Electronics Projects General - DIY, Repair, and Help

[WelperHelper99]

Thank you for your help, kind sir. Google and Duckduckgo were both absolutely useless in answering this question.

I'd recommend testing it first to make sure they aren't super batteries, a cheap light or something, but they sound like normal AAA batteries.

 

[seri0us]

Modded my headphones so I can finally swap cables as I please, however leaving a little bit of the original cable coming out of it and putting the port there because making an appropriate sized hole and soldering that close to a driver is at a level I'm not quite ready for yet.

 

[WelperHelper99]

Modded my headphones so I can finally swap cables as I please, however leaving a little bit of the original cable coming out of it and putting the port there because making an appropriate sized hole and soldering that close to a driver is at a level I'm not quite ready for yet.

I've had a few Xbox headphones die, not because the speakers went out, but that the cables fragged themselves. Good job man, good job.

Also might be updating my old man's PC I built for him soon. He wants two screens. I'm probably gonna trawl a thrift store or two for a basic bitch 1080p screen, find a old HDMI cable to go along with it, or just buy a two pack online since I've wanted some spare cables for myself.

 

[gildersleeve]

My close family is moving out of town. So I'm helping them pack and I'm going through my stored computer collection in the basement to bring to my current residence.
Pulled out my Amiga 2000 and prayed that the clock battery didn't destroy the motherboard in the intervening 13 years it's been sitting (it didn't, and it's snipped off now) however there's some interesting texturing on the PCB that I've never seen before. Could someone identify it? I will pay you in video toaster 2000 3D renders once I have it set up again.

 

[DavidS877]

My close family is moving out of town. So I'm helping them pack and I'm going through my stored computer collection in the basement to bring to my current residence.
Pulled out my Amiga 2000 and prayed that the clock battery didn't destroy the motherboard in the intervening 13 years it's been sitting (it didn't, and it's snipped off now) however there's some interesting texturing on the PCB that I've never seen before. Could someone identify it? I will pay you in video toaster 2000 3D renders once I have it set up again.

Just looks like the solder mask is lifting, could have been moisture but I'm not seeing any corrosion, might just have been poorly applied at the factory, maybe not rated for this many years.

I assume you're checking with the actual Amiga people for any other recommendations before powering it up.

 

[gildersleeve]

Just looks like the solder mask is lifting, could have been moisture but I'm not seeing any corrosion, might just have been poorly applied at the factory, maybe not rated for this many years.

I assume you're checking with the actual Amiga people for any other recommendations before powering it up.

Oh yeah, I'm going to be replacing the caps. Checking continuity, pulling the chips and making sure the seats are clean. I hadn't seen a PCB do that before. Along with making sure the PSU is aok before slapping it back together. It shouldnt be much worse to do than the vic20 I pulled out of a hoarders house covered in rat shit/piss and concentrated hanta virus.

What I'm really excited for is the GVP 030 accelerator + IDE controller. Back when I got it none of the software was available and the disk that had the software was corrupted. Now it's online and I can get it fully functional again. I'm wanting to get a new kickstart rom so I can plop on workbench 3.1. Find a network card or have my raspberry pi run a dial up connection to the modem I have for it. Maybe try that "time machine" software that uses the wayback machine to serve of era websites of whatever date you chose onto of era hardware.

 

[AmpleApricots]

Oh yeah, I'm going to be replacing the caps.

In that time the solder masks and manufacturing processess weren't as perfect as they are now. There's probably tin on the copper layer under that area of the soldering mask. The solder mask might come off very easily there, but it's cosmetic and the copper is protected by the tin, which isn't very reactive and won't really be affected by moisture etc. nearly as much as the blank copper would be. It's sometimes hard to tell from one picture, but that does not look like corrosion or damage. Check if any ICs and passive elements have anything green on them.

From memory:

Capacitors I wouldn't bother replacing on these old A2000 boards, they're probably still good to go. I would replace all capacitors in the power supply though, if you trust yourself to do that. You might want to replace the X capacitor too, while you're at it, some of them in power supplies of that vintage are prone to failing and that's not very safe and also unpleasant (very bad smelling, scary smoke) if it happens. If you have one of the older Amiga 2000s, the power supply will be made in (west)germany or england. I would keep that power supply, it's built like a tank and after a recap will easily last another 40 years. (Not power efficient though) The later ones are made in china, and nothing special. The early power supplies had capacitors that were prone to failing after ~5 years, there was something wrong with them, so it's kinda important to replace them, there's no POWER_OK or anything like that (like in ATX) in these power supplies and it can totally damage your Amiga if they don't work correctly. Also when testing, don't turn it on if it's not connected to a user, (mainboard, old filament bulb etc.) it can break the power supply.

I think in the older style power supply the net filter (x cap) was integrated into the power plug. I could probably get you a spare part number if that's the case for you.

While you're at it and think about replacing the fan with a quieter one, be aware that IIRC it wasn't a normal 12V fan in the early power supplies, but a 110V one. Contrary to modern power supplies, the 12V rail is more of an appendix in these and basically used for almost nothing, so you can't put a big load on them. If you really have a video toaster, you kinda want to keep the original power supply as the Amiga derives the TICK signal from the power networks' frequency from it. There are better solutions for that today though and it's not a total showstopper if you wanna replace it, as you probably don't plan to synchronize to late 80s studio equipment. The Video Toaster is very touchy about that signal missing though and some of the older A2000 boards also need to have a jumper set if the signal is missing IIRC.

Re: 12V. Modern power supplies are regulated around 12V and that's their main line because of modern point-of-load reagulation, this old Amiga supply is all about +5V. If after reading all this you plan on replacing it with a modern power supply, be aware that this is not ideal for the modern power supply, as in most modern supplies the +5V is the appendix for legacy purposes, and it actually might not deliver enough ampere in a fully-expanded A2000. It's also a very bad way to run a modern supply with no load on the +12V and all the load on those +5V and it's not good for it. The negative voltages these computers needed for some exotic purposes (e.g. modem) are also usually missing in modern supplies, and there might be lots of ripple on the +5V the different revisions of A2000 mainboard are not good at catching.

Good machines. First computer I owned, bought it in 1987. Mine is still in working order and has a Merlin graphics card and a Blizzard 2060. Ran a BBS on it in the 90s. Desktop cases are where it's at.

 

[WelperHelper99]

A small project, but helping my friend that just moved into his new place hook up his old Wii and Xbox 360. We needed a composite splitter and cable, and I wanted to leave open the remaining HDMI port on the TV, so I bought that for him since his wallet is hurting from the move. He'll have one port in the splitter left open, so there's expansion room for he and his roommates.

 

[RIFA Capacitor]

I need some help, if anyone has any expertise with old CRT PVM monitors.

I have a Sony PVM-1340, and it turns on, the tube warms up, audio comes through the speakers (if something is hooked up to it), but I can't get video to display. I've tried every input it has (s-video, RGB, composite) and none of them result in any video.

I can go into detail on all the troubleshooting I've done to this effect later, but right now I want to know if anyone has the schematics for this model of CRT. I was able to find (and somewhat use) the schematics from a PVM-1341, but there's small differences on the main board that make it not quite accurate, and the video input board is completely different.

I can also provide pictures of my actual set (stock photo below for reference) if anyone needs to know more.

 

[Thirsty Kitty]

Hey guys, I'm currently working on building an ROV over the summer, and I have a question about brushless motors. As far as I've read online, water wont explicitly damage the motor, is this true? Just making sure before I accidentally piss away a motor, they don't make those fuckers cheap.

 

[Si vis pacem para bellum]

I really like these practice kits you can buy. They're cheap and you won't worry too much about fucking an actual board up with them.
View attachment 5044854
There's a ton of different practice soldering boards out there to choose from, so I'd take a look if you haven't already.


Thank you, this gives me a lot to think about and do more research on. At least I feel like there are options now.

I do those kits with my kids, I build models (and sometimes sell them), and they often are blown away when there's batteries, motors, or LEDs in them. The kits are very accessible, and if you accompany them with something like the Khanacademy lesson on electrical engineering you can get quite the accelerated jump into the topic.

 

[Polock]

I am beginning to acquire a lot of doodads that run on 18650 batteries. I have a chintzy charger that hooks up via USB-C but it sucks. I know I could get a wall charger to charge multiple batteries, but I have a cunning plan.

In my possession is a very nice charger that I use for 4-6s LiPo drone batteries (Toolkit Q6AC). I would like to use it to charge my Li-ion batteries in series. I would also like to be able to charge however many I want to at once - up to 6.

The three main benefits I see would be that it should charge them much faster, I can monitor the health of the batteries via their internal resistance, and I can discharge them to storage voltages or as a makeshift battery pack.

The main problem is that as far as I can tell, all series/parallel charging boards are designed for wired up LiPo battery packs, not naked Li-ion 18650's. Also I am not an electrical engineer, I'm just a retard on the internet. I'm only attempting this project because it seems fairly simple to assemble.



This is my proposed diagram. If it works like I intend, it should be able to charge in series as long as I load from the top to the bottom.

I am aware that the somewhat exposed battery contacts in their holders are a potential safety hazard but other than that and the inherent risks involving batteries am I missing something? Am I about to burn my house down?

 

[Polock]

[FIRE HAZARD]

Ok I made a revision, slightly simplified it as well. I can only charge in multiples of 2 but that's fine.


Load balancer connectors on the left, main power connector on the right. Cells are 18650's.

 

[NortelNutworks]

Ok I made a revision.

Is this your first attempt at any electronics design project? It might be a good idea to learn the basics on something with a less explosive personality.

What's going on with the connectors on the left?

 

[Polock]

Is this your first attempt at any electronics design project?

Yeah, more or less.

It might be a good idea to learn the basics on something with a less explosive personality.

I GUESS.

However I'd rather learn on a project that I have a practical use for, rather than a dinky circuit with a switch and a light bulb.

What's going on with the connectors on the left?

Those are the connectors for the load balancer for the charger I have. All I'm making is a modular (and temporary) battery.

 

[Le b0wski]

I am aware that the somewhat exposed battery contacts in their holders are a potential safety hazard but other than that and the inherent risks involving batteries am I missing something? Am I about to burn my house down?

The main thing with 18650s is to be really aware that when connecting them together to charge(or for any reason) that they will want to equalize voltage. If you just connect 2 with the standard 5v 1A wall/usb it's typically safe as you won't get anywhere near overloading any single cell with it.

Once you have 3 or 4 cells involved you get the situation where multiple cells with a higher charge/voltage can dump into a single cell. The more cells you connect at once the worse this potential is, it's how most of the ebike/scooter battery fires happen.



The other similar situation is different battery chemistry since 18650 is a physical size and they can be dozens of different formulas with no real way of knowing. So you throw a handful of one chemistry in and just one of another, they start to charge fine so you think nothing of it. As they charge the curve is different, one peaks at 4.2v and the rest at 4.5v so at 4.3v they all start to dump into the 4.2v with explosive results.

Honestly for safety I really would just spend the relatively small amount to just buy a charger for them.

 

[Le b0wski]

However I'd rather learn on a project that I have a practical use for, rather than a dinky circuit with a switch and a light bulb.

If you want to do it with relative safety then they sell TP4056 boards(the blue ones in the pic) for next to nothing. 3d print or make your 1 cell battery holders and then just wire up each board with 1x 18650 off a common rail. Very common project with plenty of support/guide videos.



Just then continue to be aware of balancing when you take the cells out and put them in other things.

 

[FamicomGorby]

I guess as someone that repairs electronics regularly, mainly old arcade and pinball crap, the number one investment is a decent temperature controlled soldering iron. I use a Weller WS51, which apparently has doubled in price on Amazon for some reason. Regardless being able to maintain an exact temperature just helps a ton when soldering and helps prevent fucking up PCB's and lifting pads and what not.

Also get a solder sucker. Like a $100 compared to $8 for a pump or whatever but way less chance of solder flakes getting everywhere and shorting stuff on old unmasked PCB's.

 

[DavidS877]

I guess as someone that repairs electronics regularly, mainly old arcade and pinball crap, the number one investment is a decent temperature controlled soldering iron. I use a Weller WS51, which apparently has doubled in price on Amazon for some reason. Regardless being able to maintain an exact temperature just helps a ton when soldering and helps prevent fucking up PCB's and lifting pads and what not.

I find the PINECIL(and some similar models) to be a good alternative to my Hakko and keep one at my desk for quick stuff when I don't want to walk to the garage to use the 'good' stuff. It's loads better than my old RadioShack iron and about the same price for those on a budget.

If you're made of money a butane iron is a nice 2nd or 3rd iron too for portable use and interchangable tips for heat shrink.

 

[Narcan Nimrod]

Ok I made a revision, slightly simplified it as well. I can only charge in multiples of 2 but that's fine.
View attachment 7594601

Load balancer connectors on the left, main power connector on the right. Cells are 18650's.

The part that makes this dumb is putting them in series. They will charge unevenly as a series system. Vehicles with series twelve volts for twenty four volt cranking amps have this exact same issue, (the batteries are charged as twenty four volts but deviate in charge individually.) Run them in parallel and you will not have this problem. Add a resistor(s) if you have to lower the voltage. but as it stands you are inventing problems for no reason. If i have to explain the danger to not knowing what your batteries are doing? you should not be doing this.