Member Avatar for rasheed_90009

HI guys ...my pc spec is as follows
AMD Athlon 64 processor
3000+
1.81GHz
ASUS A8NV
My probelm started when i started the computer...
it shows a warning CMOS checksum bad error;CMOS time/date not set
i got information that its the problem of CMOS battery...i replaced the battery..
even then i got the error... please help me...

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  • Latest Post Latest Post by 85mechanic

Dani AI

Generated

As @rasheed90009 reported, the board still shows "CMOS checksum bad / CMOS time/date not set" after a battery change. Earlier replies from @Rik, , and pointed toward BIOS and reset options; the advice below expands with hardware-level diagnostics and practical tests that often identify why a replaced battery does not stop the checksum error.

A CMOS checksum error means the BIOS found the stored configuration corrupted or unreadable at POST. Common root causes beyond a weak coin cell include poor battery contact or holder corrosion, lack of standby power to the RTC, failed motherboard components that feed the CMOS/RTC, or BIOS/firmware damage. Malware is an uncommon cause; hardware faults are the likelier explanation when the clock keeps resetting.

Helpful diagnostic checklist (safe, order-of-operations style):

  • Confirm the coin cell type and voltage off-board (typical is CR2032 ≈ 3.0V). A meter reading well under 3V indicates a bad cell even if new.
  • Inspect and clean the battery holder/contacts for corrosion, bent springs, or insulating residue; re-seat the cell firmly.
  • Visually check the motherboard for bulging/leaking capacitors, burn marks or corrosion around the RTC/coin-cell area.
  • Verify the PSU standby rail that powers the RTC (5VSB) is present using a multimeter on the main ATX connector — leave live-voltage checks to those comfortable with mains-safe measurement.
  • Try a known-good battery and, if available, a different PSU to rule out holder or PSU failure.
  • If hardware checks pass, use the board’s official BIOS recovery/flashing method with an official ASUS image; follow ASUS documentation exactly.

If these steps still leave the checksum error, the RTC/CMOS circuit or the BIOS chip itself is likely failing and board repair or replacement is usually required. Safety note: power should be removed before handling components; live-voltage measurements carry risk and can be left to a technician.

Recommended Answers

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Member Avatar for Rik_

Have you set your bios correctly after replacing the battery?
Please refer to your motherboard manual.

Member Avatar for rasheed_90009

Have you set your bios correctly after replacing the battery?
Please refer to your motherboard manual.

i dont know how to correct the bios settings...can u explain that...

Member Avatar for Rik_

As I said, check your motherboad manual for more information.

Member Avatar for rasheed_90009

As I said, check your motherboad manual for more information.

r u talking about correcting the system time and date in the bios setup?..

Member Avatar for rasheed_90009

You need to read the manual. There are lots of different bioses out there. The manual should tell you what you need to do.

under which subject it comes?

Member Avatar for designbooks

a couple of problems could be causing this, either a virus changing your cmos settings or you modified the settings. you should run a virus scan and if that doesent fix the problem note the current settings and reset values to default.

Member Avatar for Rik_

You need to read through the whole lot.

Member Avatar for caperjack

You need to read through the whole lot.

lol.
did you go into the bios and set defaults and save settings after you install the new battery

Member Avatar for 85mechanic

try resetting the bios settings, the best way is using a reset jumper on your board(read the manual on where it is). then edit the settings when you restart. most machines bios are accessed by pressing delete at start up.

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