What To Know When Buying Chips That Haven’t Been Made For Three Decades

Those of us who have worked with vintage sound generator chips such as the Yamaha FM synthesizers in recent years have likely run into our own fair share of “fake” or “remarked” chips, sometimes relabeled to appear as a chip different than the die inside the packaging entirely. [David Viens] from Plogue has finally released his findings on the matter after 3 years of research. (Video, embedded below.)

The first thing to determine is in what way are these chips “fake”? Clearly no new YM2612’s were manufactured by Yamaha in 2015, but that doesn’t mean that these are simply unlicensed clones put out by another die factory. [David] explains how these chips are often original specimens sourced from recycled electronic waste from mostly environmentally unsafe operations in China, which are then reconditioned and remarked to be passed as “new” by resellers. Thankfully, as of 2017, he explains that most of these operations are now being shut down and moved into an industrial park where the work can be done in a less polluting manner.

The next thing that [David] dives into is how these remarked chips can be spotted. He explains how to use telltale signs in the IC packaging to identify which chip plant produced them, and visible indications of a chip that has been de-soldered from a board and reconditioned. There are different ways in which the remarking can be done, and sometimes it’s possible to undo the black-top, as it’s called, and reveal the original markings underneath with the simple application of acetone with a cotton swab.

We’ve talked about fake chips and how they can lead to hardware failure here before, but in the case of chips like these which aren’t manufactured anymore, we’re not left with much choice other than FPGA or software reimplementations. Check out [David]’s 40-minute look into these chips after the break.

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Repairdown: Disklavier DKC500RW Control Unit

If you’ve been kind enough to accompany me on these regular hardware explorations, you’ve likely recognized a trend with regards to the gadgets that go under the knife. Generally speaking, the devices I take apart for your viewing pleasure come to us from the clearance rack of a big box retailer, the thrift store, or the always generous “AS-IS” section on eBay. There’s something of a cost-benefit analysis performed each time I pick up a piece of gear for dissection, and it probably won’t surprise you to find that the least expensive doggy in the window is usually the one that secures its fifteen minutes of Internet fame.

DKC500RW installed on right side.

But this month I present to you, Good Reader, something a bit different. This time I’m not taking something apart just for the simple joy of seeing PCB laid bare. I’ve been given the task of repairing an expensive piece of antiquated oddball equipment because, quite frankly, nobody else wanted to do it. If we happen to find ourselves learning about its inner workings in the process, that’s just the cost of doing business with a Hackaday writer.

The situation as explained to me is that in the late 1990’s, my brother’s employer purchased a Yamaha Mark II XG “Baby Grand” piano for somewhere in the neighborhood of $20,000. This particular model was selected for its ability to play MIDI files from 3.5 inch floppy disks, complete with the rather ghostly effect of the keys moving by themselves. The idea was that you could set this piano up in your lobby with a floppy full of Barry Manilow’s greatest hits, and your establishment would instantly be dripping with automated class.

Unfortunately, about a month or so back, the piano’s Disklavier DKC500RW control unit stopped reading disks. The piano itself still worked, but now required a human to do the playing. Calls were made, but as you might expect, most repair centers politely declined around the time they heard the word “floppy” and anyone who stayed on the line quoted a price that simply wasn’t economical.

Before they resorted to hiring a pianist, perhaps a rare example of a human taking a robot’s job, my brother asked if he could remove the control unit and see if I could make any sense of it. So with that, let’s dig into this vintage piece of musical equipment and see what a five figure price tag got you at the turn of the millennium.

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MIDI Synthesizer From A Sega Genesis

[Aidan] is really into FM synthesis chips for creating audio, and one of the most interesting chips from that era is found on the Sega Genesis. Anyone involved in the console wars at that time certainly remembers the classic, unique sound that those video game systems were able to produce, so [Aidan] built a device using a sound chip from a Genesis to play any piece of music from any game. The second iteration of that project, though, is able to use those same sound files as a MIDI synthesizer.

The interesting aspect of these chips is how they use registers to change the audio output. Essentially, there is a complicated register map (one section of his write-up is simply called “Register Hell”) that can be called in order to access the various types of effects one would normally see on a synthesizer. It’s not straightforward at all, though, and got even more complicated once [Aidan] started adding MIDI functionality to it as well. Once he finished sifting through the Sega Genesis technical manuals and a bunch of registers, though, he had a unique synthesizer working that doesn’t sound like anything you’ve ever heard, unless you’ve ever played a Genesis.

If you’d like to check out his first project, the MegaBlaster, which plays the sound files of the old Genesis games directly, we featured that a while ago. Keep in mind though that his latest project isn’t just an updated MegaBlaster, though. He built this entire thing from the ground up.

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Raspberry Pi Radio Streaming Service Guts Yamaha Shelf System

There are dozens — dozens! — of options to meet your music and streaming needs these days.  Looking to make something of his own that retains that 90’s vibe of having a dedicated stereo system but with modern wireless integration, [thk4711] turned an old Yamaha hifi into a Raspberry Pi streaming client.

As far as the case goes, a few modifications allowed [thk4711] to use all of the existing buttons, and a quick-swap of the back-plate and screen gave him a better enclosure than one he could fabricate himself. The power supply proved to be the most difficult part of the project due in part to some “digital noise” interference between the digital and analog components while they were wired to a common ground. This was solved by implementing two transformers, a LM2596 voltage regulator and a LT1084 low-noise power supply to smooth things out.

The Raspberry Pi 2-centered device supports internet radio, Spotify connect, Airplay, USB and auxiliary inputs.

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Zynq And The OPL3 Music Synthesizer

We’re big fans of the Zynq, which is an answer to the question: what do you get when you cross a big ARM processor with a big FPGA? So it isn’t surprising that [GregTaylor’s] project to emulate the OPL3 FM Synthesis chip in an FPGA using the Zynq caught our eye.

The OPL3 (also known as the Yamaha YMF262) was a very common MIDI chip on older PC sound cards. If you had a Sound Blaster Pro or 16 board, you had an OPL3 chip in your PC. The OPL3 was responsible for a lot of the music you associate with vintage video games like Doom. [Greg] not only duplicated the chip’s functions, but also ported imfplay from DOS to run on the Zynq’s ARM processors so he could reproduce those old video game sounds.

The Zybo board that [Greg] uses includes an Analog Devices SSM2603 audio codec with dual 24-bit DACs and 256X oversampling. However, the interface to the codec is isolated in the code, so it ought to be possible to port the design to other hardware without much trouble.

To better match the original device’s sampling rate with the faster CODEC, this design runs at a slightly slower frequency than the OPL3, but thanks to the efficient FPGA logic, the new device can easily keep up with the 49.7 kHz sample rate.

Using an FPGA to emulate an OPL3 might seem to be overkill, but we’ve seen worse. If you prefer to do your synthesis old school, you can probably get a bulk price on 555 chips.

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Forkless Motorcycle Tears Up The Track

The bike above may look like a pristine Yamaha prototype, but it’s actually the work of [Julian Farnam], a motorcycle hacker of the highest level. We caught his Yamaha A-N-D FFE 350 on OddBike, and you can read [Julian’s] own description of the bike on his Slideshare link.

The FFE 350 started life as a Yamaha 1990’s RZ350 two-stroke racer. From there, [Julian] gave it his own Forkless Front End (FFE) treatment. Gone is the front fork, which while common in motorcycle and bicycle design, has some problems. Fore-aft flex is one – two thin tubes will never make for a rigid front end. Changing geometry is another issue. Since forks are angled forward, the front wheel moves up and to the rear as the shocks compress. This changes the motorcycle’s trail, as well.

Forkless designs may not have these issues, but they bring in a set of their own. A forkless design must have linkages and bellcranks which are often the source of slop and vibration. [Julian’s] design uses two sets of linkages in tension. The tension between the two linkages removes most of the slop and provides that directly connected feel riders associate with forks.

The FFE 350 wasn’t just a garage queen either – it laid down some serious laps at local tracks in Southern California. Unfortunately, the forkless design was too radical to catch on as a commercial venture, and the FFE has spent the last few years in storage. [Julian] is hard at work bringing it back to its 1998 glory, as can be seen on his restoration thread over on the Custom Fighters forum.

Put That Headphone Jack Anywhere You Want It

yamaha-keyboard-headphone-jack-hack

Check out this brand new Yamaha keyboard. The fact that we’re seeing the guts means that [Todd Harrison] can kiss his warranty goodbye. But by now you should know that he doesn’t look to others when something goes wrong with his electronics. This time around he’s not repairing anything. He didn’t like having to plug in headphones on the rear of the keyboard. He cracked it open and relocated the headphone jack to a more convenient location.

As you can see, there’s a ton of room inside once the MDF base which holds the speakers and some sounding boxes has been removed. While he’s in there he takes a good look at the mechanics of the keys. They’re weighted with metal rods (seen above) to help the electronic instrument feel more like an acoustic version to the player. But he doesn’t neglect the chance to gawk at all the electronics as well.

After pulling out the PCB that has the headphone jack on it he goes to work with a solder sucker. With the solder gone he cuts through the glue that holds the jack on the board. All that’s left is to solder some wire in its place and give it a nice project box as an enclosure. To complete the hack he mounts the box on the MDF base and now the headphones connect on the front. See the entire process in the video after the break.

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