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Cymball:

The Cymball circuit includes the both Cowbell oscillators. To adjust these two oscillators you need an oscilloscope. If you don't have one you can use your computer sound card  as a oscilloscope with this small software SoundCard Oscilloscope. Prepare all components before assembly. List of components:

Image

Description

Part

Value

Qty

Polyester capacitor (2A183J)

C1*, C4*, C5*

18n

3

Polyester capacitor (2A103J)

C2*, C3*, C55*, C56*, C58*, C90*

10n

6

Polyester capacitor (2A223J)

C6*, C42*, C44*, C46*

22n

4

Polyester capacitor (2A332J)

C10*, C15*, C16*, C49*, C57*

3.3n

5

Polyester capacitor (2A682J)

C13*, C14*

6.8n

2

Polyester capacitor (2A152J)

C36*, C43*, C47*, C48*, C50*, C59*

1.5n

6

Ceramic capacitor (221)

C77*

220p

1

Polyester capacitor (2A102J)

C11*, C51*, C52*, C53*, C54*

1n

5

Electrolytic capacitor

C12*

100/10

1

Electrolytic capacitor

C35*

47/16

1

Electrolytic capacitor

C37*, C45*

2.2/50

2

Electrolytic capacitor

C38*, C40*, C41*

1/50

3

Electrolytic capacitor

C39*

0.47/50

1

Electrolytic capacitor

C78*

33/25

1

Diode

D5*, D6*, D7*, D8*, D11*, D12*

1N4148

6

NPN Silicon Transistor

Q2*, Q9*, Q16*, Q17*, Q18*, Q19*, Q20*, Q25*

2SC945

8

PNP Silicon Transistor

Q6*

2SA733

1

1/4w Carbon resistor

R3*, R10*, R55*, R83*, R87*, R104*, R108*, R112*, R119*, R124*, R126*

22K

11

1/4w Carbon resistor

R6*, R61*, R84*, R120*, R121*, R89*

10K

6

1/4w Carbon resistor

R15*

4K7

1

1/4w Carbon resistor

R35*, R37*, R39*, R46*, R48*, R50*

120K

6

1/4w Carbon resistor

R40*, R41*

560K

2

1/4w Carbon resistor

R42*

680K

1

1/4w Carbon resistor

R43*

220K

1

1/4w Carbon resistor

R44*

150K

1

1/4w Carbon resistor

R45*, R123*

100K

2

1/4w Carbon resistor

R52*, R88*, R90*, R91*, R92*, R105*

33K

6

1/4w Carbon resistor

R53*, R166*

1K

2

1/4w Carbon resistor

R56*, R58*

560R

2

1/4w Carbon resistor

R57*, R127*, R59*

82K

3

1/4w Carbon resistor

R60*

5K6

1

1/4w Carbon resistor

R85*, R95*, R86*, R98*, R101*

100R

5

1/4w Carbon resistor

R93*, R128*

470K

2

1/4w Carbon resistor

R94*, R114*, R115*, R110*

39K

4

1/4w Carbon resistor

R96*, R97*, R99*, R100*, R102*, R103*

1M

6

1/4w Carbon resistor

R106*

6K8

1

1/4w Carbon resistor

R107*, R111*, R109*, R113*

18K

4

1/4w Carbon resistor

R118*

47K

1

1/4w Carbon resistor

R125*

2K2

1

1/4w Carbon resistor

R129*

15K

1

Trim potentiometer (254P)

TM1*, TM2*

250KB

2

Hex schmitt trigger

U1

4584N

1

Dual Operational Amplifier

U3, U5

µPC4558C

2

Potentiometer (B205)

VR2*

2MB

1

Potentiometer (B203)

VR4*

20KB

1

Potentiometer (A104)

VR6*

100KA

1

 


Montages:


Here's the part that concerns the Cymball. You see that there are more components than in the previous section, this is why you must be careful that you do.

Assembly the resistors. If you can not find the location of a resistor, use Eagle.

Solder each value one after the other.

Solder TM1* and TM2*.

Solder the 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  4558s 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 potentiometers on the  opposite side of components.

DO NO WRONG IN THE VALUES OF POTENTIOMETERS, ALL THREE POTENTIOMETERS  ARE DIFFERENT.


 

 

Connect the power transformer. Connect your oscilloscope on R44 * as shown in the picture.

Adjust TM1* up to  a period of 1.85ms. If  TM1* adjustment range  is not large enough for this period change the value of R44 * per a resistor of 100Kohm. (supplied in kit)
Then connect your oscilloscope on R45 * as shown in the picture.

Adjust TM2 *  up to a period of 1.25ms. If  TM2* adjustment range does not allow you to get this period change the value of R45 * per 68kohm. (Supplied with the kit).

THEN DONT FORGET TO DISCONNECT THE POWER TRANSFORMER.

You can then go to HitHats assembly