Today, a laserdisc player from the thrift store somehow fell into my hands and made it home with me. I know next to nothing about this format, except that it was a relatively uncommon format that managed to stick around for 30 years.
It powers on and plays audio CDs, but I don't have any laserdiscs to test on it. Is there anything important I should know before dropping a bunch of money on this?
Last week, I noticed that some of the counters in my computer would count multiple times per clock cycle, and it caused my programs to not run properly. I did some research and found that switching noise from the control logic EEPROMs on the half signal can cause the clock to pulse multiple times during one cycle. Disconnecting the half signal from the EEPROM and tying it low fixed the issue.
A few days ago, I wanted to make the halt instruction work again. I read a post about this issue from a few years ago, and the solution the person came up with was latching the halt signal on the next clock cycle. I decided to do this by using a 74LS74. Unfortunately, my computer now randomly halts.
What's strange is that it always halts during the same instruction at the same step. It doesn't halt every time it executes that instruction, but it never halts on any other instructions. That step does not trigger the halt signal in any of the instructions I have programmed in my microcode EEPROMs.
I've already tried adding pull down resistors to the input of the latch, but it didn't help. I'm running out of ideas. I might just get rid of the halt signal entirely and just use a jump instruction that points to itself when I want to stop the program.
This is the first "program" that I've successfully run on my 8-bit CPU. It loads 69 into the A register, and then halts (can't program anything else since those are the only two instructions I've programmed the microcode for).
I cannot describe how good this feels. When I was around 8 years old, I asked my dad (a software developer) a question: "How do computers know how to run the code?" He didn't know the answer since he's mostly a software guy. I'm now 17, and I finally feel like I understand the answer to my question.
On the NES and SNES, the reset button would send a reset signal to all of the hardware in the console, and cause it to behave as if it was just powered on. If a cartridge doesn't make a good connection, you could just wiggle it and then press the reset button. On the n64, this doesn't work. You need to use the power switch to restart it if the game doesn't work on the first try. Why doesn't the reset button do the same thing as older systems in this situation? Is it not actually wired directly to the CPU reset signal?
Instead of using Ben eater's design for the memory, I am upgrading things quite a bit. I have two 8-bit address registers for a total address width of 16 bits. I'm planning to split it in half. The lower half will be allocated for ROM (a 28c64 EEPROM), and the upper half will be RAM (Hitachi 62256). The I/O pins on both chips will be connected directly to the bus.
I believe this design should work, but I want to get your input first. Also, I am aware that the EEPROM I am using is smaller than the address space I have allocated for it.
Last year, I started building the 8-bit CPU. But the specs of Ben eater's design weren't great (how am I supposed to do anything with 16 bytes of memory?), so I decided to make some changes. Around May, I decided to take a break from it. While I was moving it to a different place, I accidentally dropped it and a bunch of stuff got displaced, and that made me want to push off resuming the project even further. Today, I decided that I wanted to start working on it again, but I can't; I don't know how most of my design modifications work anymore. I don't even remember what one of the custom modules I built was even for anymore.
I'm just about ready to start over, but this time I won't put off documenting the changes I make to the original design. For those who made their own designs and said "I'll draw a schematic later, I know how it works", don't wait. Make a diagram now, before you forget how it works!
I've heard people say that 2V is the absolute minimum for the SRAM chips in game cartridges, but my copy of Mario Land 2 somehow still has a save file, despite the battery being below 1V!
Just got this console and 2 controllers delivered today, so I decided to fully disassemble them and clean them. It's not perfect, but it's so much better. I've only cleaned one of the controllers so far, but now I can play some games without touching 20+ year old dried up dirt and sweat.
I'm going to lose my mind. I've replaced the laser assembly, lubricated all the rails, and I've also tried different games. I've also double checked that the anti static solder blob is completely gone. When I put in an Xbox 360 game, the drive tries to read it, and then makes a weird rapid clicking noise before giving up. I'm pretty sure the new laser is fine, because it reads CDs and DVDs just fine. It's just games that don't work. I might just sell this console for parts, I'm so upset
I recently picked up this untested console, but I think need to clean the cartridge slot. I'm pretty sure the PPU is fine, because the audio is also messed up. Depending on how much I wiggle the game in the slot, different songs and sound effects from the game play.
I was getting ready to sell this one after replacing the battery, and another problem appeared. The hold switch works properly, but it also locks whenever pressure is applied to the top left corner. What could be causing this?
The RV park I went to had a frogger machine, but I can't play it because I don't have any quarters. The place is completely cashless so I couldn't just ask the cashier at the front desk to give me some quarters for a dollar bill
I have an iPod classic 4th gen monochrome iPod, and it's making me go insane. I am on my 3rd replacement battery, and I keep having the same problem every single time. Here's what keeps happening:
The iPod acts as if the hard drive is dead instead of booting (image 1). Sometimes it shows that icon instantly, other times I can hear the hard drive trying to spin up and stopping repeatedly for a few seconds before it shows on screen. When I plug it into FireWire, it immediately opens the diagnostic menu, where I checked the smart data and ran a full HDD scan multiple times. I am fairly confident that the hard drive is not the issue. Plugging it into my computer over USB just shows a charging battery icon (image 2) and occasionally tries to spin up the HDD for a few seconds before it dies and tries booting again.
I replace the battery, and it boots instantly as if nothing ever happened. It won't charge over USB, but that's fine; I have a FireWire charger. I fully charge it with FireWire.
It works for a few days, and then dies again. I plug it into FireWire, and it automatically opens the diagnostic menu again. I leave it to charge over FireWire overnight. In the morning, I unplug it from FireWire and try booting it. It immediately shows the sad iPod icon again and I'm back to step 1.
This is driving me insane, and it's happened 3 times with 3 different replacement batteries in the past few weeks. I've tried buying from elite obsolete. I tried different brands on Amazon. Ice tried a random eBay seller. All of the batteries I've tried are doing this to me. I've also made sure that the batteries physically look different to ensure that I'm not getting all of them from the same faulty batch or something.
Does anyone have a solution? I'm close to just selling it for parts and giving up.
A few days ago, my Toshiba 27af44 started making a high pitched noise. It only seems to happen when the picture contains lots of light colors. I posted about it a couple days ago, but I didn't get many helpful comments. Before you say that it's normal, this is NOT the usual 15kHz tone from the flyback transformer. I used an app on my phone to analyze the audio, and there are two different tones around 8kHz that are not present when the TV is displaying nothing. What can I do to fix this? The 15kHz ringing is fine, but this new ringing noise is very distracting and prevents me from using the TV.
My Toshiba 27af44 just started making this very loud whining noise today. It's not the normal whine from the flyback transformer. It is similar, but it's extremely loud. I've had the TV for a few weeks and it's never done this before. Any thoughts?
I recently picked up a Sony SLV-N70 from a thrift store, but I don't think it's rewinding properly. When I press fast forward, it starts slowly. After a few seconds, the tape stops and switches to a much faster speed. But for rewinding, it never switches to the faster speed. Does anyone know what the problem might be?
I'm trying to sell a motherboard for an old iPod, but I can't list it. Instead, I keep getting this error. If you ignore all the unparsed HTML in the message, it seems to think that I'm listing it with an accessory, but I'm not. What can I do about this?
I bought a few broken iPods to fix, and I've been checking all the hard drives. This one says it has 180 hours, but only 48 starts and stops. Since the hard drive usually only spins up for a few seconds every few songs, how is this possible? Is it not reporting the data correctly?
I have a bunch of music I purchased on iTunes. I noticed that my iPod was skipping certain songs at the same part every time I played them. I passed it off as an aging hard drive issue, but that wasn't the problem. Today, I used the same computer that I use my iPod with to sync with my old iPhone 5s. When playing the songs on the iPhone, the same thing happens. Is this a problem with the files I downloaded from iTunes on my computer? Does anyone know what might be the problem?