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#21 |
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#22 |
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![]() Ok. So it seems most of the parts on the supicious rail were checkd, except PQ5 and PU701, right?
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#23 |
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#24 |
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![]() Unfortunately i can't find datasheet right no for PU701, but you can at least check whether 19V reach Pin1 and of course, you can check each pin for short to GND
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#25 |
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![]() How many amps is the board taking?
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#26 |
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![]() 5 6 7 14 15 & 32 are grounded
Pin #1 receives 19.5v |
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#27 |
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![]() How many amperes? Do you have a bench power supply? If yes, set it to 19.5V and power the board from it.
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#28 |
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#29 |
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![]() Check where the DC adaptor connects to the motherboard. Apply power from your power supply on the DC connector pins, just make sure which is +ve and -ve first.
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#30 |
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![]() PU701 Pin 6 & 15 short to GND means Main Power Rail short to GND. How could that Be missed before?
Last edited by Sephir0th; 10-19-2021 at 07:23 AM.. |
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#31 |
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#32 |
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![]() Do a visual check first to identify if something is physically damaged, otherwise Inject voltage on that line and see what gets hot. As always, start with 1V 1A then increase amp slowly if needed.
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#33 |
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![]() Did visual inspection before, totally clean mb.
Gonna inject voltage and report in 2 mins |
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#34 |
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![]() First, Share exact Résistance to GND there in Ohms Mode, Range 200 or Auto-Range to exclude a Short with a step down Circuit.
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#35 |
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![]() When i set it to Ω shows 20Ω not 0.
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#36 |
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![]() 20 Ohms are probably Bad News. Now you have to Check Resistance to GND of each coil. Look for a similar value...
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#37 |
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![]() I see same value only on PL400 (both pins) all other coils have values way beyond this.
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#38 |
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![]() That's fine then. So Voltage injection Like mentioned before. Pay Attention especially To PU401 and PU701.
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#39 |
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![]() I inject voltage on pin 6 (+) and GND (-), 1v 1a and drown only 0.4A, no shortcircuit indication.
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#40 |
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![]() They both share a common line through PR400. You could try removing PR400 to see which side is 20Ohms.
I suspect it might be a faulty PU701. These are fairly easy to remove and resolder. I'd try removing it and see if the 20Ohms is still there. Or you could just inject voltage, but with 20Ohms at 1V, I doubt anything will get hot (expected 0.05A flow). |
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