punch 100 dsm question

ben04srt · 7th June 2009, 02:16 PM

I replaced the outputs on this amp and I am still getting about 7 volts dc on the left channel output.

My question is would anything on the driver board cause this?
If so where on driver boards should I test?

Perry Babin · 7th June 2009, 05:01 PM

Do your driver boards have all of the resistors on one side and the transistors on the other side or are they mixed?

Is it drawing excessive current?

ben04srt · 7th June 2009, 09:49 PM

resistors on one side transistors on other.

it draws a good bit of current .

Perry Babin · 7th June 2009, 10:55 PM

Turn the bias pots fully counter-clockwise to see if the current draw decreases.

Check the parts highlighted on the following images.
http://www.bcae1.com/temp/db1.jpg
http://www.bcae1.com/temp/db2.jpg

ben04srt · 12th June 2009, 04:11 PM

Replaced the transistors on the driver board along with the resistors.
Pots are turned all the way down.
The dc voltage in not 7 volts anymore it is less than 1 volt.
The amp still draws excessive current.

Perry Babin · 12th June 2009, 05:26 PM

Clamp the transistors and power up the amp for just long enough to measure the DC voltage across the large 0.1 ohm source resistors. Which ones have more than 0.000v across them?

Do this with no audio. If you have a 2 ohm current limiting resistor, insert it in the B+ line.

ben04srt · 12th June 2009, 06:53 PM

Dc voltage is gone on left channel.
None of the source resistors have more than 0.000 on them.

amp still draws lots of current when remote voltage is applied

Perry Babin · 12th June 2009, 06:57 PM

How much current?

ben04srt · 12th June 2009, 07:41 PM

My multimeter is not letting me check amperage.

If I turn the power supply of and on a few times it turns the amp on, If I turn it off then back on only a few seconds after it was working it turns right on.

When I wait a few minutes to turn it back on is when I have to toggle it of and on.

Perry Babin · 12th June 2009, 08:04 PM

What are you using for a power supply?

If it's an AC-DC converter, what's it's amp rating?

How do you know it's pulling excessive current?

7th June 2009, 02:16 PM	#1
ben04srt diyAudio Member Join Date: Jul 2006 Location: Dover,ohio	punch 100 dsm question I replaced the outputs on this amp and I am still getting about 7 volts dc on the left channel output. My question is would anything on the driver board cause this? If so where on driver boards should I test?

7th June 2009, 05:01 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do your driver boards have all of the resistors on one side and the transistors on the other side or are they mixed? Is it drawing excessive current? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

7th June 2009, 10:55 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Turn the bias pots fully counter-clockwise to see if the current draw decreases. Check the parts highlighted on the following images. http://www.bcae1.com/temp/db1.jpg http://www.bcae1.com/temp/db2.jpg __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

12th June 2009, 05:26 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Clamp the transistors and power up the amp for just long enough to measure the DC voltage across the large 0.1 ohm source resistors. Which ones have more than 0.000v across them? Do this with no audio. If you have a 2 ohm current limiting resistor, insert it in the B+ line. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

12th June 2009, 06:57 PM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	How much current? __________________ 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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7th June 2009, 09:49 PM	#3
ben04srt diyAudio Member Join Date: Jul 2006 Location: Dover,ohio	resistors on one side transistors on other. it draws a good bit of current .

12th June 2009, 04:11 PM	#5
ben04srt diyAudio Member Join Date: Jul 2006 Location: Dover,ohio	Replaced the transistors on the driver board along with the resistors. Pots are turned all the way down. The dc voltage in not 7 volts anymore it is less than 1 volt. The amp still draws excessive current.

12th June 2009, 06:53 PM	#7
ben04srt diyAudio Member Join Date: Jul 2006 Location: Dover,ohio	Dc voltage is gone on left channel. None of the source resistors have more than 0.000 on them. amp still draws lots of current when remote voltage is applied

12th June 2009, 07:41 PM	#9
ben04srt diyAudio Member Join Date: Jul 2006 Location: Dover,ohio	My multimeter is not letting me check amperage. If I turn the power supply of and on a few times it turns the amp on, If I turn it off then back on only a few seconds after it was working it turns right on. When I wait a few minutes to turn it back on is when I have to toggle it of and on.

12th June 2009, 08:04 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What are you using for a power supply? If it's an AC-DC converter, what's it's amp rating? How do you know it's pulling excessive current? __________________ 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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