Rockford Fosgate Power 650 - Page 3

seankane · 16th January 2013, 04:17 AM

I replaced all the outputs and drivers in that channel. I powered the amp and it was drawing 40 amps current. 3 of the IRF540 FETS were getting hot. I removed those 3 and re powered the amp and it powered up fine.

I re-installed them and it powered up and blew the fuses for that channel.

I removed the D41D8 and powered the amp and the 10uf 50v cap next to it exploded. I replaced the cap and the driver and repowered the amp.

The 75 ohm resistor next to the D41D8 instantly smoked. I replaced it and repowered the amp. Then the 75 ohm resistor next to the D40D8 instantly smoked.

I am not sure what is going on here. It is hard to follow the schematic, as there is no silk screen markings on the board.

Some of the fuse holders have 14 vdc going to them when just power and ground are hooked up and some dont, is this right? When the amp is powered they have rail obviously.

I am at a stand still, unsure where to go next. I dont want to keep blowing parts.

seankane · 16th January 2013, 05:46 AM

Please read post #21 first.

If I leave the fuses out for that channel the amp powers fine. Whatever fuse I put in for that channel it burns the 75 ohm resistor. 1 fuse burns the 75 ohm resistor by the D40D8 and the other fuse burns the 75 ohm resistor by the D41D8.

Any ideas?

Perry Babin · 16th January 2013, 09:07 AM

If you power it up through a current limiter, does that stop the resistors from burning long enough to measure the DC voltage between the bases of the D40 and D41?

Does it help if you set the bias pot fully counter-clockwise?

seankane · 16th January 2013, 05:46 PM

Quote:

Originally Posted by Perry Babin

If you power it up through a current limiter, does that stop the resistors from burning long enough to measure the DC voltage between the bases of the D40 and D41?

Does it help if you set the bias pot fully counter-clockwise?

The bias pot is fully counter clock wise.

You want me to measure across the bases of the D40 and D41? Red probe on one base and black probe on the other base?

seankane · 16th January 2013, 06:55 PM

The amp will not power up through a current limiter with the fuses installed. If both fuses are in with a current limiter just hooking up power and ground makes the amp draw current and when the remote is applied it will not power.

If I remove the 2 fuses for that channel the amp will power up, but I dont think I can get an accurate reading across the bases of the 2 transistors you need without the fuses installed can I?

Something in that channel has to be shorted or something???

Perry Babin · 16th January 2013, 06:59 PM

If you can't do that, check each of the 4 diodes in the string connected to the output of the op-amp. Do any read more than about 0.6v (no power applied, meter on diode-check)?

seankane · 16th January 2013, 07:02 PM

All 4 read about 0.565v

Perry Babin · 16th January 2013, 08:02 PM

With the bias pot fully counter-clockwise, what resistance do you read between the bases of the D40 and D41?

seankane · 17th January 2013, 04:23 AM

0.450K ohms

Perry Babin · 17th January 2013, 09:45 AM

Solder a jumper between the bases of the D40 and D41. Does that allow the amp to power up through the limiter?

If so, does that channel produce audio?

16th January 2013, 05:46 AM	#22
seankane diyAudio Member Join Date: May 2010 Location: Washington State	Please read post #21 first. If I leave the fuses out for that channel the amp powers fine. Whatever fuse I put in for that channel it burns the 75 ohm resistor. 1 fuse burns the 75 ohm resistor by the D40D8 and the other fuse burns the 75 ohm resistor by the D41D8. Any ideas? __________________ Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch

16th January 2013, 09:07 AM	#23
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you power it up through a current limiter, does that stop the resistors from burning long enough to measure the DC voltage between the bases of the D40 and D41? Does it help if you set the bias pot fully counter-clockwise? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

16th January 2013, 06:55 PM	#25
seankane diyAudio Member Join Date: May 2010 Location: Washington State	The amp will not power up through a current limiter with the fuses installed. If both fuses are in with a current limiter just hooking up power and ground makes the amp draw current and when the remote is applied it will not power. If I remove the 2 fuses for that channel the amp will power up, but I dont think I can get an accurate reading across the bases of the 2 transistors you need without the fuses installed can I? Something in that channel has to be shorted or something??? __________________ Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch

16th January 2013, 06:59 PM	#26
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you can't do that, check each of the 4 diodes in the string connected to the output of the op-amp. Do any read more than about 0.6v (no power applied, meter on diode-check)? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

16th January 2013, 07:02 PM	#27
seankane diyAudio Member Join Date: May 2010 Location: Washington State	All 4 read about 0.565v __________________ Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

16th January 2013, 04:17 AM	#21
seankane diyAudio Member Join Date: May 2010 Location: Washington State	I replaced all the outputs and drivers in that channel. I powered the amp and it was drawing 40 amps current. 3 of the IRF540 FETS were getting hot. I removed those 3 and re powered the amp and it powered up fine. I re-installed them and it powered up and blew the fuses for that channel. I removed the D41D8 and powered the amp and the 10uf 50v cap next to it exploded. I replaced the cap and the driver and repowered the amp. The 75 ohm resistor next to the D41D8 instantly smoked. I replaced it and repowered the amp. Then the 75 ohm resistor next to the D40D8 instantly smoked. I am not sure what is going on here. It is hard to follow the schematic, as there is no silk screen markings on the board. Some of the fuse holders have 14 vdc going to them when just power and ground are hooked up and some dont, is this right? When the amp is powered they have rail obviously. I am at a stand still, unsure where to go next. I dont want to keep blowing parts. __________________ Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch

16th January 2013, 08:02 PM	#28
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	With the bias pot fully counter-clockwise, what resistance do you read between the bases of the D40 and D41? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

17th January 2013, 04:23 AM	#29
seankane diyAudio Member Join Date: May 2010 Location: Washington State	0.450K ohms __________________ Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch

17th January 2013, 09:45 AM	#30
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Solder a jumper between the bases of the D40 and D41. Does that allow the amp to power up through the limiter? If so, does that channel produce audio? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Rockford Fosgate Power 650 Mosfet "rejuvification"	pgerry	Car Audio	16	20th October 2012 02:25 PM
Rockford Power 650 Mosfet	seankane	Car Audio	16	7th September 2011 07:17 PM
Rockford Fosgate Power 20001 bd amplifier power rating??	pachoorion	Car Audio	8	8th May 2011 10:49 PM
rockford fosgate power 650 mosfet	mike49504	Car Audio	43	24th March 2011 10:21 PM
Help with Rockford Fosgate Power 650	shawnk	Car Audio	31	14th July 2010 08:11 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read