power bass 1500

timwebb · 25th April 2011, 01:30 AM

ok i have this amp the guy who had it touched the speakers and it fried the power supply. what would cause the amp not to power up at all?

mike49504 · 25th April 2011, 01:48 AM

It could be a few different things.

Did you check the reverse polarity diode (usually located behind the power and ground connections.

Could be an open trace .

What are the voltages you have on the power supply IC ?

amc32 · 25th April 2011, 04:28 AM

If this guy touched the speaker outputs together and subsequently damaged the power supply section. I would look beyond the obvious damage and inspect the output section. Is this an amp you just recieved or is an amp your having problems with after said repair has been done?

Perry Babin · 25th April 2011, 08:24 AM

Assuming that you've already replaced all of the power supply components that were obviously defective...

Do you have 12v on the center legs of the power supply FETs?

timwebb · 25th April 2011, 11:29 PM

ok i got the amp to function right. it use irfz48 in the power supply with 100ohm resistor should i lower the gate resistors. the output transistors are 31n20's and wanted to if 9640' would work? and this is an amp i just got in.

Perry Babin · 25th April 2011, 11:35 PM

The 100 ohm gate resistors are likely a bit high for the Z48s. I'd suggest replacing them with resistors between 47 and 75 ohms. If you don't want to replace them and have a variable power supply, reduce the voltage to about 10.5v to see if the current increases or the Z48s get hot. If you see either of these, you must reduce the resistor value.

The 9640 isn't a sub for the 31N20D. There aren't many (none that I know of ) that will serve as a good sub for the 31N20Ds in all amps that use them.

timwebb · 26th April 2011, 12:01 AM

i thought that was high for the gate but thats whats in there when i got it.it came from ebay so who knows.

timwebb · 27th April 2011, 05:59 AM

ok i got the power supply working but when i put the out put transistors in it smokes two driver transistors.it looks to be the exact driver board i just fix on the power acoustic amp. its the same 2 drivers are failing on here.

Perry Babin · 27th April 2011, 07:04 AM

When those fail, they typically just open (no smoke). If they (or an adjacent resistor) smoked, I'd expect that there was another problem. Confirm that you don't have any solder bridges on the outputs.

timwebb · 27th April 2011, 08:28 PM

the two transistors are ksp56.can i use mps42 as the replacement?and it was a ball of solder between the two pads.

25th April 2011, 01:30 AM	#1
timwebb diyAudio Member Join Date: Jan 2010 Location: memphis tn	power bass 1500 ok i have this amp the guy who had it touched the speakers and it fried the power supply. what would cause the amp not to power up at all?

25th April 2011, 04:28 AM	#3
amc32 diyAudio Member Join Date: Mar 2008	If this guy touched the speaker outputs together and subsequently damaged the power supply section. I would look beyond the obvious damage and inspect the output section. Is this an amp you just recieved or is an amp your having problems with after said repair has been done? __________________ ...............I Hear in color.................

25th April 2011, 08:24 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Assuming that you've already replaced all of the power supply components that were obviously defective... Do you have 12v on the center legs of the power supply FETs? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

25th April 2011, 11:35 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The 100 ohm gate resistors are likely a bit high for the Z48s. I'd suggest replacing them with resistors between 47 and 75 ohms. If you don't want to replace them and have a variable power supply, reduce the voltage to about 10.5v to see if the current increases or the Z48s get hot. If you see either of these, you must reduce the resistor value. The 9640 isn't a sub for the 31N20D. There aren't many (none that I know of ) that will serve as a good sub for the 31N20Ds in all amps that use them. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

27th April 2011, 07:04 AM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	When those fail, they typically just open (no smoke). If they (or an adjacent resistor) smoked, I'd expect that there was another problem. Confirm that you don't have any solder bridges on the outputs. __________________ 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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25th April 2011, 01:48 AM	#2
mike49504 diyAudio Member Join Date: Sep 2006	It could be a few different things. Did you check the reverse polarity diode (usually located behind the power and ground connections. Could be an open trace . What are the voltages you have on the power supply IC ?

25th April 2011, 11:29 PM	#5
timwebb diyAudio Member Join Date: Jan 2010 Location: memphis tn	ok i got the amp to function right. it use irfz48 in the power supply with 100ohm resistor should i lower the gate resistors. the output transistors are 31n20's and wanted to if 9640' would work? and this is an amp i just got in.

26th April 2011, 12:01 AM	#7
timwebb diyAudio Member Join Date: Jan 2010 Location: memphis tn	i thought that was high for the gate but thats whats in there when i got it.it came from ebay so who knows.

27th April 2011, 05:59 AM	#8
timwebb diyAudio Member Join Date: Jan 2010 Location: memphis tn	ok i got the power supply working but when i put the out put transistors in it smokes two driver transistors.it looks to be the exact driver board i just fix on the power acoustic amp. its the same 2 drivers are failing on here.

27th April 2011, 08:28 PM	#10
timwebb diyAudio Member Join Date: Jan 2010 Location: memphis tn	the two transistors are ksp56.can i use mps42 as the replacement?and it was a ball of solder between the two pads.

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