Thunder 6500D

mbates14 · 02:42 AM

Got a thunder 6500D I repaired it awhile back with new outputs, and it worked fine.

Guy drove it hard, blew the subs, and in turn blew the outputs up again in the amp.

Took the amp apart, replaced all 4 outputs and replaced both gate resistors. they were ok, but i changed them anyway. I used 52N20s in place of the 45N20s because i had no more 45N20s.

So after powering up, if the amp is REALLY low volume, low enough so you can still hear it, but only if the room is somewhat quiet. it sounds fine. soon as you turn it up, it starts to distort, pop, and crackle quite alot. the harder you push the amp, the worse it gets, and the SMPS inside the amp starts emitting noise as it goes. Plus when the bass hits, it pushes the subs inward when driven kinda hard. so something not right.

I pulled the drivers and the small SOT23 transistors and checked them out of circuit for opens, shorts, and leakages that shouldnt be. everything is ok. so i put it all back in.

Also the LM311 is getting kinda hot, so i replaced it anyway, still gets hot. the 2 SMD higher wattage resistors next to the LM311 get very hot. also 1 set of drivers get kinda warm as well, while the other driver set remains cool. the 18v and -18v regulated voltages appear to be present. i have both positive and negative 60V rails.

I am at a loss on this one. any ideas?

Perry Babin · 19th February 2010, 02:53 AM

These self oscillating amps are VERY sensitive to the outputs that you use. The ones you installed may not be compatible. Do you have any IRF3415s?

mbates14 · 19th February 2010, 03:03 AM

nope. none. just IRF3205s? I have IRF640s as well? and some IRF9640s? the 52N20 is a 45N20 with more current capability, i thought anyway...

Perry Babin · 19th February 2010, 03:09 AM

It's not the current rating that makes a difference. The only parts that I've found that work in these amps are the originals (but not all of the originals) or the 3415s. Others may work but I haven't had any luck finding any.

The 3205s can't withstand the voltage. The 640s can't handle enough current.

mbates14 · 19th February 2010, 03:19 AM

i used 42N20s in here before. they worked. but i only have 1 of those left, and i need 4. so i guess its off to digikey.

Perry Babin · 19th February 2010, 03:27 AM

They may not have been working perfectly. The amp may seem to work perfectly but they might be borderline. Looking back at my notes, I tried the IRFB42N20Ds and they didn't work.

mbates14 · 19th February 2010, 03:30 AM

well add the 52N20s hehe.

mbates14 · 19th February 2010, 03:34 PM

digikey doenst have the 3415s.

Perry Babin · 19th February 2010, 04:21 PM

IRF3415 - Octopart

19th February 2010, 02:40 AM	#1
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	Thunder 6500D Got a thunder 6500D I repaired it awhile back with new outputs, and it worked fine. Guy drove it hard, blew the subs, and in turn blew the outputs up again in the amp. Took the amp apart, replaced all 4 outputs and replaced both gate resistors. they were ok, but i changed them anyway. I used 52N20s in place of the 45N20s because i had no more 45N20s. So after powering up, if the amp is REALLY low volume, low enough so you can still hear it, but only if the room is somewhat quiet. it sounds fine. soon as you turn it up, it starts to distort, pop, and crackle quite alot. the harder you push the amp, the worse it gets, and the SMPS inside the amp starts emitting noise as it goes. Plus when the bass hits, it pushes the subs inward when driven kinda hard. so something not right. I pulled the drivers and the small SOT23 transistors and checked them out of circuit for opens, shorts, and leakages that shouldnt be. everything is ok. so i put it all back in. Also the LM311 is getting kinda hot, so i replaced it anyway, still gets hot. the 2 SMD higher wattage resistors next to the LM311 get very hot. also 1 set of drivers get kinda warm as well, while the other driver set remains cool. the 18v and -18v regulated voltages appear to be present. i have both positive and negative 60V rails. I am at a loss on this one. any ideas? Last edited by mbates14; 19th February 2010 at 02:42 AM.

19th February 2010, 02:53 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	These self oscillating amps are VERY sensitive to the outputs that you use. The ones you installed may not be compatible. Do you have any IRF3415s? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2010, 03:09 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It's not the current rating that makes a difference. The only parts that I've found that work in these amps are the originals (but not all of the originals) or the 3415s. Others may work but I haven't had any luck finding any. The 3205s can't withstand the voltage. The 640s can't handle enough current. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2010, 03:27 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	They may not have been working perfectly. The amp may seem to work perfectly but they might be borderline. Looking back at my notes, I tried the IRFB42N20Ds and they didn't work. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2010, 04:21 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	IRF3415 - Octopart __________________ 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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19th February 2010, 03:03 AM	#3
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	nope. none. just IRF3205s? I have IRF640s as well? and some IRF9640s? the 52N20 is a 45N20 with more current capability, i thought anyway...

19th February 2010, 03:19 AM	#5
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	i used 42N20s in here before. they worked. but i only have 1 of those left, and i need 4. so i guess its off to digikey.

19th February 2010, 03:30 AM	#7
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	well add the 52N20s hehe.

19th February 2010, 03:34 PM	#8
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	digikey doenst have the 3415s.

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