2600Ibarelyknewher
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Posts posted by 2600Ibarelyknewher
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Does anyone know the volts, milliamps and the polarity of the original Gemini power supply? Also is it DC or AC?
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Just wanted to say thanks to all who have helped me in here, appreciate all the good advice.
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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 268mVNote 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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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11 minutes ago, tpugmire said:
I don’t have a picture, it wasn’t mine, my younger cousin tried to fix it himself and screwed it up. He ripped off an entire solder pad and some of the trace. It was Pokémon Emerald.
I’ve done quite a few GBA and GB Pokémon games, I find them much easier than the through hole snes and nes games etc.
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1 hour ago, R.Cade said:
It's not really damaged, just very very sloppy. Get a better soldering iron, solder, and flux. Practice on some old board.
Redo this when you do.I don't know why you have jumper wires, the tracks look fine to me.
I have an O.K iron but I was in a rush when doing this because it made me upset thinking about why I had done to this game lol, the next time I do something like this I’ll take my time and practice some before hand. I use leaded solder so it typically melts better than this, my current solder is def really cheap though lol. I tried just soldering batteries and also holders with just using the original traces but the game wouldn’t hold a save anymore. Once I added the cables it could hold a save.
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1 hour ago, tpugmire said:
I fixed a GBA game that had almost the exact same thing happen. Didn’t look pretty, but it worked. That’s the important thing.
I was wondering about that, since it wasn’t through hole, was it harder to fix? I’d love to see a picture of that actually I’d bet it was a Pokémon game.
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have you ever done anything like this lol?
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1 hour ago, Keatah said:
All the time. I start organizing files or my computer stuff and hardware and stuff and I get a 3rd of the way through and discover a better way. Get pissed. Stop. Revisit. And on and on it goes! Meanwhile the shit keeps piling up!
I think I truly just thought I messed it up so badly I couldn’t fix it lol. I didn’t have anything to go off of. When I google this problem of pads gone it was too general of an issue. Most people are fixing non through hole devices. Two months this thing sat on my bench lol, 5 different attempts. Now I know to ask you guys when I am stuck.
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6 minutes ago, wongojack said:
If it works, it doesn't matter how it looks.
Some general advice would be to "heat the work not the solder." So you put components in place then push your iron against and wait. When the work gets hot, you can apply solder and everything should fuse together in a smooth liquidy pool that cools as soon as you remove your iron. It looks like you probably could have waited a little longer before applying solder.
Do you think its because I tried to pile it on too much? Lol I’m just so happy it works, I thought for sure I really messed it up for about 2 months. I’ve done about 15 of these battery changes and this one went really badly for some reason. The board just didn’t take the heat as well as other games I’ve seen. That’s part of the reason I’m scared to bring the heat to it. I have a soldering station and reworks station attached. You ever just mess up really bad and avoid something for a time because of it lol?
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Give me your honest opinions lol
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54 minutes ago, wongojack said:
This is totally fixable, but you won't get perfect step by step instructions from anyone. Here's my advice - don't take any advice without testing it yourself.
Step 0 - Get a different copy of the same cartridge
Step 1 - Buy a Multimeter
Step 2 - Do a conductivity test (aka short; aka "beep") around the missing components and compare to the "good" copy
Figure out how they were supposed to connect before this thing got ripped outta there. Your job is now to essentially restore the connections that were there before. As Keatah says, it will take work on both sides of the board. The advice you've been given is
A. Install a battery holder - this should cover the gaping wounds on the top side of the board <- this is on the front
B. Hook it to the next component in line - aka restore the connections that were there before <- this is likely on the back
Only someone with the thing in their hands inspecting the current damage will know exactly how to put this back together. You can figure it out if you take a breath and do some inspection before, during, and after your work.
About diodes - they are used to restrict polarity to a specific charge in a circuit. Basically, they only let electrons flow in one direction. They are usually there to prevent some sort of accidental reverse polarity from flowing to components. In this case, I would assume the positive voltage from the battery would be connected to the positive end of the diode and then current would flow from there to the rest of the board. Diodes are marked with a dark band near the far edge of one side of their cylinder. This is called the "cathode terminal." Connect positive voltage to the terminal farthest from the dark band. In this case, I think if you got the connection reversed, it would just mean you'd be bypassing the diode and send the battery voltage straight to the board. It would probably work both ways. BUT - I would test everything I am saying for yourself because I'm just a doofus on a website multi-tasking and nothing happens to me if your game is damaged even more.
Thanks so much for the multi meter suggestion, I honestly am not the best at electronics lol, I thought it energized the whole board not just parts going specifically from the terminals to parts on the board. I’ve found where the terminals were suppose to go ie one of the diode legs and one chip leg for the NEG terminal. 15 mins it’s held a save for! Thanks so much
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17 minutes ago, Keatah said:
Front and back.
Sorry I’m confused, could you rephrase this? If I soldered a tabbed battery or holder, would I just need to connect the positive side on the back to the diode? Also where on the diode is best?
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8 minutes ago, Keatah said:
In this case no. You won't even need the conductive pen. Just solder-up both sides!
You mean the Negative and positive side of the battery? Only
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18 minutes ago, tpugmire said:
I’d put a battery holder in this now, because it’ll be hard for anyone to change the battery it the future. Just solder a small jumper wire from the back side of the battery terminal and hook it to the next component in line, which looks like the diode at the top of the board.
The front pad is also damaged too, does this make a difference?
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Hey guys, so this time I messed up bad, no excuses here. Simply how can I fix this. Also will the product pictured below which is an conductive epoxy help? The game is Zelda for NES.
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Coleco Gemini Power supply
in Hardware
Posted · Edited by 2600Ibarelyknewher
Thanks so much, I was able to look around my house for an alternative and I realized after looking at this picture that an Atari 2600 power supply is the exact same specifications. I guess I should of know since it was a copy.