Did I total this NES game?

[2600Ibarelyknewher]

In need of some assistance, I put a battery holder into my copy of Crystalis for NES. I may have reversed the battery by accident when I originally installed it. Now the game no longer saves for more than 10 minutes. I’ve had issues with other NES games and received great advice from you folks. Any assistance would be much appreciated. I’ve checked continuity from almost every point that the battery leads connect to and no success so far. I have attempted a couple small jumper wires to no avail as noted in my picture below. 

Edited September 13, 2020 by 2600Ibarelyknewher

[Keatah]

Ohh heavens absolutely not. A little cleanup and it would be like new again.

 

[2600Ibarelyknewher]

2 minutes ago, Keatah said:

Ohh heavens absolutely not. A little cleanup and it would be like new again.

 

I’m just not sure where to start? Any advice I know you can’t look at it yourself. Nothing looks damaged, where should I start? I thought it was the reverse of the battery that did it. 

[+wongojack]

Did you try a different battery?

[2600Ibarelyknewher]

4 minutes ago, wongojack said:

Did you try a different battery?

Yes I did, I’ve tried two other “yellow” edged batteries from eBay. I made the mistake of positive into the negative terminal because the pins are the same sizes on the batteries. This would be my third different battery. 

[+-^CrossBow^-]

Where did you get that battery holder? I've been looking for some low profile ones that doesn't require the cartridge to be modified internally etc but those that use these seem to keep that to themselves?

 

[2600Ibarelyknewher]

14 minutes ago, -^CrossBow^- said:

Where did you get that battery holder? I've been looking for some low profile ones that doesn't require the cartridge to be modified internally etc but those that use these seem to keep that to themselves?

 

https://www.ebay.ca/itm/10PCS-Plastic-Housing-CR2032-Button-Cell-Battery-Socket-Holder-CasNWUS/324003268883?pageci=a0f3bf98-ad18-4a60-b056-3fa1c7ca5808, here’s the link, they are not particularly well made but they don’t require much modification to use, only the negative terminal needs to be made small on the holder. Use super glue to hold the metal piece in, you can dab glue in on the other side where the two metal pegs go into the holder. 

Edited September 13, 2020 by 2600Ibarelyknewher

[2600Ibarelyknewher]

I feel like i may have fried something on the board when I switch the battery terminals. I just have no idea where to look for such an issue or how. 

[+-^CrossBow^-]

2 minutes ago, 2600Ibarelyknewher said:

https://www.ebay.ca/itm/10PCS-Plastic-Housing-CR2032-Button-Cell-Battery-Socket-Holder-CasNWUS/324003268883?pageci=a0f3bf98-ad18-4a60-b056-3fa1c7ca5808, here’s the link, they are not particularly well made but they don’t require much modification to use, only the negative terminal needs to be made small on the holder. Use super glue to hold the metal piece in, you can dab glue in on the other side where the two metal pegs go into the holder. 

Looks like if you have a battery in it, then it should be strong enough to just bend the tabs where you need them to be. I know I've heard of others using similar SMD battery holders, but that the tabs on them were still at the right length to just bend them straight down and still solder them into the old battery via openings? I have some that are pretty darn low profile and they work well enough. But I still have to cut away some of the material on them in order to get them to an even lower profile overall.

 

[2600Ibarelyknewher]

4 minutes ago, -^CrossBow^- said:

Looks like if you have a battery in it, then it should be strong enough to just bend the tabs where you need them to be. I know I've heard of others using similar SMD battery holders, but that the tabs on them were still at the right length to just bend them straight down and still solder them into the old battery via openings? I have some that are pretty darn low profile and they work well enough. But I still have to cut away some of the material on them in order to get them to an even lower profile overall.

 

No modification  is required with these holders to the plastic at all. Very low profile. 

[+wongojack]

I think there should be diodes protecting the actual chips from reverse polarity, and 3v is so low that I wouldn't think you'd do damage (to a diode or a chip).  I guess its possible.

 

What happens if you have no battery in there at all?

[2600Ibarelyknewher]

7 minutes ago, wongojack said:

I think there should be diodes protecting the actual chips from reverse polarity, and 3v is so low that I wouldn't think you'd do damage (to a diode or a chip).  I guess its possible.

 

What happens if you have no battery in there at all?

I’ll try it when I get home. Appreciate the advice as always. What should happen if everything was okay when I remove it? I’d be willing to replace the diodes on this I also have a tester for those. Just not sure what they should be showing if they were okay. Do you think the caps could be damaged as well? There’s a couple at the top.

[+wongojack]

I dunno, what usually happens with these NES games when there is no battery?  I've never tried that.  I guess what I am thinking is that if you try to save without a battery and get the same behavior (doesn't hold save after 10 mins).  Then you could sorta start over.  Check everything you've done and try to see if something isn't quite hooked up right.

[2600Ibarelyknewher]

11 hours ago, wongojack said:

I dunno, what usually happens with these NES games when there is no battery?  I've never tried that.  I guess what I am thinking is that if you try to save without a battery and get the same behavior (doesn't hold save after 10 mins).  Then you could sorta start over.  Check everything you've done and try to see if something isn't quite hooked up right.

It seems to loose the save faster... I wonder if I should just replace the components around the battery like these resistors and caps etc. 

[emerson]

If you remove the battery and save to ram, the save file should be present as long as the nes provides power to the cartridge. The file will erase once you turn the nes off. Hitting the reset button should not erase the ram.

 

If you want to test if the ram chip is okay, I suggest removing the battery and creating a save file, let the nes sit on for 10-15 minutes since you say that's when it erases, then reset the nes and try to load your save file. If your file is present then the ram chip and one of the diodes is likely okay. 

 

The diodes act like an analog or gate, allowing voltage from either the nes or the battery to power the ram while preventing the voltages from touching each other. The capacitor allows smooth voltage transition to prevent accidental erasure. One resistor regulates battery current and the other disables the chip when powered off to prevent unwanted writes.

 

I'll try and remember to measure some diodes for you when I get home. 

[2600Ibarelyknewher]

2 hours ago, emerson said:

If you remove the battery and save to ram, the save file should be present as long as the nes provides power to the cartridge. The file will erase once you turn the nes off. Hitting the reset button should not erase the ram.

 

If you want to test if the ram chip is okay, I suggest removing the battery and creating a save file, let the nes sit on for 10-15 minutes since you say that's when it erases, then reset the nes and try to load your save file. If your file is present then the ram chip and one of the diodes is likely okay. 

 

The diodes act like an analog or gate, allowing voltage from either the nes or the battery to power the ram while preventing the voltages from touching each other. The capacitor allows smooth voltage transition to prevent accidental erasure. One resistor regulates battery current and the other disables the chip when powered off to prevent unwanted writes.

 

I'll try and remember to measure some diodes for you when I get home. 

I tried again without the battery and made a save then let the console sit On for 20 mins or more then reset it. The saves do stay, I suspect it’s a diode I burnt up down the line just not sure which one. I tested the battery itself and it’s sitting at 3.3v and 2.6v when it’s in the circuit. I appreciate your advise, I’ll replace a diode or two to fix this. I don’t think it’s the actual holder because it shows volts when in circuit. I guess my question is what to replace? Or test.

[emerson]

The battery measures 2.6v when it's in circuit?! The battery should measure near identical voltage whether it's in circuit or not. Something is definitely not right...

 

I measured the diodes on one of my boards. Resistance measurements were made with battery removed from circuit and striped leg of diode desoldered and lifted from circuit board. R-forward is with positive lead of meter on unmarked side of diode and negative lead on striped side, R-reverse with leads opposite. Vdrop is measured with the opposing power supply removed from the circuit. So when measuring the voltage across D1, the battery is installed and the cartridge is removed from the nes. When measuring the voltage across D2, remove the battery and have the cartridge powered by the nes. Measure voltage with positive lead of meter on unmarked side of diode and negative lead on striped side.

    R-forward    R-reverse	Vdrop
D1    662R        INFINITE	144mV
D2    664R        INFINITE	268mV

 

Note that while general purpose diodes would work in a pinch, the diodes on nes boards are schottky diodes. Further reading including diode replacement part numbers available on the nesdev forums: http://forums.nesdev.com/viewtopic.php?f=9&t=11279

 

In addition to what I said previous post, the resistor that disables the ram chip not only prevents unwanted writes but also puts the ram chip in a low current state. This allows the batteries to last as long as they do.

[2600Ibarelyknewher]

2 hours ago, emerson said:

The battery measures 2.6v when it's in circuit?! The battery should measure near identical voltage whether it's in circuit or not. Something is definitely not right...

 

I measured the diodes on one of my boards. Resistance measurements were made with battery removed from circuit and striped leg of diode desoldered and lifted from circuit board. R-forward is with positive lead of meter on unmarked side of diode and negative lead on striped side, R-reverse with leads opposite. Vdrop is measured with the opposing power supply removed from the circuit. So when measuring the voltage across D1, the battery is installed and the cartridge is removed from the nes. When measuring the voltage across D2, remove the battery and have the cartridge powered by the nes. Measure voltage with positive lead of meter on unmarked side of diode and negative lead on striped side.

    R-forward    R-reverse	Vdrop
D1    662R        INFINITE	144mV
D2    664R        INFINITE	268mV

 

Note that while general purpose diodes would work in a pinch, the diodes on nes boards are schottky diodes. Further reading including diode replacement part numbers available on the nesdev forums: http://forums.nesdev.com/viewtopic.php?f=9&t=11279

 

In addition to what I said previous post, the resistor that disables the ram chip not only prevents unwanted writes but also puts the ram chip in a low current state. This allows the batteries to last as long as they do.

Well I finally figured out the issue....hahah what a head ache. I’m almost too embarrassed to say it on here lol but you guys deserve to know. I realized that super glue got onto the back of the battery where the negative terminal touches it, such a small amount I could barely see it. This super glue made it so the connection between the battery and the terminal was not good at best. I’m glad to have this forum for help because it occurred to me when you mentioned 2.6v was odd even in circuit. This is a great resource for anyone DON’T USE SUPER GLUE AROUND ELECTRICAL CONNECTIONS.

Edited September 15, 2020 by 2600Ibarelyknewher