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A tale from the trenches fixing an NES (debugger.medium.com)
100 points by pslattery on Oct 26, 2020 | hide | past | favorite | 53 comments



On the subject of right to repair: Back when slide out keyboards were still available I bought I a new Verizon phone and paid for the best insurance plan I could get. After a short amount of time my brand new phone just stopped working, the insurance said it was a factory issue, I sent it in for repairs. They couldn't fix it so they sent back a certified refurbished phone. It wasn't the same quality, the new keyboard was clicky and the refurbished felt spongy. I called to complain but I ended up in a support loop getting passed around in a circle of people who had no authority to fix my situation. I paid for a new phone with full insurance like a good little consumer and got a used phone.

Ever since then I buy budget phones; phone insurance is a scam, phones are intentionally difficult to repair, and I don't want to spend $1k on something fragile that I keep in my pocket that has a high likelihood of being dropped on accident and the only recourse being whatever policy Apple has to benefit itself. I wish we lived in a world where consumer electronics were owned by the user. A 30 year old NES can hold value, I have doubts about what 30 year old smart phones will look like.


I've been pretty happy with paying for applecare on my iphone. It's saved me money a few times, and the one time I cheaped out and didn't buy it, I got burned.


Nicely done. I restore and 'upgrade' NES consoles as a hobby. Most of these steps feature good restoration techniques. However, for anyone here looking to do the same, please skip the polyurethane step. While it may impede corrosion, that step makes the system much harder to repair/modify in the future.


Is there — as Julian Baumgartner would say — an “archival-grade reversible isolation-layer varnish” that could be applied in place of poly sealant? Silicone, maybe?


Would shellac work or traditional lacquer[0] work? They both cure by drying, not polymerizing, and can be removed decades later with the original solvent: alcohol in the case of shellac, or lacquer thinner in the case of lacquer.

I haven't had any experience with lacquer because traditional lacquers almost have to be sprayed, which I am not equipped to do. I have plenty of experience with shellac because you can brush it and get a pretty decent finish off the brush, or French polish for a more refined finish. French polishing takes advantage of the aforementioned properties of shellac: besides laying another thin layer down, you're also redisolving the existing layers and smoothing them as you go.

Traditional varnishes cure by polymerization, and generally cannot be removed with mineral spirits. That isn't to say you won't ruin the finish trying, but you'll need a different solvent if you want it gone cleanly.

[0] lacquer has become an almost meaningless term. There are products that might or might not technically be lacquer that are called lacquer or water borne lacquer or some other phrase that includes the word. I'm referring to the stuff that uses lacquer thinner for the solvent. You'll know it if you smell it: it smells like it's giving you cancer right now, not in 30 years.


Mind you, in this case, we're talking about something that 1. doesn't have to dry clear (and in fact can dry entirely opaque), and where 2. it'd be much better if you could remove it by peeling it up, rather than by using a solvent, because many of the components have plastic housings that don't take kindly to, well, any strong solvent really. The goal isn't an art piece — it's to create a barrier to moisture/corrosion for a board within an unlit box. If you want to do a repair, you'd entirely remove this layer before doing it; and entirely reapply it afterward.


How hard would the peeling be? I'd worry about ripping off components or even board traces if I had to peel something like that off it.


Shellac ought to be fine. Alcohol isn't going to cause problems for any of the components when you remove it, but lacquer thinner seems like it could.


Shellac has nearly zero resistance to water vapor so it wouldn’t prevent corrosion at all. Nitrocellulose lacquer isn’t a lot better.


Any general purpose conformal coating is fine. I don't understand why it'd make repair more difficult. Most of them can be soldered through directly, or you can use thinners or strippers to remove them.

If you want silicone you can find it. Here's one example: https://uk.farnell.com/mg-chemicals/422b-340g/chemical-coati...


I'm curious why the conformal coating was added to the bottom of the PCB, it didn't seem at all corroded after 30 years. On the other hand, I'm surprised they didn't replace all the electrolytic capacitors in the A/V area -- or even the whole unit. If some of those leaked already, IMO, the rest will leak soon too. Seems a bigger risk than a lack of conformal coating. shrug

Either way, excellent video and very well put together. I love seeing stuff like this.


Sure, we all want the right to repair, but don't we realize that easily repairable devices could add as much as 1 to 2 mm of thickness to our phones? Sure, my Galaxy Note 2 had a replaceable battery and a shattered screen the local repair shop could fix for $50, but I paid for that with more than 0.5mm in additional device thickness than my current phone.


Want things to change?

Stop having reviewers point out that extra couple mm as being a "glaring design flaw" or comment on "how extra chunky" the phone is.

FWIW rugged, durable, battery replaceable devices have repeatedly failed on the market. Notably, Motorola tried, and failed. Everyone bought Samsungs.


Alright, I'll do that..? With all the influence I have on this worlds' reviewers.


My point is that device manufacturers are responding to the pressures they are given.

And it isn't like there are very many phone reviewers for any given market. If someone wanted to organize a letter writing campaign to try and convince the top 5 or 10 phone reviewers to just not mention device thickness that just might have an effect.

(On the flip side reviewers complained about the removal of the headphone jack and that didn't help any so...)

The other thing to remember is that with modern battery charging tech, batteries can last a long time. Samsung is the best in this regard, their chargers are really smart and work hard to preserve battery life.


I certainly don't have numbers to back it up but I'd guess WAY more purchase (or not) decisions come from holding phones in hands rather than reviewers complaining about a phone being too thick.


"Right to repair" isn't really a universally fixed idea in its details, but one interpretation could be that a company needs to provide access to spare parts and documents to support repair by unaffiliated 3rd parties. That would not necessarily mean that the company would need to make their devices easily repairable (by for example making batteries replaceable), but instead require the companies to support unaffiliated 3rd parties in their repairing endeavors similarly to how they would do it internally. In a scheme like this, there would be nothing standing in the way of continuing to make thin devices.

That said, I do personally wish there were some sort of "minimum repairability" that would potentially put limits on how thin something can be if that made repair much more difficult, but that's a bit of a side-issue to "right to repair" for me.


It's amusing - I like light laptops but at this point I'd prefer an artificially deep case just so they could get some key-travel back in. For portability of a laptop the width really isn't a consideration... For phones and tablets ditto.



Serious grammar question...

Is the "an" in the title proper because NES, pronounced, sounds like /ɛn/, even though it's actually a consonant?


It just depends on how you say the initialism. If you say "ness" then you'd use "a". If you say "en ee ess" then you'd use "an".


The "ness" pronunciation is chiefly used by Brits (who also tend to pronounce SNES as "snezz").


Canadian here... ness all the way.


Canadian here. N E S all the way. You must be french.


This is absolutely horrifying


'an' is used when the sound of the next letter is the sound of a vowel, so in the case of eN-E-S, 'an' is correct.

In english multiple vowels in a row cause you to take a pause, which is why the -n is added

Worth noting, the other posters are correct in saying that 'a snezz' or 'a ness' is also correct.


> I polished the filthy pins that connect the game cartridge to the mainboard

Does this work? I thought you might have a chance of success with bending the pins, but most of the time, replacement is the only viable option.

I did always wonder if you could electroplated the pins again in the right solution and voltage.


There is a tool designed to mechanically clean contacts called an electrical contact burnisher that its design makes it hard to use enough force to bend pins.


Possibly chemically with e.g. Deoxit instead of mechanically?


While I'm all for right to repair, repairability is a tradeoff.

Everybody seems to want a razor thin phone/laptop/whatever, which makes easy repairs impossible, and treats them as expendable anyway. If it's out of warranty it's obsolete.

The amount of labor to diagnose and replace a chip on a tightly packed motherboard sometimes exceeds the price to replace an entire motherboard.


It is all a matter of degree.

Consider what people want to repair. It is doubtful that many people would want to do chip level repairs due to the expense. People may want to replace things like keyboards and screens, which are easier to work with since they are independent modules. If people started using their devices for longer periods of times, the battery would likely be a candidate.

Similarly with design. People may desire thin and light, but what is the point where no one will care or notice (short of bragging rights based upon advertising literature rather than utility)?

It is also worth noting that thin and light does not imply that easy repairs are impossible. Companies may try to convince people that the interiors of our devices are bursting at the seams with sophisticated electronics, but the reality is that the screen often dictates the size while the internal PCB uses a fraction of that space. (I have seen thin phones that are screwed together, have user accessible batteries and microSD slots, and even had a snap on panel to hide all of that. Laptops aren't all that different in this respect.)

Sure, they may be able to trim half a millimetre here and there by throwing repairability out the window. On the other hand, it is a high price and less of a trade-off than many will suggest.


That's all valid, but that's not what your typical consumer cares about.

Even with cars, manufacturers get away with things like removing an engine to replace glow plugs. With phones and laptops, very few people care if it's repairable. That's unfortunate but it's true.


This is such a red herring. I've got a Galaxy S4 here that is bricked with a bootloop, due a software error on the emmc chip. I know this is the case, because someone has done the painstaking work of investigating the bug on the S3, and hacking up a reverse engineered fix. I'm guessing it would take a week to retrace their steps on my model. Meanwhile if these devices were well documented by the manufacturers, it would be an easy no-solder repair.

Given both the complexity and the shoddy engineering of modern software/firmware, I wouldn't be surprised if the majority of "hardware" problems are similar.


On the topic of bricking, I had my $250 amazon kindle display the dreaded battery with exclamation mark a day after warranty expired. Coincidence? I contacted amazon and was kindly informed that there are no authrized repair facilities and amazon does not fix it. Was offered $5 to return it and 15% discount. Had to do a bit of research online but it turns out one can take it apart. I disconnected battery and reconnected it and it started charging again. I’m not a conspiracy theorist but this felt like amazon would software brick the device so I would buy new one due to timing of warranty. Disconnecting battery literally reset device. Anyone experience this?


What is a red herring? It's just not perceived by the public to be an issue.

If it was, it would be legislated just like car manufacturers are forced to carry parts for a number of years for every produced car.


The narrative that "razor thin" devices preclude repair. If I had the manufacturer's documentation, the problem with my S4 could likely be fixed with just a USB cable. Its physical form has nothing to do with its general lack of repairability.


They don't preclude repair but definitely make it harder to make modular, user serviceable devices.

Software repair is a different story of course, but it's another double-edged sword- you wouldn't like your phone's memory to be fully accessible with just a USB cable.

I can't imagine a mechanism that would only allow USB tampering only if the phone is malfunctioning.


Your phone's memory effectively is fully accessible with just a USB cable. I am unaware of any android phone which actually verifies the signature on its bootloader - run `adb fastboot flash` and you can load arbitrary ROMs onto arbitrary chips. The contents of the ROMs is what's secret.


You'll need more than a USB cable if you've bricked it, even fastboot won't be accessible.


> you wouldn't like your phone's memory to be fully accessible with just a USB cable

Use cryptographic authentication then, with a password/key provided to you when you buy the phone?


> Everybody seems to want a razor thin phone/laptop/whatever

Do they? I'd be much happier with a phone that was a little thicker and had a bigger and/or replaceable battery. Apple just doesn't want to sell me that.


Just blow on the cartridge and it'll work fine


Nooooooo you'll cause bitrot :(


I‘m not much of a handyman myself but I found the video fascinating to watch. Very impressive to see the before and after pics in comparison.


Restoring old electronics is a booming segment on YouTube. If you enjoyed that, there's a virtually endless supply to peruse.


Paywalled, requires a Medium upgraded account.


Open it in incognito/private mode. I use this plugin to always open medium pages in a new private tab: https://addons.mozilla.org/en-US/firefox/addon/temporary-con...


Not for me. Maybe you’ve hit your monthly “free article limit”?


So ironic given the content of the story.


I was able to read the text of the article fine. The images didn't load, but I know what a NES looks like so that didn't rise to the level of enabling Javascript.


Oddly fascinated by the booting speed of the NES!


Instant. No OS. Whatever address word you put into the 6502 reset vector ($FFFC/$FFFD) it will happily jump to on power up or reset and start chugging right along. The PPU (aka GPU) takes roughly 2 frames (33ms) to "warm up" and receive information, so, you want to wait for that by polling PPU_STATUS ($2002) with BIT and waiting for BVS twice when NMI fires. It is a good idea to disable decimal mode, disable audio IRQs, set the stack pointer, and zero the memory in a loop. Any booting and loading speed is entirely code dependent. https://wiki.nesdev.com/w/index.php/Init_code


This article is behind paywall. I wonder what is medium's business plan in the vast plain of so much interesting content to read for free.




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