Re: Acer Aspire 5740g dead (no power - no lights)
I've changed only the KBC BIOS on U16 and the laptop started working again!
The situation was this:
- No S5_ENABLE on TPS51223 (pin 18 TPS51223)
- 3.3V and 5V OK from TPS51223 (C716, C732)
- No SPI communication with U16 (pin 1 U16)
Hope it helps someone with the same problem!...
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Re: Acer Aspire 5740g dead (no power - no lights)
Hi,
thanks for your explanation!
I've checked the CS pin (pin 1 according to MX25L1005 datasheet) on U16 and it is fixed on 3.3V (not changing) so I assume there's no communication with EC-BIOS on U16 (re-checked also 5V on C716 and 3.3V on C732 and they are at the correct voltage).
I also checked pin 1 on U56, but no communication detected. I cannot identify the model of the BIOS chip on U56 because the printings are blurred ('cause of the sticker).
Do you think I can assume...
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Re: Acer Aspire 5740g dead (no power - no lights)
Ok.. sorry for the question but what is EC BIOS?
Tomorrow I'll check the signals on U16 with an oscilloscope to see if communication with BIOS chip (that, at the end, is an SPI flash) is present, if there's no data communication should I suppose it is a problem with the BIOS chip on U16?
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Re: Acer Aspire 5740g dead (no power - no lights)
Hi,
I have an Aspire 5740g dead too.
Following this discussion I checked the 3.3V and the 5V outputs of the TPS51223 on C732 e C716 (that are connected to VREG3 and VREG5 of TPS51123) and there are 3.3V and 5V. Anyway no power lights, no battery charge... what else should be checked? Could it be the BIOS problem even if the voltage is present?
Thanks.
Samuele.
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