Re: many bios corrupted !!!
I also have the same question but as an electronic engineer I would say that the lack of differential mechanism, lack of error detection and correction mechanisms and higher bit rates can result to BIOS corruption but thats only theory (more precisely my theory). If anyone else has another opinion would be nice to share it here.
tzoupkas
Member
Last Activity: 05-27-2023, 12:31 PM
Joined: 06-29-2014
Location: Ptolemaida
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Re: compaq cq20 no power
yes order the kbc and place it.Leave a comment:
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Re: compaq cq20 no power
Even if it so (shorted caps) KBC is already dead. Change KBC, measure voltages, then check caps. My opinion I have done this many times never had issue with caps near KBC.Leave a comment:
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Re: compaq cq20 no power
No standby current, just voltages near KBC must be 3Volts. As for the other compaq you said make a new post and me and the other guys will help you. If you have the compaq in front I can help you now but in a new post. Thank you.Leave a comment:
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Re: compaq cq20 no power
When you will remove the KBC plug power, measure again the voltages if voltages are not normal then check for short in caps but you will not need it. Hope I helped you.Leave a comment:
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Re: compaq cq20 no power
yes changed it without second thought, as I said 90% KBC is off in such cases, changed it and board will come in life straight away.Leave a comment:
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Re: compaq cq20 no power
Check voltages at KBC U18 in your case. Especially the +3VAL and +3VAL_KBC see if they are 3V and check with your finger if it is getting unusually hot.Leave a comment:
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Re: compaq cq20 no power
Stable 19.16 Volts?Leave a comment:
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Re: compaq cq20 no power
I see. When you plug your power adapter measure the voltage at coil L1 it must be near DC jack. Don't press power button just see the measurement and see if it ripples lets say between 18,4V and 19,5 volts. Do that for start and we will see later.Leave a comment:
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Re: compaq cq20 no power
Wait! first things first, stay calm. What did you changed on the mobo?Leave a comment:
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Re: compaq cq20 no power
Please check for short in +3VS rail, but in my opinion check for short on any rail related with U18. U18 might be 90% off, when U1 is false.Leave a comment:
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Re: compaq cq20 no power
also U18 might me burned, when you will change the U1 touch with your finger the U18 for overheating.Leave a comment:
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Re: compaq cq20 no power
hello my friend I would change the U1 LM393 for start as I don't get the correct voltage at gate pin. Do that if possible and we will see what to do next.Leave a comment:
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Re: Presario CQ62 Dead Board Help
Exactly as ktmmotocross said previously 5V and 3V are always on try to measure them first next all the others. A quick way to do it is by measuring the pins voltage at the battery adapter if no one in giving 3.3 V than the problem is somewhere else.Leave a comment:
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