Build Of Materials
Yamaha PSS-140 = $0.00 /Free,
Donation from a friend. Thanks Rob Walker – Leave no Veteran Behind!
LTC1799 oscillator module – $7.98
Elenco 300-in-One Electronic Project Lab = $3 thrift store find
(w/ the exception of some IC’s and other specified components, all of my parts came from this electronics kit)
Resistors = 1k,100k, 47k, 10k x 3, 1M (elenco)
Capacitors = 100uf, 47nf x2, 10uf, 2.2uf, 10nf (Elenco)
IC = PT2399 = $5.49 / 10 = $0.54
Q1 7805 = $0.43
P1 = 22k = $0.95
P2 = 100k = $0.69
• 4017 IC $0.51
• 555 timer IC (electronics kit)
• 8 small LED’s = $0.25 x 8 = $2.00
• 10 kΩ resistor (electronics kit)
• 1 MΩ resistor (electronics kit)
• 0.1 µF capacitor (electronics kit)
• Coupling capacitor, (electronics kit)
• Ten 1k resistors (electronics kit)
• 100k potetiometer 100k = $0.69
NPN transistor x 8 (electronics kit)
1k resistor x 8 (electronics kit)
1/8Inches 3.5mm Mono Audio Female Jack Socket Panel Mount Solder Lot = $11.37
BLACK MARKET MODULAR PATCH CABLE 5-PACK (3.5MM / 1/8″ MONO CABLES) = ($8.99×2 )= 17.98
Knobs – $3
Old poker chip case = $5 CL
ribbon cable = free scrap / resuse
Vintage Canon Calculator – $2 thrift find
Marine Control panel = $0.00 scrap find / repurpose
Parrot messaging switchplate (sampler) – $1 thrift find
Black plastic – $0.00 free scrap / repurpose
wood – $0.00 / free scrap / repurpose
screws – $0.00 scrap / repurpose
hook up wire spool = $2.50
RadioShack Dual Mini board = ($2.49×2) = 4.98
black spray paint scrap = $2
crazy glue = $1 dollar tree
Total = $67.62
drill soldering iron
Time (will need lots of)
optional = Table saw, clamps, 3rd arm, extra time
Caution! The 4017 IC is CMOS, and therefore sensitive to static electricity!
Any single-pole, single-throw switch is adequate. A household light switch will work fine, and is readily available at any hardware store.
The audio detector will be used to assess signal frequency. If you have access to an oscilloscope, the audio detector is unnecessary.
The model 4017 integrated circuit is a CMOS counter with ten output terminals. One of these ten terminals will be in a “high” state at any given time, with all others being “low,” giving a “one-of-ten” output sequence. If low-to-high voltage pulses are applied to the “clock” (Clk) terminal of the 4017, it will increment its count, forcing the next output into a “high” state.
Build the led sequencer circuit and attach it to the boat switch attached to the yamaha pss-140. There is a green line attached to the chasis – this is ground. The positive can be found using a volt meter. To trigger the drums connect a 1k resistor in series w/ the NPN transistors, the middle leg will be going out to the drum triggers of the yamaha (see photos they are the jumper lines in a single file) and the collector goes to the outputs of the 4017 counter. The other line is all connected together and then out the the first diode to the left of the drum contact points (see photos = yellow alligator clip) To attach to the 1/8″ mono jacks just solder them in series.
I also used a rotary position switch in series w/ resistors to very the tempo / bpm, u can experiment w/ different values
To build the Echo unit
Build the echo unit from this schematic and attach it to the boat switch panel. The LTC module requires 5v so I used a voltage regulator to distribute power to both IC’s. Connect the input to the melody output of the yamaha sound chip (pin 19 see data sheet) and the rhythm output (20) back to the rhythm output.
Yamaha PSS 140 Data Line Bend.
Cut the data lines between the main IC and the sound chip, attach to leg of the 1/8″ mono jacks, now you can patch the any outputs to any inputs.
To cut the keyboard in half, take your time & cut your keyboard in half, I used a hand saw.
next you will want to desolder the ribbon connecting the keyboard to the main circuit board and attach a longer computer ribbon
To assemble the LED screen from the calculator, first cut it out
there are 13 pins. pin 1 is ground, last pin is +, my display worked best w/ 6volts but I gave it 9 because 5 was too low & I couldn’t find 6 coming out of the keyboard. 23458910 correspond to the different legs of the LED Matrix. all you need to to is connect a wire to +. If you tap into the 4017 counter you can get the LED’s to display a pattern.
in the case of the pss1-40 the xtal / clock is right next to the sound chip (in the video!) – its silver and connected to a capacitor – attach the out of the new clock there.
To put the keyboard in the case, I did by eye w/ mininal measuring – your case may be different, mine was an old poker chip case, you can also use bbq brush cases. There are no rules, just attach as you see fit. have fun
once you have everything built and have tested that its working you can assemble into the keyboard, and then into the case!
Enjoy your new synth!