Video / ESS
video / ess

Sound and voice
sound and Voice


power supply
power supply


you are heresound

TRS2_03_SOU better view Click this picture to enlarge TRS2-03 SOU board.
If you want to identify an unknown board and need a better picture, view this full sized TRS2-03 SOU board image (size is 346 KB)
I80-02-SOU Click this picture to enlarge a TRS (I80)-02-SOU board with voice.
If you want to identify an unknown board and need a better picture, view this full sized I80-02-SOU board image (size is 409 KB)

Radar Scope had Voice!

Voice label TRS board When i repaired the older TRS01 board variant in my cocktail table i noticed a "VOICE" label on the sound board. I knew only voice-less SOU boards of TRS02 before.
label indicating voice board
Also, on this board there was a tester's label which was dated July 16, 1982 and which says (in german) "with speech"

The following table has some sampled voices i collected as ".wav" files. They were recorded using a sound card at 22,5 kHz, mono, by clipping a probe on the voice regulator pin:

Sample file Duration (seconds) Size (KB) Description Note
cp01_voice_a.wav 4.5 191 "trouble, trouble..." This is where the game starts
cp01_trouble.wav 6 265 (plus siren) trouble... siren and voice (mixed)
cp01_voice_b.wav 2.5 102 "...checkpoint charlie (?)" In wave, at the beginning (Part I)
cp01_voice_c.wav 2.5 94 "...checkpoint bravo" In wave, after about 60 s (Part II)
cp01_voice_d.wav 2.5 95 "...checkpoint alpha" In wave, after about 90 s (Part III)
1 52 "...Use caution!" Almost at the end of a wave. (Part IV)(Thanks to c.h for this info!)
cp01_voice_f.wav 2.5 94 "complete attack mission" End of wave
cp01_voice_g.wav 94 "engine trouble" constantly when damage 100%

The samples b to e above repeat every completed wave, while g sounds only when the damage meter has reached 100%

These are some samples of the regular game sound

Sample file Duration (about seconds) Size (KB) Description Note
p01_start.wav 9 394 siren sound from TRS02 (voiceless) version
p01_beep_and_background.wav 4 102 background sound start beep and beginning wave
p01_attack.wav 7 298 attacking alien from 1st wave
p01_shoot.wav 3 145 laser gun from 1st wave
(to be continued)

Sound board power in

SOU power in This is the 7P SOU plug, named [P4 power in] on the TRS SOU board edge. see also in the power supply section.

Signals on the sound board

Here is what i found out so far about the sound hardware. I used a "TRS2-03-SOU" card, labeled S-02316. A "TRS2-04-SOU" looks the same but mine has the 8035 and the EPROM chip soldered onto the board (i.e., not in a socket) so i took the former for testing.

Sound board signals
Location Signal Name Signal description
P4 CPU - pin 1 Noise From separate noise generator, generates flickering of the stars. The "shot noise" is an electronic noise, generated by the flow of electrons through a highly-charged field (like a semiconductor junction). Here it is the inversely polarized base-collector junction of the NPN transistor (Tr 10). This transistor has its collector left open. The shot noise is not used for sound purposes but for a visual effect: it generates a random twinkling of the stars in Radar Scope (The Noise signal at P4 is labeled /STAREN on the CPU board and used to randomly switch the stars on and off)
P4 CPU - pin 2 N.C. Not connected
P4 CPU - pin 3
Output from sound board 8035 MCU, PB4 (Pin 35) going to the CPU board. This signal acknowledges the execution of the startup sound sequence. The line is held high (for about 8 seconds after the Start button has been pressed) then pulses low three times after completion of the startup siren sounds. ANS-I is renamed to
on the CPU board (Its L active low signal of the 8035 is inverted two times on the CPU Board)
P4 CPU - pin 4
This comes from the CPU board and goes to the active low /INT line of the sound board MCU. During the initial startup sound (for about 8 seconds after the Start button has been pressed) this line is pulled low by the CPU
P4 CPU - pin 5 GND ground
8035-pin11 ALE ALE is Adress Latch Enable, an output of the 8035. It occurs every cycle of the 8035 and you can use it as a clock output for connecting a signal analyzer. For example, when ALE goes low, an adress will be latched by the 74LS75 for IC19, which is the 2716 EPROM
P5 CPU - pin 5; 8035-pin4
Reset Input from CPU board, also resets the LS164 (serial in / parallel out) shift register on the sound board
P5 CPU - pin 14; IC17-pin8 2VF goes to the clock inputs of the LS164 shift register and is used for the explosion sound
P5 CPU - pin1
to DB0 - pin 12 - of 8035
Synth Sound Data for MCU see table below
P5 CPU - pin2
to DB1 - pin 13 - of 8035
Synth Sound Data for MCU see table below
P5 CPU - pin3
to DB2 - pin 14 - of 8035
Synth Sound Data for MCU see table below
P5 CPU - pin4
to DB3 - pin 15 - of 8035
Synth Sound Data for MCU see table below
P5 CPU - pin6 /SOUND0 Sound trigger, going to IC9-pin1. Used for explosion sound; scratching noise
P5 CPU - pin7 /SOUND1 Sound trigger, going to IC9-pin3. Used for muting (?) of noise
P5 CPU - pin8 /SOUND2 Sound trigger, going to IC9-pin5. Used for noise
P5 CPU - pin9 /SOUND3 This goes to PB5 of the 8035. Used for ?
P5 CPU - pin10 /SOUND4 This goes to the T1 input of the 8035, pin39; It starts the burning ships sound of the aliens when they go down. Used like an interrupt
P5 CPU - pin11 /SOUND5 This goes to the T0 input of the 8035, pin1; It starts the attack sound of the aliens when they swoop down. Used like an interrupt
P5 CPU - pin12 /SOUND6 Goes to IC9-pin9; Makes chirping high-pitched background space noise
P5 CPU - pin13 /SOUND7 Goes to IC9-pin11; This is the siren trigger. The siren is built with the 556 timer chip

Synth Sound Data for MCU

The SYNTH0 to SYNTH3 inputs to the 8035 MCU on the sound board can select a total of 16 states for type of background sound the game will play.
The MCU will then output to the digital-to-analog converter DAC-08 at position 1H. This DAC together with one half of the operational amplifier MB3614 (pos. 2G) forms a high speed wave generator. The output of the wave generator is mixed into the other sound output lines at R1. This is the 10K variable resistor marked "CPU / VR1" you see at the top left of the Radar Scope sound board.

This table shows the 4 bit words and their uses:

For example, when the CPU (Z80 on CPU board) outputs a $04 for the sound board, this lower nibble ($4 = 0100) will be inverted and appear as (1011) to SYNTH3-0. In the 4 columns to the left of the table you see the SYNTH data (1011) and in the rightmost column $04. P=01,04,07... means that this sound is heard in all phases (P) 01,04,07 and so on, and in the first part of the phase. Each P has four parts, increasing in difficulty. The overall style of the attack sound is the same, but the sound is sligthly different for each of the red 1,4,7..., magenta 2,5,8... and gold 3,6,9... colored P's.

Click on the wav sample links in the table below to hear how the settings for SYNTH0 to 3 apply. Each sample is about 4 seconds, about 200KBytes long.

SYNTH3 SYNTH2 SYNTH1 SYNTH0 sample comment
0 0 0 0 synth0000.wav fast two tone background, part IV
0 0 0 1 synth0001.wav four tone background, part III
0 0 1 0 synth0010.wav fast two six background, part II
0 0 1 1 synth0011.wav slow two six background, part I

Siren circuit

The Radar Scope siren sounding at the start of the game is not a sampled sound produced by the waveform generator described above. It is created with one half of the NE556 dual timer at position 3B. This is an IC which has two of the common 555 timers in one casing.

The 555 part responsible for the siren is wired as an astable, the timing resistors being R50 (47k) and R51 (27k). The timing capacitor is 33nF. The output at pin 9 of the NE556 is a 432 Hz square wave. This square wave is modulated with about 185 Hz from the oscillator at position 3C (4049, pin 4) which is fed to the "control voltage" input of the NE556 at pin 11. It makes the siren sound a bit more rough/uneven.

The result is then switched by a slow oscillator formed with the 4049 at position 3A, making the siren "attack" in ramps of about 1 Hz.

Siren sound missing?

On a TRS2-04-SOU board, if you have the beep sounds but the siren is missing, follow the SOUND 7 sigal from where it comes into the board (see table below). It passes through an inverter (Pos. 2I) to the reset of the 556. So when SOUND 7 is low, the 556 Timer B will be enabled. Verify that this is working, check the 556 timer chip - output is pin number 9 - and the 4049 at position 3A. Check TR8 and TR9 as well as the electrolytic capacitors at C45 and C46.

Variants of the sound board

The sound board in my Radar Scope cocktail table (Model "TRS-HL") which is equipped with the voice option described above seems to be older than the TRS2 sound board used in upright machines (Model "TRS-UP-US").
The label reading "TRS-02-SOU" has a sticker. If it is removed, the printed text reads "I80-02-SOU". Maybe this board was also used in games before Radar Scope.(what does I80 mean?).

before removal of TRS labelbefore removal of the label

after removal of the labelafter