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Assembly and Operating Instructions for Kits


Parts for the Delay Timer 2s (DU2s)


Assembly instructions for other kits



Below is a list of the parts supplied with the Delay Timer 2s kit. Click on the photos for larger images.


We may occasionally make changes to the parts list without notice in order to improve the product.


Name/Description Quantity


PC board 1 PCB

The board label may be DU2 v1a or v1b.

Assembly instructions apply to either version.

Resistors (fixed value)

Click here for replacement parts.

470-Ω resistor 3

470-ohm resistor


680-Ω resistor 2

680 ohm resistor


1-kΩ resistor 4

1k resistor


22-kΩ resistor 2

22k resistor


100-kΩ resistor 1

100k resistor


1-MΩ resistor 1

1M resistor




Click here for replacement parts.

0.0047 μf 2 0.0047-uf capacitor 472
0.047 μf 2 0.047-uf capacitor 473
0.1 μf 1 0.1-uf capacitor 104
0.47 μf 1 0.47-uf capacitor  
10 μf 1 10-uf capacitor  

Semiconductors and sockets

Click here for replacement parts.

Silicon-controlled rectifier


1 EC103D SCR

SCR pins

C = cathode (-)

G = gate

A = anode (+)

IC556 timer IC

1 556 timer

556 timer pins

Note the location of pin 1 relative to the notch on the IC.

14-pin socket for above 1 14-pin socket  
2-stage optocoupler 1 PS2501-2

PS2501-2 pins

A white dot on the IC marks the location of pin 1.

8-pin socket for above 1 8-pin socket  

Panel mount parts

Click here for replacement parts.



red LED  
LED holder 3 LED holder  
Toggle switch 2 SPDT switch (red)  
Pushbutton, momentary, normally open 1 pushbutton switch  
RCA panel jack 2 RCA panel jack  
3.5mm mono panel jack 2 3.5mm mono panel jack  
3.5mm stereo panel jack 1 3.5mm stereo panel jack  
100 kΩ pot 1 linear taper pot  
1 MΩ pot 1 linear taper pot  
Pointer knobs 2 knob  

Project box with screws for lid

1 project box



9-V battery holder

(includes hook and loop tape)

1 laydown battery holder  
3/4-in standoffs 4 Standoffs  
1/4-in 4-40 bolts 8 Bolts  
1/4-in plastic tubing 2 in poly tube  
3/32" heat-shrink tubing 2 in heat-shrink tubing  
Label for top 1 Top label  
Printed template 1 Template

for the underside of the lid of the project box

Lengths of various colors of hook up wire are also included.




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