Is this the correct part ?
I’m ordering a replacement for the original
https://www.mouser.com/ProductDetail/Nexperia/74HC02D653?qs=P62ublwmbi9%2BB/a1jq/DZA==
I’m ordering a replacement for the original
https://www.mouser.com/ProductDetail/Nexperia/74HC02D653?qs=P62ublwmbi9%2BB/a1jq/DZA==
Back to this amp .
I replaced the driver ic ,U108,U107,Q111
Still no change amp has very distorted output .
Wondering if Q101 might be defective or what might be causing the amp to lose drive on pins 12,14 of the 2010
I replaced the driver ic ,U108,U107,Q111
Still no change amp has very distorted output .
Wondering if Q101 might be defective or what might be causing the amp to lose drive on pins 12,14 of the 2010
It could be but when I asked you to calibrate your probe to see if that was why you were not getting what I expected, I didn't get a reply. You can replace it but I don't like to tell anyone to replace a part unless there is some evidence that the part is actually defective.
I replaced it and didn’t change anything .
I guess I’m gonna take the board out of the heatsink and test it and post the waveform on the collector
I guess I’m gonna take the board out of the heatsink and test it and post the waveform on the collector
Scope is set to 5us 20volts div if I use any other scope setting the bottom of the waveform goes off the screen .
The 2nd pic is of the probe on the calibration pin of the scope .
The settings are .5ms .5 volts div
The 2nd pic is of the probe on the calibration pin of the scope .
The settings are .5ms .5 volts div
Attachments
I don’t know what’s causing the distorted output .
If I take the board out of the sink the amp plays clean audio .
Put the board back in the sink and the distorted audio returns .
If I take the board out of the sink the amp plays clean audio .
Put the board back in the sink and the distorted audio returns .
If Q101 is the level-shifting transistor, the first image in post 66 isn't right. It should be a square wave that drives from the negative rail to about 10v above the negative rail.
What did you do to go from the image in post 58 to the one above?
Does this go to a square wave when the amp is producing clean audio?
What did you do to go from the image in post 58 to the one above?
Does this go to a square wave when the amp is producing clean audio?
Back to this amp . There are 2 ground wires that connect to the heatsink on this amp I’m assuming the secondary ground wires to eliminate noise .
If I leave the 2 wires disconnected from the heatsink the amp will play clean audio but in a vehicle there is a loud hum . If I reconnect the wires I get very distorted audio again .
Any ideas what might cause this ?
If I leave the 2 wires disconnected from the heatsink the amp will play clean audio but in a vehicle there is a loud hum . If I reconnect the wires I get very distorted audio again .
Any ideas what might cause this ?
Secondary?
Yes. They are typically connected to ground through a capacitor.
Have you confirmed that the RCA shields for the head unit read 0 ohms to the case of the head unit?
Yes. They are typically connected to ground through a capacitor.
Have you confirmed that the RCA shields for the head unit read 0 ohms to the case of the head unit?
A hum in a vehicle is odd. Are you using any sort of inverter or battery charger?
On the bench, did the amp work perfectly with the wires connected AND with them disconnected?
Outside of the heatsink, does the amp work normally?
On the bench, did the amp work perfectly with the wires connected AND with them disconnected?
Outside of the heatsink, does the amp work normally?
On the bench the amp did not work correctly until the wires were disconnected . Outside of the sink the amp works normally it’s only when you connect the wires to the heatsink is when the problems exist . Not using an inverter or battery charger
Is there a capacitor blocking DC in series (on the board) for the 2 wires?
When in the heatsink, is there any significant noise or DC on the heatsink (wires disconnected)?
When in the heatsink, is there any significant noise or DC on the heatsink (wires disconnected)?
I may not be qualified to comment on this, but many years ago I worked on a power acoustik hammer series amp that had the same symptoms your amp is having. I even put it to the side where it sat for a few years because I couldn’t figure it out.
The issue causing the problem was a faulty isolation pad, there were no visible signs of a breach but somehow one single output transistor was shorted to the case. I replaced that pad and the amp worked great for years in a relatives vehicle.
The issue causing the problem was a faulty isolation pad, there were no visible signs of a breach but somehow one single output transistor was shorted to the case. I replaced that pad and the amp worked great for years in a relatives vehicle.