|It would be a hell job to search for matrix eastereggs inside this nasty hardware design.|
|On the PCB there are some empty holes where an additional logic IC was planned.|
|At least with my specimen of PT-30 the speaker has a very unpleasant, loud mid- range resonance and some keys squeaked badly when pressed (I lubed them with thick silicone oil to fix them). The hardware of this instrument consists of 2 stacked, large PCBs with much analogue stuff. Unfortunately the SMD CPU sits at the rear side of the control panel PCB, which makes this instrument extremely awkward to analyse because the buttons and silicone contacts tend to fall out and the LCD with its fragile plastic foil cable can easily break or get dusty inside during measurement attempts at the CPU. (I didn't dare to analyse it further yet, but at least made some PCB photos.) The CPU is of the same "D1868G" series like in Casio PT-80, but the following 3 digits are different and it communicates with an additional small IC "HD B 61914". First I though the small IC would be an external program ROM and the CPU would be the same. But because my PT-50 contains also a D1868G series CPU and 2 identical "HD B 61914" ICs, and the latter are also used in the RAM-Pack RA-1, I conclude that the 61914 ICs are SRAMs for the sequencer, and the numbers "001" and "007" at the end of the CPU type "D1868G" instead indicate that both CPUs contain different software in their internal ROM.|
The analogue rhythms have an interesting timbre with partly long sustaining white noise "cymbals". The toms seem to be based on squarewave tones produced by the main CPU and muffled by external capacitors. But at least my PT-30 specimen has not the strange popping base drum of the technically similar PT-80. The manual organ chord mode plays a sort of thin metal pipe organ rank timbre layered with a warm and dull organ bass and a small dose of sustain. The accompaniment with rhythm simulates a kind of piano and e-bass sound using these waveforms with decay envelope. The 2 "chord change" buttons almost immediately restart the current rhythm pattern on each a different step, which can be used as a sound effect.
The sequencer works quite similar like with Casio VL-Tone 1. To record or edit anything in the sequencer contents, switch the power switch to "record". You can now simply play keyboard (including chords) and everything is recorded. Press "memory play" to listen to it. To change the note lengths, play the melody with the "one key play" buttons in the correct tempo. To delete the last heard note or chord press "del.". Use the arrow buttons "<", ">" to step back and forward (notes and chords sound alternatingly to ease deleting). Any now played notes or chords are inserted at the current position. With the "chord change" buttons you can step the value of a currently displayed chord up and down. To delete the entire song, press "clear". The sequencer supports 8 songs; to switch between songs, press "memory" followed by one of the black keys "M1".."M8". I have no manual for my PT-30, thus there may be still hidden features I don't know. E.g. you can select "edit" here, which in "play" mode simply behaves like an empty memory and in "record" mode mutes the keyboard. The arrow buttons are labelled "save" and "load", which likely refers to the optional TA-1 expansion module to save sequencer data on audio cassettes. Likely you have to set the power switch to "MT", select a song memory and press "save" or "load" to save or load data from cassette.
|Casio TA-1 (tape storage cartridge for sequencer data)I now finally got the occasion to buy the very rare Casio TA-1 cartridge ("Tape recorder interface for CASIO electronic keyboard"), originally packaged with manual and connection cable.|
I don't know if "Kansas City standards" is anything documented or just a fancy name for a proprietary data format. I also yet haven't tested to save and load data with it. By my knowledge only the Casio PT-30 and PT-50 have a cartridge slot for the TA-1, but possibly also others exist; in the TA-1 manual there is no list of compatible keyboard types included.
An interesting fact is that Casio first advertised this tape saving feature as "MT" (for "magnetic tape") and later(?) named their entire midsize keyboards series "MT-..." despite none of them included a tape interface. Later Casio named a midsize toy keyboard with built-in stereo cassette player Casio TA-10, which also has no sequencer functions.
A likely direct successor of the PT-30 was the Casio PT-50, which case layout looks almost identical but has a ROM-Pack music cartridge slot (without key lighting) in the upper right corner and the strange case groove is gone. It could not only save sequencer data on cassettes (using the optional TA-1), but even on very obscure RAM- Pack cartridges those look like ROM-Packs but are certainly as rare as the TA-1. In detail there are many small differences between PT-30 and PT-50; e.g. some sounds and especially the entire rhythm set is different.
Also the rare ghettoblaster Fisher SC-300 Stereo Composer likely contained on its top a detachable Casio PT-30 (with different case style resembling Casio PT-50).