Tentative de Réparation d'un BF1

This page shows the circuit diagram for a simple audio amplifier

This board uses a LM 386 audio amplifier I.C.



Components marked with a "*" are optional, are usually not be needed.

The only components that you may want to use are the 22uF cap and the resistor RG, they are used to control the gain on the I.C., the I.C. has a gain of 20 without any components between pins 1 and 8.

If you need more gain you can add the cap and resistor to have as much gain as 200 !

e.g.

For a gain of 50 use a 680 Ohm

For a gain of 100 use a 180 Ohm

For a gain of 200 use only the capacitor ( do not add a resistor)

The power supply voltage ( VS ) can be between 5-12 Volts DC

You can use any type of speaker, but a 8 or 16 Ohm can produce the highest volume level on this I.C.

This board can be used for signal tracing during radio fault finding, i actually use this very circuit when i am trying to locate an audio signal during fault finding.

A technique for debugging a 9 volt stompbox circuit (Audio Probe)

There's a really cool way to debug your circuit besides the look and guess/measure with voltmeter technique. This gift was given to me by my friend Craig Ochikubo. (from "uncle Jimmy")

You take a plain old amp cord, cut off the 1/4" connector. Put a .1uF non polarized capacitor on the hot lead, put the shield/ground to the ground of your circuit. (If you use alligator clips, then the shield clip goes to ground) Now plug the other end into an amp and turn the volume low. News Flash - New Improved Audio Probe from R.G. Keen!

Now you can use the tip of the capacitor to probe around the circuit. You can hear how the circuit works by touching different places in the circuit. Start from the input of your stompbox and work your way through the circuit. Follow the signal path to see where your problem lies.

You can plug your guitar into the circuit and have someone else strum it while you probe OR you can use a signal generator or a keyboard or a CD player etc.... to send signal into the circuit. You can hear the effect change the tone of the input signal.

This simple technique can alert you to cold solder joints, if you hear audio before a joint, then none right after, it's probably a cold solder joint. You can hear how a transistor is amplifying the audio. There is a lot you can learn by probing around the circuit!

I have debugged all my circuits using a combination of the above. Once you get used to using the Audio Probe, debugging a circuit becomes pretty easy.

tu as vu avec Basstyra du forum ?
Il serait peut être intéressé mais je sais qu'il est assez overbooké.

shagg

Ouais je lui ai demandé par mp mais pas de réponses...