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MVS Mv-1c Draining Batteries

Lastsix

Lastsix

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I have an mv1c that used to drain a full battery In about 30 minutes. I installed a ml2032 and universe bios to no effect. Removing capacitors c3, pc2 and pc4 from the board slowed the drain to about 24 hours.

This is not a major issue and I understand that this can happen to the mv1b and mv1c sometimes; but does anyone have any experience solving this issue?
 
If everything is fine, how long should a new battery or a fully charged battery last? I have 3 mv1cs, and the new battery runs out in about a day on all of them.
 
MaRC said:
If everything is fine, how long should a new battery or a fully charged battery last? I have 3 mv1cs, and the new battery runs out in about a day on all of them.
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All three of my CR2032's on my MV1C and other two MVS boards have literally lasted for years so far.

I'm pretty sure the one in the MV1C was installed in 2016, and I don't think I've ever replaced it yet.
 
Don't know if it makes a difference, but my charging circuit is still intact.

Can different brands of sram drain faster? I can pull some off another board but it's the same brand/type.
 
What brand is the RAM? Post here by James of JNX says the Sony RAM is usually good.

https://www.neo-geo.com/forums/index.php?threads/mv1-a-mv1-fz-battery-mod.250241/#post-3997892

As for how long it lasts, I'm just about to wrap up a test on my MV-1A where it looks like it will have taken 12 days after coming off power to drop from 2.90V to 2.00V and the last couple days of that test it was dropping only 0.01V/day.

Prior to removing C3, it would completely drain the battery in 24 hours dropping 0.01V every few seconds after coming off power.

I am using an ML2032 with the recharging circuit still intact as well.

I plan to put it back on power tomorrow and make sure it is still holding calendar/clock and all the other settings at 2.00V then run another test to see how long it takes to get down to 1.50V and see if it still holds the backup RAM settings at that voltage. I would expect it to be at least a couple months.
 
I'd personally disable the charging circuit and use a standard CR2032.
 
I followed the instructions online to mod and disable the charging circuit for my MV1C, MV1FS and MV4F, and they're all working great with a CR2032. No need for recharging.
 
Last edited:
thegreathopper said:
How long does a CR2032 hold a charge, I may do this to a couple if one slots I have.
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Probably 8-10 years!

When I used rechargeable batteries in my 4-slots, they'd drain so quickly. Recently removed the resistor on 2 of those and went with the CR2032.

It's all reversable if you want the rechargeable battery back, but you probably won't go back. I got sick of setting the motherboard up on each power cycle.
 
I disabled the charging circuit on my mv1c and the battery was still dead in less than a day. With the battery removed and the power on I still see 3.7 volts being pushed to the battery holder.
 
Is that with a ML2032 or a CR2032?
Lastsix said:
I disabled the charging circuit on my mv1c and the battery was still dead in less than a day. With the battery removed and the power on I still see 3.7 volts being pushed to the battery holder.
Click to expand...
 
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