Some true asshole manufacturers store critical data in a prom. They solder the batteries in and if you remove them and it loses power the prom clears bricking the device. C/KU band satellite receivers do this. As well as many older cable tv boxes. I used to repair them and had bench power supplies to keep the prom alive during repair. At the end of my run with the cable industry I had started cloning the proms and replacing the information that they stored there.
Not even soldered, but spot-welded. Still ‘not field replaceable’ sounds like a challenge to me. I be with some wirecutters, some solder, and a little bit of wire that battery can be easily replaced.
I’ve found the little flush cutters that came with my Ender3s are awesome for removing stuff that’s been spot-welded like this. I took apart a few cordless tool packs with them, and kept everything so neat I could easily reuse all the tabs if I wanted.
Relevant fact: Most standard non-letter batteries are named after their physical size, for example a CR2032 is 20mm diameter x 3.2mm height; or not a button battery, but an 18650 is 18mm diameter x 65.0mm height.
As far as what battery it is, measure it in metric. (mm) Search up a button battery chart. One of those should have voltage and measurements you can compare against.
To go further, all those 3v button batteries are essentially the same. You can buy any one of similar thickness to replace one like that, that you will have to re-solder in place. It’s definitely a 20mm across one, so the first numbers will be 20. For thickness I’m guessing by the looks of it, it’s either 3.5mm thick or 4.0mm thick, so last two numbers will be 35 or 40. So you want either a 2035 or a 2040 as a replacement.
They’re all 3v. The only difference in button style batteries thickness is how much capacity they hold. If it physically fits in a device and you can create the connection for the top and bottom, it will work. I’ve used a little piece of metal or wire to bridge a gap to make a thinner battery replace what was supposed to be a thicker one if I didn’t have the right size on hand. Just means it will die a bit sooner.
Maybe. It’s a thin looking clip and not soldered to the board very strong. Prolly be OK if op can remove the battery without the clip breaking from the board. I’m guessing it will come off when op tries to pry those spot welds off the battery.
When the time comes to replace soldered in batteries, (optional) snip off the leads, remove the remaining leads with a soldering iron and replace with whatever is handy.
Speaking from the experience of replacing lots of soldered in batteries in devices with high downtime and understanding the design and function of rtc backup batteries in telecom equipment and specifically spending months cleaning and refurbishing old telecom equipment for resale, Nintendo cartridges need replacement batteries, not switches.
The battery is only backing up the rtc when the power is off. Telecommunications equipment is high uptime and shouldn’t ever even see an outage as long as Pokémon emerald.
First things first: it is replaceable. I outlined how to replace it.
Second, the battery doesn’t define the lifespan of the equipment. The upgrade cycle it’s designed around defines the lifespan of the equipment.
But let’s say it didn’t. Let’s figure out how to make an rtc battery field replaceable:
It will need an access panel and a battery holder. We’ll need to limit out selection of battery chemistry to those that don’t corrode around the contacts. We gotta standardize the location and type of battery so that means standardizing the type of rtc circuit and since the whole point of choosing a replaceable battery is to lengthen the life of the equipment, we need to pick a rtc circuit with a long design life too and integrate that choice into all our future designs. I say that because most of the time nowadays there’s so much stuff on any given board that you gotta go out of your way to get a pcb that doesn’t already have some kind of rtc integrated into some kind of chip you picked for a different reason somewhere.
Now let’s put our battery door on. Wait a minute, this things 1u. The front panels all the way out because it’s taken up by 48 Ethernet jacks, six leds, two usbs, two fcs, two more ethernets, a serial port, a button and somehow a corporate logo around the edge. Okay let’s turn it around: crud, all taken up by two huge bus connectors, two power supplies and their vents, two power inlets, the quick release tabs for the power supplies and bus connectors, the mandated visible ul/health and safety sticker and another fan grille.
Guess we’ll have to put it on the other sides. No big deal, just isolate the place on the pcb that the battery holder sits on so its standards compliant, add a few plasma cuts and a dimple to the machining steps for that panel and add a little plastic door (captive with a screw or hinge so it can’t be lost) and we’re done!
Except we just made it worse.
Imagine going to replace that battery. It’s field replaceable, right? So what’s that process? Oh it’s real straightforward, you just bring down or reroute the systems reliant on the unit, unplug 48 Ethernet jacks, two usbs, two fcs, two more ethernets, a serial port, two bus connectors from the back, and two power inlets from the back, pull it out of the rack, unscrew the battery door, replace the battery, put it back in the rack, plug in 48 Ethernet jacks, two usbs, two fcs, two more ethernets, a serial port, two bus connectors into the back, and two power inlets into the back, turn it on, securely set the rtc (this is incredibly important!) and reroute systems back to it or bring them back up.
And if nothing goes wrong, if we didn’t damage a connector or receptacle, drop something or catch an esd event then we just doubled the lifespan of our device!
Except we didn’t. The battery had a ten year service life in this environment, and we replaced it at nine to be safe. Cisco though, stopped releasing security patches too, so now our router has ten new years of being unavoidably owned by every sk the world over.
Well, if we just went through all that work, probably the firmware policy would be updated and the support window lengthened to match, right? So now they’re pushing security patches for 20 years! Certainly that cost won’t be borne by the customer and we’ll be rewarded for our good design work!
On a gigabit router. For the rack mount environment.
And we also have a standard rtc and battery type to integrate into all future designs, training material and equipment.
I didn’t just waste thirty minutes of a day off writing that up to make fun of you, but to illustrate how the conditions under which specifically telecommunications equipment operates, is designed and managed dictate what decisions the designer makes about stuff like rtc backup batteries, which are a security feature btw.
If we had say, a planned economy, we could expect devices like these to be designed with a longer lifespan and an extant recycling process in mind. Under our current system that’s just not possible.
There doesn’t need to be a separate access panel. It can just be in a normal battery holder like so: https://imgur.com/a/Zur6G0x Replaceable CR1225 in Cisco 1802
Considering it’s something that generally runs 24/7 for years, it may still be a good idea to clean out dust from the device when possible. That’s also an opportunity to replace the RTC battery, assuming it’s replaceable. Oh, hey, it seems Cisco even used to provide some Li batteries until 2017.
Also, not all businesses need the networks up 24/7. There may be plenty of time for down time for maintenance.
The eos on that 1802 was 2018. They stopped selling batteries for it a year before it stopped being supported. They claimed in that bulletin it was because of the shipping restrictions on batteries (which I believe!) too, so that might have had something to do with the series of decisions that led to soldered in batteries.
I didn’t even think of shipping restrictions making it prohibitively expensive to ship replacement batteries. That’s a good one.
Since you’re the op, how do you handle soldered in batteries? As you might expect from my replies, I just unsolder em (with a bench supply tacked in to keep power going to the circuit) and put in a replacement. Usually I don’t even put in battery holders, just another soldered in cell of the same type.
On another note, as is said here https://lemmy.world/comment/10316824 some devices clears the rom when the battery is removed, effectively making the battery's life, the device's life. THIS is true asshole design.
EDIT uhm, didn't see this was an old thread.
if you want to preserve the clock memory then use an ungrounded soldering iron. Usualy the cheaper ones are ungrounded and the midlevel ones are grounded. expensive or micro stations will sometimes have a ground lift switch. if you use a grounded one it’ll run a chance of getting into a fight with your bench supply over weather 3v gets to be at the node youre soldering.
Good luck. if you find that the through holes are too small to get good heat transfer, don’t be afraid to leave a 3/8" or so bit of the old leads sticking out and solder your replacement onto them. covered with heat shrink they’ll be fine.
they make low acid or non corrosive or whatever hot glue to attach that little toilet lookin’ doohickey for just these applications.
If you think that’s bad, some old arcade cabinets had suicide batteries. Their only purpose was to keep a sram chip alive that held a decryption key. Battery dies? No more game for you.
Its not about knowing everything. You can know a lot but don’t have the skills. Cisco doesn’t make cheap products and screwing it up, it not good. Especially it can be easily done at the factory. Its not like it would cost them much more. I can get a holder for like 0.50 to 1€ per piece. There you must subtract 19% VAT and think in bigger quantities. On a per device basis, its not adding much.
They do this, because it adds up and they can save a lot of money. They make more money when a customer pays for a replacement or when a customer screw things up and needs to buy a new device. Its not something companies should be allowed to do. Also it would be even better if we don’t need to tell companies what they should do and they do it themselves. In fact a lot do this, because it doesn’t add much to the total cost of one device, but it makes the product better.
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