Toshiba l735 wont hold time/date.

[scobie_21]

Hi I have a L735 that wont hold the date/time if the ac adapter and or main battery is removed. Initially the CMOS battery was flat so I replaced it and after a short time that went flat aswell (could be bad battery). I replaced it with new CR2032 and the voltage after 3 days is still 2.95/3v ok but still wont hold date/time after power is removed.

The schematic I need is DABU5MB18A0 (BU5M) I have the BU5D Im not sure if there any major difference but the PCH is numbered different.
The laptop works perfectly other than this issue.

If anybody has the schematic for this I would be grateful, I was thinking of reflowing the PCh but I would like to do some measurements first as there is sign of slight spillage around the CMOS battery holder which I removed and resoldered.
Thanks in advance

[dj_ricoh]

Re: Toshiba l735 wont hold time/date.

if the battery its rated 3v then it needs 3.3v to charge no?
if you got a notebook battery rated with 11.4 or 11.8 the charging voltage will pass that voltage.
like on a car the battery its rated 12v but when you put the DMM when the car its running you will see 13.3-14(depend)

[sorinac]

Re: Toshiba l735 wont hold time/date.

if you have the bu5d schematic use that , the rtc circuit is the same only notations are different .
check D8 diode from bu5d schematic

if the battery its rated 3v then it needs 3.3v to charge no?
if you got a notebook battery rated with 11.4 or 11.8 the charging voltage will pass that voltage.
like on a car the battery its rated 12v but when you put the DMM when the car its running you will see 13.3-14(depend)

the cmos battery is not rechargeable

[spleenharvester]

Re: Toshiba l735 wont hold time/date.

I would try and flash the BIOS if possible (presuming the lack of CMOS battery function is not dangerous?)

[scobie_21]

Re: Toshiba l735 wont hold time/date.

I would try and flash the BIOS if possible (presuming the lack of CMOS battery function is not dangerous?)

I am goig to try that next but I dont think the bios is the issue as the RTc circuit is handled by the Pch.

[scobie_21]

Re: Toshiba l735 wont hold time/date.

if you have the bu5d schematic use that , the rtc circuit is the same only notations are different .
check D8 diode from bu5d schematic




the cmos battery is not rechargeable

Yeah I ws just hoping to get the correct one as there are a few components name differently, but you are right failing that I will check out those diodes.

Thanks for the input folks.