Blown amp worth fixing?

mulletdude · 13th September 2010, 03:39 AM

Hello i have the lightning audio LA1.300.2 amplifier car audio
It will turn on temporarily but after about 5 seconds it will go into protect mode. any suggestions on what to check? or should it just be tossed?

Perry Babin · 13th September 2010, 03:42 AM

It probably has shorted output transistors. I'm assuming that it does this with no speaker wires connected to the speaker terminals and no RCAs plugged into the amp.

mulletdude · 13th September 2010, 03:44 AM

yeah it still does the same thing. i just looked inside and also see what appears to be a blown resistor and the glue they use to hold caps in is discolored around a couple jumper wires. could it be electrical arking causing this?

Perry Babin · 13th September 2010, 03:51 AM

The discoloration of the light-brown colored fixative is generally due to the breakdown of the fixative and not generally due to anything on the board.

Check the outputs to see if any are shorted.

mulletdude · 13th September 2010, 03:57 AM

L- to R+ show .8 ohms resistance all others show no short

Perry Babin · 13th September 2010, 04:00 AM

Those are the speaker terminals. You need to check the output transistors. If you're new to repair work, read the basic amp repair page (link below).

mulletdude · 13th September 2010, 04:04 AM

no link..

mulletdude · 13th September 2010, 04:09 AM

new info the sub gets straight DC for a few seconds after power on then the amp goes into protect mode

mike49504 · 13th September 2010, 05:32 AM

If theres DC Voltage on the speaker output terminals. Then you have blown output transistors.

jol50 · 14th September 2010, 02:46 AM

The outputs are connected to the speaker terminals, use a DMM to find them if you can't see the traces. They will be on the sink. Look up the number on them see if they are cheap to buy. Some are, some not. If you start it carefully you should not blow them again if something else is wrong, but it might only need those.

13th September 2010, 03:39 AM	#1
mulletdude diyAudio Member Join Date: Jun 2008	Blown amp worth fixing? Hello i have the lightning audio LA1.300.2 amplifier car audio It will turn on temporarily but after about 5 seconds it will go into protect mode. any suggestions on what to check? or should it just be tossed? __________________ Bigger the better... unless you like peace and quiet... But we can fix that too.

13th September 2010, 03:42 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It probably has shorted output transistors. I'm assuming that it does this with no speaker wires connected to the speaker terminals and no RCAs plugged into the amp. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

13th September 2010, 03:44 AM	#3
mulletdude diyAudio Member Join Date: Jun 2008	yeah it still does the same thing. i just looked inside and also see what appears to be a blown resistor and the glue they use to hold caps in is discolored around a couple jumper wires. could it be electrical arking causing this? __________________ Bigger the better... unless you like peace and quiet... But we can fix that too.

13th September 2010, 03:51 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The discoloration of the light-brown colored fixative is generally due to the breakdown of the fixative and not generally due to anything on the board. Check the outputs to see if any are shorted. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

13th September 2010, 03:57 AM	#5
mulletdude diyAudio Member Join Date: Jun 2008	L- to R+ show .8 ohms resistance all others show no short __________________ Bigger the better... unless you like peace and quiet... But we can fix that too.


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13th September 2010, 04:00 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Those are the speaker terminals. You need to check the output transistors. If you're new to repair work, read the basic amp repair page (link below). __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

13th September 2010, 04:04 AM	#7
mulletdude diyAudio Member Join Date: Jun 2008	no link.. __________________ Bigger the better... unless you like peace and quiet... But we can fix that too.

13th September 2010, 04:09 AM	#8
mulletdude diyAudio Member Join Date: Jun 2008	new info the sub gets straight DC for a few seconds after power on then the amp goes into protect mode __________________ Bigger the better... unless you like peace and quiet... But we can fix that too.

13th September 2010, 05:32 AM	#9
mike49504 diyAudio Member Join Date: Sep 2006	If theres DC Voltage on the speaker output terminals. Then you have blown output transistors.

14th September 2010, 02:46 AM	#10
jol50 diyAudio Member Join Date: Nov 2007	The outputs are connected to the speaker terminals, use a DMM to find them if you can't see the traces. They will be on the sink. Look up the number on them see if they are cheap to buy. Some are, some not. If you start it carefully you should not blow them again if something else is wrong, but it might only need those.

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