Happy new year around the world!
Please help, i have lanzar 2000opti drive. The problem is distorted output signal, if i injected 100hz sine wave, it produces sawtooth like waveform at speaker terminal at 100hz also. Looking waveforms at +in of driver board i have a perfect audio signal but at -in shows a sawtooth like waveform with the same frequency. I believe speaker out follows -in signal
I dont have sch. Please help and happy new year!
Please help, i have lanzar 2000opti drive. The problem is distorted output signal, if i injected 100hz sine wave, it produces sawtooth like waveform at speaker terminal at 100hz also. Looking waveforms at +in of driver board i have a perfect audio signal but at -in shows a sawtooth like waveform with the same frequency. I believe speaker out follows -in signal
I dont have sch. Please help and happy new year!
Is this one of the clones with the fan between the driver board and the two inductors?
Yes perry! Thank u!!
I don't have a diagram for this amp but I should have something close. Email me.
babin_perry@yahoo.com
The 6th pin from the 'RCA' end of the amp on the driver board should transition from near positive rail voltage to near ground after the mute delay. Is that happening in this amp?
babin_perry@yahoo.com
The 6th pin from the 'RCA' end of the amp on the driver board should transition from near positive rail voltage to near ground after the mute delay. Is that happening in this amp?
I don't have a diagram for this amp but I should have something close. Email me.
babin_perry@yahoo.com
The 6th pin from the 'RCA' end of the amp on the driver board should transition from near positive rail voltage to near ground after the mute delay. Is that happening in this amp?
Yes perry, It happens. Transition from +75 to gnd
.
Previous history of this amp, the + rail accidentally touch to heat sink through drain output transistor
It play for a minute then blow out the negative rail bulk caps. I replaced defective capacitors.
You got.mail.
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After I replaced the 2 identical BJT driver of the driver board(MPSA42), the amp gives a good music for few seconds then started to hear weird sound, the power supply current start to fluctuates high and low and these transistor becomes very hot.
I'm thinking I bought a counterfeit transistors I used 2N5501 and KPSA42(replacement maybe) but no luck.
Any input?
I'm thinking I bought a counterfeit transistors I used 2N5501 and KPSA42(replacement maybe) but no luck.
Any input?
Did the output transistors fail?
No, still working. If I heard a whizz/pump sound and the pre driver transistor gets hot I turned it OFF. Powered it ON, sounds nice again after a few seconds, start to have a pump/whizz sound again. The power supply current cycled high and low.
Were the holes drilled to remove conductive fiberglass material?
yes, I created holes surrounding the transistors and in between legs. To decrease conductivity and increase air flow through transistors.
To get better air flowing over the transistors, you install them with long leads so that they're nearer the fan.
This is very clever idea. If I have time I'll do this.
Perry I have more question, Is it safe to used 2n5501? I don't have original MPSA42, instead I used the 2n series.
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I don't know. I've never used the 5501. From the specs, it appears that it would be OK but specs (for as much as I can understand them) don't tell everything.
One more thing... In some amps, they use better inductors that don't run hot. For those amps (clones like these), you can turn the fan around and blow it on the board directly.
One more thing... In some amps, they use better inductors that don't run hot. For those amps (clones like these), you can turn the fan around and blow it on the board directly.
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