T1.4000DL

Hexhclass

Member
2010-06-22 6:08 pm
usa
T1.4000DL SOUNDSTREAM

This amp came in with half the PS FET shorted and one high side output FET shorted.I replace all outputs.Amp is producing audio but it it drawing about nine amps at idle and the outputs are heating up fast.Q126,127,123,122,(MPSA56),I believe are the drivers i replace them with A92s.

Any idea what the problem could be?
Is it safe to power these amp without the driver board?
 

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I pull four A56 from an amp and install them along with the default resistor.Amp idle is at 1.2A.
I apply input signal and all seem ok.After about 10 minutes I could hear a sequel coming from the amp and it is starting to draw more current.The 200v caps by the filter caps are getting very hot and wave forms on the output FETs change.
I try it with the A92s and got same results.

same scope settings were used 20v/dv 10/us
high side leg 1 and 3
 

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