Rhodes MK-80
Eighty-eight weighted keys, a backlit two-line display, and a service manual that says the ROM was stamped July 3, 1989. This is the digital Rhodes that most players have never touched.
Overview
The MK-80 is a Rhodes-badged digital piano built on Roland hardware, and the service documentation gives it away. The main board carries a Roland part number, the stand is the RS-80, and the test-mode ROM version reads "Ver 1.01 July 3 1989." Whatever the badge says, the guts are a late-Eighties Japanese digital piano with a Rhodes nameplate on the front panel. Collectors have argued about that for years. The documentation doesn't leave much to argue with.
The keyboard is the headline. Eighty-eight keys, A to C, with piano touch — a full weighted action rather than the synth-action compromise that showed up on a lot of digital pianos of the period.
The sound engine is built around 64 memory types of voices, including CLASSIC, SPEC A.PIANO 2, VIE CONTEMPORAL BRAPHONE D, and A.PIANO 1, plus 8 preset tones and 56 tunable tones. Contemporary reviewers noted that alongside four extraordinary sounds - concert grand piano, electric grand piano, clav, and vibraphone - the instrument offered a broad palette of variations (Mix, January 1990, p.23). The editing goes deeper than the front panel suggests. There's a full EQ-Mid section on the effect board with adjustable frequency, boost, and cut, calibrated against test point TP3 with a scope at 0.1 V/div. It is not a preset-only instrument, and anyone willing to work the cursor buttons can shape the sound a good deal.
The display is a 16-character, two-line backlit LCD. It's small, but it's enough to get around the tuning, MIDI, and edit functions. Output level is specified at -0.8 dBm with the power-on basic settings and the slider at a given position. The output is line-level. The pedal input runs on control voltage: 0 V (00) to 5 V (7F), ON at 5 V, OFF at 0 V. That makes it a continuous pedal, not a simple switch, so keep that in mind before buying a replacement.
Power consumption is listed at 27 W on 100 V and 117 V, and 30 W on 220 V and 240 V. The unit measures 1370 × 546 × 152 mm and weighs 34.5 kg / 76 lb 3 oz. That's heavy, and the RS-80 stand is close to mandatory. It has three height settings at 660, 730, and 800 mm and five width positions. For the MK-80, the stand's width measurement F should be set to 262 mm. The narrower MK-60 setting of 2 mm is not correct for this model, and used examples often get it wrong.
The service manual is unusually generous for the era. It documents a full test mode, entered either from the panel with a specific cursor-and-variation-button sequence or by flipping MAIN-A board SW1 to TEST before power-up. It also covers factory preset restoration via a "Cold Boot?" routine, bulk data dump and load over MIDI for saving user variations before servicing, and a troubleshooting logic tree. The effect board has documented revision breaks: certain capacitor and resistor values apply only to PCB assembly 76227300 (PCB 22925758 00) or units with serial numbers up to ZA40300. Check the serial before ordering parts.
The parts list is just as thorough. The main boards use 2SC-1740S and 2SA-933S transistors. The effect board carries 2SC1815GR, 2SA1015GR, 2SB-605L, 2SD-571L, and 2SK363GR FETs. The crystals are HC-49/U types at 16 MHz on Main A and 12.8 MHz on Main B. Resistor arrays are documented by value and board. That level of detail is why MK-80s are still repairable while plenty of their contemporaries are not.
The one gap worth flagging: the manual's own accessory list names an owner's manual, warranty information, and a pedal unit, but the instrument's production years and original retail price are not documented in the material available here. What is clear is that the MK-80 sits in an awkward spot historically — a Rhodes in name, a Roland in construction, and a digital piano at the moment the category was being redefined. That ambiguity is exactly why it's interesting.
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