Clarion DPX11500 #2 Repair

[Perry Babin]

If you drive a strong signal into the amp (preferably a 50-100Hz sine wave) and vary the volume from 0 to near the maximum from the signal source, you should be able to see an AC voltage there that varies with the volume of the signal source.

[Zeptoplix]

Will ground to the negative terminal block be acceptable?

[Perry Babin]

If you're referring to the placement of the black meter probe, it should be OK. The negative speaker terminal may be a better choice.

[Zeptoplix]

I see 8V on one side and 15.36 on the other AC volts... Used a 50 hz tone... Gave a nice steady reading. Got worried when it started going crazy, but it turns out the sine was over and a song was next. Lol.

[Perry Babin]

Does your 12v DC power supply have an amp meter on it?

[Zeptoplix]

No.. I use a small 7Ahr 12V battery from an emergency light; With the head light to limit current.

[Perry Babin]

If you adjust the bias pot in the amp, does the headlight get dimmer/brighter?

Do this with the transistors clamped or watch their temperature VERY closely to make sure that they don't overheat.

[Zeptoplix]

The brightness did not change. I marked the position with a pencil and tried turning both directions.

[Zeptoplix]

Just found a resistor at R166 that is fairly dark, but tests ok at 100 ohm.

[Perry Babin]

You stated that you had ±25v on the output transistors. When you drive a strong signal into the amp, does that voltage become greater for either set of outputs?