NES multi-cartridge

Here’s a mutlicartridge hack for the original NES that [Callan Brown] put together. He spent some time snooping around the signals on the circuit board seen above until he found the trace that maps the reset signal from the game console. This will be used to cycle through the various games stored on the cart’s memory chip. The ROM images that will be stored on this cartridge are concatenated, then burned to the EPROM. Since the donor cartridge (and the ROMs which were chosen) use memory managment, the hardware can be tricked into reading the ROM from a specific point in the EPROM.

The switching itself is handled by a 74HC161 binary counter chip. The reset signal from the on-board security chip acts as a clock trigger for the counter. Some clever wiring allows the output of the counter to select the starting address for the EPROM. Each time you press the reset button it increments the counter, thereby selecting a different ROM to load. See [Callan] demonstrate the finished hack in the video after the break.

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Xerox Phaser drum unit hacked, lives to print another day

Faced with a printer that would stop printing for no apparent reason, Finnish pirate and hacker [Janne] decided he had had enough. After doing a bit of research, he disassembled the drum assembly and replaced some components. The end result? Supposedly ‘broken’ printers started working again.

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Creating NES cartridge clones from ROM dumps


Sometimes emulators just don’t cut it when you want to play a vintage game. Like it or not, some people enjoy the nostalgia of playing old games on the actual hardware for which it was designed.

[Callan] wrote in to share a method he has been using to make some of his own NES game cartridges from ROM dumps in order to play them on an honest to goodness NES console.

He starts out with a 190 in 1 game cartridge, where he found a neat Famicom game never released in the US. He decided he would patch the ROM he found on the multicart in order to have an English menu, and then create his very own cartridge from the image. He discusses how to identify which EPROM chips you will need in order to construct your cartridge, as well as some helpful ways of finding a donor cart that has a similar enough board to house your components.

[Callan] also provides a quick walkthrough of erasing and burning your new EPROM chips, before discussing some post-soldering troubleshooting steps you might need to take before your game will work properly.

While we can’t comment on the legality of these game clones, we still think it’s pretty awesome.

Be sure to check out his site for a far more in-depth discussion of the process if this is something that interests you.

Old school LED light show


Building LED arrays that can display all sorts of different patterns is pretty easy these days. Hook up an Arduino, do some charlieplexing, and off you go. When [Viktor] was younger he didn’t have all those fancy schmancy microcontrollers and circuit simulation software you kids have these days. In fact, last we heard, he had to walk to school uphill both ways – in the snow.

That didn’t stop him from building this gem of a project back in 1987. His LED chaser/light show does not use any microcontrollers at all, rather it relies on an EPROM to store predefined display programs. A series of switches are installed on the front of the flasher, allowing him to easily switch between the programs, and a pot is mounted to the front of the device to control the speed of the LEDs.

His light show is pretty slick, even for a project built over 20 years ago. Sometimes you just can’t beat a good, old-school hack.

Continue reading for a video demonstration of [Viktor's] programmable light show.

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Animating an LED matrix without a microcontroller

[Konstantin] had some extra 27C256 EPROMS lying around and decided to use them to animate an 8×8 LED matrix. He’s not only using them to store data, but driving the display with them as well. The chip holds 32 kilobytes of data which equates to 4096 frames of animation. A 32 kHz clock circuit works with some ripple counters to scroll through each byte of stored data, turning on the columns while sinking the proper row. Of course current protection is a must so there is a ULN2308A darlington driver and some 2N2907 transistors at work, but you won’t find a programmable microcontroller. Neat!

Yep, you read that right. The picture above shows an EPROM chip that requires a UV light source to erase the data.

[Thanks Kopfkopfkopfaffe]

UV EPROM eraser in a toolbox

[Devon Croy] belongs to a hackerspace that works hard to keep hardware from going to the landfill. He found they were in possession of over a hundred Erasable Programmable Read Only Memory chips (EPROM). Not to be confused with EEPROM, which are electronically erasable, these EPROM chips require a strong source of UV light to blank the old data before they can be written again.

Instead of buying a tool to erase two or three chips at a time he built his own bulk EPROM eraser from an old metal toolbox. He used parts from a fluorescent black light and acquired a new bulb that generates light in the UVC spectrum, the band which works as an eraser for the chips. After bolting the parts into the case he added a spring-loaded timer knob and a safety switch that kills the power when the case is opened, similar to the UV exposure box we looked at yesterday.

Of course, if you don’t need a bulk eraser you could shop some garage sales for a UV pacifier cleaner which can also erase EPROM chips.

Don’t put that EPROM in your mouth!

[Jeremy] had some chips on hand that included EPROM.  We’re not talking about EEPROM, we mean EPROM that need a UV light source to erase. Most people don’t want to drop a few hundred dollars on a dedicated EPROM eraser, there must be another way.

Boy, EPROM really suck. But so do pacifiers and he already had a solution for exposing those to UV. He pulled out his $30 UV pacifier cleaner and tossed the chip inside. Two times through the cleaning cycle and the data was gone. We’ve looked into using UV LEDs to do the job but some experimentation shows that it doesn’t work. These pacifier cleaners are cheap and easy to get a hold of. The real question is are you still using chips that require UV for erasing?


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