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MV1B - Settings not saved [solved]

L

LaGriff

Beginner
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Sep 10, 2021
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France
Hello everyone,

Question level beginner.

I got a mv1b and I installed a battery holder on it, but saves are not working. I just took off the old battery and installed the holder, I didn't not remove anything I would like to use it with ml2032 not cr2032.

I tested the electric tension on the battery holder it is around 3.4, so current is getting there.

I switched the ml 2032 with another slot which is perfectly working (same holder), and it is ok so it is not the battery itself.

What could I test ?

Thanks for your help !
 
How are you testing saving? Do the operator settings have logs stored of the games played? Did you allow a full game over to save in-game scores and settings?
 
simple test,
with the battery fitted and the board not plugged into a harness,
check for voltage on the pins of the sram
 
I wasn't sure if ML2032 cells were safe to use in an MVS as they have a lower charging voltage than the original. LIR2032 cells seemed to be a better match.
 
Hi everyone,

@Neo-Alec So I am testing it by setting up the calendar, then setting up the game options (showing the difficulty level on screen for exemple), then I play a bit and leave the board on for a few hours, then I turn it off and turn it on again, and well nothing is saved, no calendar, no book keeping, nothing.

@bodgit I should check that, I am reading eveything everywhere, some people tell you can use one or the other, some people say ml other lir, honestly I feel so confused...

@stj how can I do that please ? I feel like there are 4 chips un the backup area, I suppose those would be ram 3 and 4, what pins on sram chip should I check ? Sorry, real beginner here... About the cells, do you feel like ML are not good too ?

Thanks for your help !
 
pin to check on the ram is 28 the last pin - top-right.
and ground shouldnt be hard to find. ;)

as for ML - last time i looked at those and the other similar ones, the capacity seemed a bit shit for their size.
a cr2032 costs peanuts now - i can get a 10pack for a €.
so using a rechargeable seems pointless - specially as you would need to keep it charged by running the board for hours
 
@stj Thanks, this lead me on the good way !

Actually, I realised that I always tested the voltage on the battery, and the continuity of my solders on the holder and the mvs board, but I had never checked the voltage on the holder itself once the battery was inserted.
And bingo, even if the continuity of the circuits was ok on the holder, the voltage was at zero... 8| So after watching very carefully, I noticed the battery was not touching the - connector when fully inserted... So I added a very little point of solder on the - connector, reinserted the battery and voilà ;) There we were, voltage was fine on the holder.
Resoldered everything, checked the sram (hurray I found the ground :D) and I had current everywhere, and my settings are now keeping in memory.

I will really have to think about this cr2032 thing ! But I kinda like the idea to keep it working as before...

Thanks sincerely to all of you !
 
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i have not seen a bad contact on a 2032 holder,
what type is it?
i use the ones from pc motherboards - much better than the ones with a contact on the top. :)
 
Actually, I think it is a good one, cause when I tested the voltage on the holder with a cr2032 it was perfect, it was only faulty with my two ml2032. And after checking my 2 ml2032 I noticed they were a very little bit curved in the middle wich was causing the lack of contact. And that is when I thought I had to add a very tiny bit of solder so it would make contact in the middle too as it was working on the borders of the batteries when I was not inserting them totally.

I am using this holder, I really like it, it is perfectly made for the mv1b and you can install it horizontally or vertically.
support-batterie.PNG
support-batterie-2.PNG
 
i could have told you that holder wouldnt work,
the green laq on the pcb is obviously higher than the tinned copper pad :D
maybe only by a very tiny amount, but still enough to keep the battery off the pad.
 
I got exactly the same model installed on another board, and it worked without any modification, probably coming from another batch :) If I ever need to install another, now I know what to check before installing it !
 
I made something very similar and I make a point of always tinning that centre pad so it's slightly raised. I have a sacrificial 2032 cell that I insert into every assembled holder and check that I can measure the voltage before shipping them.
 
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