Back to the Electronic Home Keyboards page
The Casio PT-50 was one of the first keyboards to have the ROM Pack
system, the other being the MT-800. Unlike the later ROM Pack
keyboards, there are no LEDs above the keys. Instead, the LCD display
shows a diagram of the keyboard with small blobs that indicate the key
to be played, while the alphanumeric section of the display shows the
The PT-50 also seems to be the only keyboard that supported the
writable "RAM Pack" cartridges, which could be used to save data from
the keyboard's internal sequencer. The sequencer can either be
programmed in real-time, or by using the "One-Key" method,
whereby notes and chords and their respective durations are
programmed independently. Even in real-time mode, melody and chord
sequences must be programmed separately - it is apparently not
possible to record and replay a complete performance in real-time.
Correction of stored data is possible, but rather fiddly. There is no
way to program the "obligato" track, even though this is used when ROM
Pack music is loaded into the sequencer memory (see below).
Manual play is monophonic. There are 8 voices, which sound quite dull
and almost muffled, like a bad tape recording. The 16 rhythms consist
of noise pulses, but without the usual metallic timbre often heard on
these early keyboards. The auto accopaniment patterns sound quite nice,
with fairly rich bass. The internal speaker delivers a fair amount of
bass, but unfortunately resonates quite badly at the upper end of the
keyboard range, particularly when using the "Flute" voice which is an
octave higher than the other voices. There's also a Transposer
Unlike other ROM Pack keyboards, the PT-50 does not play the programmed
music directly from the ROM. Instead, the music is first copied into
the PT-50's internal sequencer memory and then played from there, thus
overwriting anything already stored. The
ROM Pack can then be removed from the keyboard, and provided batteries
are installed, the music is retained in memory indefinitely, even if
the keyboard is switched off.
Interestingly, there is a compartment in the underside of the keyboard
to accept a "TA-1" cassette tape interface, which can be used to save
and load sequencer data to/from audio cassette tapes, much like the
1980s home computers. I do not own a TA-1 so I'm not sure exactly what
is possible with this device, but any attempt to use the cassette
interface without it being present causes the keyboard to freeze up for
a long time, and switching off and on again does not recover the
situation - you just have to wait.
This is a very nice, warm-sounding keyboard, which renders ROM Pack
music very nicely.
More PT-50 audio samples on the RO-201
The original manual was bilingual, with English and Spanish sections.
Only the English pages are included.