The Yamaha PSR-E413 is a digital keyboard introduced in May 2008—one of the relatively "low-end" models available from Yamaha between then and January 2010, when it was replaced by the PSR-E423. Like many modern digital keyboards, it has a remarkable variety of features and sound possibilities, and all for a relatively low cost; I believe I paid around $250 CAD for it new. Of course, compromises have been made in order to achieve such low cost, to be discussed further below.
Because this is a relatively recent model that has a great deal of online information already, the focus here will be mainly on its internal hardware and build quality (which I haven't seen discussed anywhere else), rather than its features / software capabilities.
Before criticizing this keyboard, I will first mention what it does well. Mainly, like many modern digital keyboards, the software is really quite impressive. For one, it is capable of generating a total of 509 different voices, most of them emulations of other instruments. My personal favorite feature is the automatic accompaniment / "music database", of which there are 300 styles to choose from. The pitch-bend wheel is also magnificent. If you've listened to almost any S.F.A.T.B.H.S. album, you know what a fantastic instrument this is in terms of its ridiculous sounds. As well, honestly, for such an inexpensive keyboard, the "feel" of the keys and the other controls is perfectly fine. Basically, it's quite a fun instrument to play around with, and it is extremely versatile. Now...
Despite the versatility of this instrument, the hardware is unfortunately quite disappointing as compared to my vintage instruments. Being made in 2008 (well past the era of relatively high manufacturing and design quality of consumer electronics), and also being a relatively low-end instrument, this keyboard is made with cheap materials and designed without much apparent concern as to serviceability. Not surprisingly, it is made in China, rather than Hamamatsu, Japan, where Yamaha manufactured higher quality electronic keyboards in the past (such at the CP-30 and C-55I units that are also at JCS).
The instrument's body is made almost entirely of plastic, and is held together by many screws that are screwed directly into plastic posts. Taking a good few screws out allows for the main bottom piece to come off, which covers most of the components except for the keybed. Right away, and not surprisingly for those who are familiar with modern electronics, it is clear that the keyboard is essentially a purpose-built microcontroller-based computer. Most of the electronics are on a small double-sided PCB populated with nearly all surface-mount components. The cables are encased in thin foam sleeves for some reason, and are secured to the plastic body either in a groove by friction alone or with low-quality adhesive tape, which has already detached itself in many places.
Let's take a closer look at that main board. A few chips can be nicely spotted. For example, the Yamaha X935410, which I think is probably a ROM chip. Looking online, there are extremely few references to the chip, no datasheet, and the only sellers are some sketchy-looking Alibaba vendors with widely varying prices (from around $5.00 ea. to around $30.00 USD each). They're all using the exact same image, many list the brand name as "Good quality", as well as listing it as a "voltage regulator". (Gee, what a lot of voltages it could regulate with so many pins, and with great power dissipation! *cough*) Another chip is the MX 29LV400CBTC-70G, which is a 512 KB flash EEPROM. As of 12/11/2015, I was able to find a single supplier for this chip on Alibaba. However, considering it's an EEPROM, it may have to be programmed properly in order to be usable. Of course, Yamaha hasn't even released a service manual for this instrument, let alone software for an EEPROM!
Another chip is the Yamaha YMW767-VT "CPU & XG Lite Generator", which is responsible for sound generation and possibly other main functions. As described on the "Edward d-tech" website's list of Yamaha synthesizer chips, it is a "CPU with minimalistic hardware SWP-xx type synth. No insert/aux effect, only reverb&chorus; 32-voices." I found a few suppliers of this chip on Alibaba, but again all using the exact same stock image (which shows a counterfeit-looking chip—very low quality printing on it), and listing it as another "voltage regulator"! There is nothing to suggest these vendors have any real understanding of what they have, or whether or not they actually have it at all. The pictures alone may suggest that the chips are counterfeit too, which is a common problem with these Chinese vendors.
How about the M38K07M4LHP? Based on a datasheet from Renesas for the M38K07M4-XXXFP, it is an 8-bit microcontroller. After the "M38K07", the "M" indicates that it has a mask ROM (i.e. hard-coded in the die), "4" indicates 16384 bytes of ROM, "L" indicates the ROM variant (which is very important!), and "HP" indicates the package type. I could not find any supplier for this chip.
You may notice that a pattern has emerged here. Most of the important chips on this board are either only available from possibly disreputable Chinese vendors with no clue what they are, or not available from anywhere. Of course, even if there were reliable sources for these components, with complex surface-mount digital chips like these, it can be terribly difficult to even diagnose a fault, let alone perform a chip replacement. The usual situation is that the entire board would have to be replaced, but of course, I could not find a replacement for the board assembly anywhere online. It's very unlikely that even Yamaha would have a spare, considering this keyboard has been superceded three (soon to be four) times already; more on that later. This summarizes the unfortunate situation that exists in these digital keyboards, as well as most consumer electronics made today. They are not designed to be long-lasting, nor to be serviced. They are designed to break and be disposed of, and there are any number of equally cheap and short-lived devices waiting to take their place.
I would say that a large shift occurred around the early to mid 80s with respect to electronics. Devices made prior to this time were typically designed with relatively more serviceability in mind, or at the very least with components (like discrete transistors, simple ICs such as op-amps and TTL logic, etc.) that continue to be common and easy-to-replace to this day. Such vintage electronics also tend to have PCBs with all through-hole components, rather than the modern standard of having nearly all surface-mount components. Some devices, especially those using vacuum tubes, don't even use PCBs at all, having instead point-to-point wiring, which is often the absolute best in terms of ease of repair. Longer-lasting, more robust structural and casing materials (such as metal and wood) were also more common prior to the mid-80s. I have some keyboards (for example, the Юность) that have been so abused that if they had been made of this kind of plastic, the casings would have been shattered decades ago.
Another thing to note is that this keyboard is a perfect example of a device made with "planned obsolescence" in mind; allow me to explain. This keyboard was introduced in May 2008, with my unit being made in July 2008 at the earliest, based on the date molded in the plastic casing:
As of this writing, that's only a little over seven years ago. In that short time, the production of the keyboard has been discontinued, being replaced by the PSR-E423 in January 2010. The PSR-E423 has also been discontinued, being replaced by the PSR-E433 in 2012. The PSR-E433 has also been discontinued, being replaced by the PSR-E443 in 2014. Although, as of December 8th, 2015, the PSR-E443 has not yet been discontinued, the PSR-E453 is already slated for release in 2016, so it is only a matter of time. It seems the PSR-E4x3 models are being discontinued and superceded every even-numbered year. I hope I am not the only one who thinks that having a planned two-year replacement cycle for a musical instrument is absolutely ridiculous.
The last thing that I'd like to mention is one particular design aspect that may be another example of planned obsolescence. Those who repair electronics know that electrolytic capacitors are one of the most failure-prone types of component. As well, they are sensitive to heat, with the lifespan of the capacitor decreasing with exposure to high temperatures. How interesting, then, that Yamaha decided to put so many of the electrolytic capacitors right next to the body and heatsink of the BA5417 stereo power amplifier chip! Also the BA60BC0, which is actually a voltage regulator. This is especially interesting considering that the board has a huge amount of ununused area that the capacitors could otherwise have been placed in. Of course, it's basically impossible to say for sure if this was done with planned obsolescence in mind, but it certainly could have been. As it turns out, placing electrolytic capacitors near hot components is actually a common tactic to reduce the lifespan of a device; so well known, in fact, that it's listed in the planned obsolescence Wikipedia article. Luckily though, electrolytic capacitors are some of the simplest devices to replace should they go bad.
To some extent, I wish that there was a real "high end" equivalent to this kind of keyboard; something with the serviceability and longevity of a vintage instrument, but with the unbelievable versatility of this kind of modern digital unit. There are indeed some very expensive keyboards on the market today, like Yamaha's Tyros series, but their serviceability and overall materials quality isn't much better; most of the money is going towards the fancy software, big LCD, and more/nicer keys/controls. Even the Tyros 5, which sells for about $5,500 USD at the moment, has a body made almost entirely of plastic! Anyway, I'm worried that an instrument like this will be impossible to find in working order in the not-too-distant future. It may become a sort of "dead instrument" that, unlike the acoustic "dead instruments" of the past, would be too complex to recreate. Already, it has become somewhat difficult to find some of the inexpensive digital keyboards of the 90s in working order. My only example of this, the Casio SA-35, has become defective, and I think it's a problem with the "unobtainium" microcontroller chip.
All in all, the PSR-E413 a versatile instrument that has been truly fundamental to many "classic" JCS recordings, including every single S.F.A.T.B.H.S. album except for Лананыкс, and both Jesse Acorn's Demos, or perhaps not... and Ридахций. It even carries the distinction of being the leg-endary "Turk Dammit Signature Keybode"! Unfortunately, it may be destined to a relatively early death. Nonetheless, I will try to keep it alive as long as possible!