question about TL594 PWM signals - Page 2

NBBN_amplifiers · 17th August 2010, 08:28 PM

Hi,

I've been working with car audio AMPs for a long time. Looking at your problem it seems to me that you have some output stage mosfet or bipolar in short circuit.

Try to unplug the power supply and measure resistance in the output of the transistors. I assume that someone may be bad.

Since the circuit is generating DC to the other side of the toroid this is what may be happening...

grjr · 19th August 2010, 07:58 PM

Just to update the thread, I reconnected the preamp to the discrete amplifier and everything seems to be working good. Haven't ordered new parts to finish up the amplifier yet but I will do that soon. Still wondering if the waveform at the base of the D44H11 switching transistors is fine. Maybe if someone has an orion 222 sx lying around they could chime in. Thanks for your help Perry, it is very much appreciated

Perry Babin · 20th August 2010, 04:21 PM

I would expect the waveform to be more flat across the top. It may be better as the pulse width increases. Try decreasing the DC power supply voltage. That will cause the pulse width to increase.

17th August 2010, 08:28 PM	#11
NBBN_amplifiers diyAudio Member Join Date: Mar 2008 Location: Metuchen, NJ Blog Entries: 2	Some short in the audio output stage Hi, I've been working with car audio AMPs for a long time. Looking at your problem it seems to me that you have some output stage mosfet or bipolar in short circuit. Try to unplug the power supply and measure resistance in the output of the transistors. I assume that someone may be bad. Since the circuit is generating DC to the other side of the toroid this is what may be happening... __________________ Nickel

20th August 2010, 04:21 PM	#13
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	I would expect the waveform to be more flat across the top. It may be better as the pulse width increases. Try decreasing the DC power supply voltage. That will cause the pulse width to increase. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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19th August 2010, 07:58 PM	#12
grjr diyAudio Member Join Date: Sep 2007	Just to update the thread, I reconnected the preamp to the discrete amplifier and everything seems to be working good. Haven't ordered new parts to finish up the amplifier yet but I will do that soon. Still wondering if the waveform at the base of the D44H11 switching transistors is fine. Maybe if someone has an orion 222 sx lying around they could chime in. Thanks for your help Perry, it is very much appreciated

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