Re: Acer Z1-601 all in one schematic (short on VCC)

Thanks. It appears to be similar, though I'm not sure if it's just a coincidence or it's the same board indeed. Still, no sign of that short....it happens on page 30 on the right. That's where I get my short. Before that resistor, there is no short....I believe I tested just about every transistor on there...even if it were a shorted trace it should at least get warm.....

[SMDFlea]

Re: Acer Z1-601 all in one schematic (short on VCC)

No,its not the right schematic, but similar. Theres a boardview, i can`t find it for free though, only on paid sites .

Lengda UM1B_MAIN_PCB V1.01 boardview.rar

https://e***************************5-aio

http://vl****************************57

[Dannyx]

Re: Acer Z1-601 all in one schematic (short on VCC)

I took the board home with me and hooked it up to my own PSU which can do 10+ amps and I did just that: cranked up the SOB until something DID get hot: a couple of caps near the top-right corner of the heatsink of the CPU (as seen in the first pic). I'll try pulling those off tomorrow to see if the short's still there...don't know why it took 5.5A before they finally started sizzling, but still...I got it hopefully

[Dannyx]

Re: Acer Z1-601 all in one schematic (short on VCC)

Almost forgot to update you guys on how it all went: PC is up and running again The small cap which sizzled was indeed shorted. Removed it and it's now good as new. No trippy side-effects either. So that PSU really paid for itself by helping me identify that short So the next time you get a short and can't seem to figure out where it's coming from, just pump lots of current through it and it's guaranteed to show up (as long as you don't exceed the rail's nominal voltage, of course). I was "lucky" to have a short on the 19v rail, so I could crank as high as I needed to without exceeding the rail and damaging something. Cheers guys !

[totto210]

Re: Acer Z1-601 all in one schematic (short on VCC)

I found a schematic,not sure if its the right one but it may help .

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