MV1C not saving settings

[obitus1990]

Hi, I replaced the original battery with a CR2032 and did the modification to remove the charging circuitry. Prior to doing this, the system would not save settings, as the original battery was dead. It still will not save the game soft dips after modification, but, it is indeed saving the clock settings.

A couple of years back, I modified the board to accept a UniBios, using, I believe, a NeoBiosMasta reverse PLCC socket board. If I change the settings there, say, to a different region, those settings don't save, either. It always boots to Europe as the region after a power cycle.

Otherwise, it works great. Any idea why soft dips don't save, but, clock settings do?

Thanks!

 

[mgolisch]

Hi,
the mostlikely explanation is that the backup ram ICs doesnt get power from the battery at all or the battery voltage is below the required 2v to retain the data.Hence settings are lost when the board is turned off.
The date and time are saved in the rtc and retained by that. It has nothing to do with the backup ram other than beeing powered by the same battery.
So i think easiest way to verify is to measure voltage on the vcc pin (pin 28 - first, leftmost pin on top side) of both backup ram ICs while the board is not powered.

 

[Neo-Alec]

Did you clear the backup ram after installing the new battery?

 

[obitus1990]

Did you clear the backup ram after installing the new battery?

Yes.

 

[obitus1990]

Hi,
the mostlikely explanation is that the backup ram ICs doesnt get power from the battery at all or the battery voltage is below the required 2v to retain the data.Hence settings are lost when the board is turned off.
The date and time are saved in the rtc and retained by that. It has nothing to do with the backup ram other than beeing powered by the same battery.
So i think easiest way to verify is to measure voltage on the vcc pin (pin 28 - first, leftmost pin on top side) of both backup ram ICs while the board is not powered.

I am assuming the backup RAMs are the two Winbond chips in the backup section, so, I metered both at pin 28 and found that there was 2.8 volts there when powered off. Do these ICs often fail?

 

[Raph_friend]

I am assuming the backup RAMs are the two Winbond chips in the backup section, so, I metered both at pin 28 and found that there was 2.8 volts there when powered off. Do these ICs often fail?

If RAMs are bad you will get a RAM error screen.