Six_Shooter
- Nov 16, 2012
- 98
- Joined
- Nov 16, 2012
- Messages
- 98
I have an OEM amplifier for my truck that I would like to finally get back to working condition, been putting it off for months since I discovered the problem...
Well I discovered this was an issue after the battery would be discharged overnight or so, and found it to be the OEM amplifier being the culprit. It was drawing about 400mA (discharge rate difference between the amp being connected and disconnected) or so when it was attached to vehicle and using my Fluke DMM at the battery while looking for the problem.
Today I decided to get working on it, and when it was connected to my bench supply was indicating about 375mA without being turned on, just power and ground. There is a separate turn on trigger that should be what turns it on and off.
Anyway, I've traced it down to what I believe is a MOSFET that is what switches the power on to the amplifier ICs, of which there are 3. Once this was removed the current draw went to zero. One side is connected to the 12V input, one pin is connected to a transistor through a resistor that is controlled by the trigger input. The third pin is what then feeds the 3 amplifier ICs.
I don't know what to make of the markings to start looking for a datasheet to find a replacement, so if some of you electronics gurus can take a look and help me identify this transistor, I would be really appreciative.
I guess barring finding the original specs knowing what I need to do to spec out a new part to replace it with. From what I understand a MOSFET makes the most sense here to pass relatively high power.
Anyway, onto the pictures. It is Q701, just to the right of the large diode. I have also included pictures of the transistor itself and what the pads on the board look like with it removed to help in identifying a replacement.
Don't worry about the Q702, that is the transistor that is controlled by the trigger input, and then triggers this mystery transistor (MOSFET?), you'll notice in one picture Q702 is removed and then replaced in another, it was an initial idea of what was keeping the amplifier powered up. Also C706 has been removed for easier access to the offending transistor (and follow traces).
Thank you.
Well I discovered this was an issue after the battery would be discharged overnight or so, and found it to be the OEM amplifier being the culprit. It was drawing about 400mA (discharge rate difference between the amp being connected and disconnected) or so when it was attached to vehicle and using my Fluke DMM at the battery while looking for the problem.
Today I decided to get working on it, and when it was connected to my bench supply was indicating about 375mA without being turned on, just power and ground. There is a separate turn on trigger that should be what turns it on and off.
Anyway, I've traced it down to what I believe is a MOSFET that is what switches the power on to the amplifier ICs, of which there are 3. Once this was removed the current draw went to zero. One side is connected to the 12V input, one pin is connected to a transistor through a resistor that is controlled by the trigger input. The third pin is what then feeds the 3 amplifier ICs.
I don't know what to make of the markings to start looking for a datasheet to find a replacement, so if some of you electronics gurus can take a look and help me identify this transistor, I would be really appreciative.
I guess barring finding the original specs knowing what I need to do to spec out a new part to replace it with. From what I understand a MOSFET makes the most sense here to pass relatively high power.
Anyway, onto the pictures. It is Q701, just to the right of the large diode. I have also included pictures of the transistor itself and what the pads on the board look like with it removed to help in identifying a replacement.
Don't worry about the Q702, that is the transistor that is controlled by the trigger input, and then triggers this mystery transistor (MOSFET?), you'll notice in one picture Q702 is removed and then replaced in another, it was an initial idea of what was keeping the amplifier powered up. Also C706 has been removed for easier access to the offending transistor (and follow traces).
Thank you.
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