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CowBell:
You will notice that all the names of components have a star to match the names on the original TR-808 schematic. The TR-808 have two different circuits for instruments (Main board and Voice board). As we have design a single circuit, we had components with same names due to the addition of the star. All components with a star in their name are the components of the TR-808 Voice board . Prepare all these components before beginning assembly. List of components:
Image | Description | Part | Value | Qty |
| Polyester capacitor (2A103J) | C28* | 10n | 1 |
| Polyester capacitor (2A223J) | C76* | 22n | 1 |
| Polyester capacitor (2A332J) | C29* | 3.3n | 1 |
| Polyester capacitor (2A222J) | C30*, C31* | 2.2n | 2 |
| Electrolytic capacitor | C32*, C33* | 10/25 | 2 |
| Electrolytic capacitor | C9* | 0.47/50 | 1 |
| Electrolytic capacitor | C34*, C75* |
1/50 | 2 |
| Diode | D1*, D2*, D3*, D4* | 1N4148 | 4 |
| NPN Silicon Transistor | Q1*, Q14*, Q15* | 2SC945 | 3 |
| PNP Silicon Transistor | Q5* | 2SA733 | 1 |
| 1/4w carbon resistor | R4*, R9*, R117* | 22K | 3 |
| 1/4w carbon resistor | R5*, R26*, R27* | 10K | 3 |
| 1/4w carbon resistor | R14* | 4K7 | 1 |
| 1/4w carbon resistor | R18*, R21*, R22* | 3K3 | 3 |
| 1/4w carbon resistor | R19*, R28*, R29*, R23* | 100K | 4 |
| 1/4w carbon resistor | R20* | 15K | 1 |
| 1/4w carbon resistor | R24*, R63*, R65* | 2K2 | 3 |
| 1/4w carbon resistor | R25*, R30*, R32* | 470K | 3 |
| 1/4w carbon resistor | R31*, R33* | 100R | 2 |
| 1/4w carbon resistor | R62*, R64*, R82* | 33K | 3 |
| 1/4w carbon resistor | R116* | 8K2 | 1 |
| 1/4w carbon resistor | R122*, R163* | 1K | 2 |
| Dual Operational Amplifier | U2, U6 | µPC4558C | 2 |
| Potentiometer (A502) | VR5* | 5KA | 1 |
Make it:
 | Here is the Cowbell. |
 | Solder all resistors. Solder each value one after the other. |
 | Solder the four diodes 1N4148 MAKE SURE DIODES ARE IN THE RIGHT WAY |
 | Solder polyesters capacitors |
 | Solder electrolytics capacitors MAKE SURE ELECTROLYTICS CAPACITORS ARE IN THE RIGHT WAY
|
 | Solder transistors.Do not get confused between 2SA733 and 2SC945 it is not the same transistors.
MAKE SURE TRANSISTORS ARE IN THE RIGHT WAY |
 |
Connect the power transformer. Test 4558 power supply before solder. The green dot is-15V, the red dot is +15 V (plus or minus 5%). You have the ground on the potentiometer big square pad . Always check that the four wires from the power supply is well connected.
THEN DONT FORGET TO DISCONNECT THE POWER TRANSFORMER. DO NOT SOLDER COMPONENT AS THE CIRCUIT IS POWERED ! |
 | Finally return the PCB and solder the potentiometer on the opposite side of components.
You can then go to Cymball assembly |
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