I recently picked up kx2500.1 by kicker, right out of the gate the power supply needs a rebuild, Ive read the other posts about these amps one success story and one just faded away right before the good stuff.
Theres 20 FETS that ill order there also is a vertical board that has a burned capacitor not sure if that would have anything to do with it, is this possibly the driver board?
any info anyone could provide would be greatly appreciated.
Thanks
Theres 20 FETS that ill order there also is a vertical board that has a burned capacitor not sure if that would have anything to do with it, is this possibly the driver board?
any info anyone could provide would be greatly appreciated.
Thanks
Im not sure as i have not dealt with that amplifier very much but contact db-r from any of the car audio message boards and hes a good guy and can def help you out. Hes the leading amp repair guy in the car audio world right now.
caraudio.com
diymobileaudio.com
caraudioclassifieds.org
just to name a few.
or message him at his website db-relectronics.com or something like that.
Hope i helped.
caraudio.com
diymobileaudio.com
caraudioclassifieds.org
just to name a few.
or message him at his website db-relectronics.com or something like that.
Hope i helped.
Ok replaced all the fets, now cycling in and out of protect mode, so I start metering outputs, found a IRF9640 shorted and a FBJ1N200.
In this amp the are 4 groups of 3 IRF31N20D's and 5 IRF9640's
Both bad components were in the same group.
Should I still change all 4 groups at the same time?
Or can I change the bad group?
Anyone know if I can use IRF640's in place of the FBJ's?
In this amp the are 4 groups of 3 IRF31N20D's and 5 IRF9640's
Both bad components were in the same group.
Should I still change all 4 groups at the same time?
Or can I change the bad group?
Anyone know if I can use IRF640's in place of the FBJ's?
Last edited:
Maybe too late, but you can replace the IRF31N20D with IRF640. You should replace all 12 mosfets,but at the very least change in 3's. When I work on this amp, I will change all 32 mosfets, 9640's and 640's. And before I install the outputs there are a few voltage a waveform checks to do. Make sure you have a good triangle wave (80khz?) coming from Pin 4 of LM361 IC and 50% duty cycles from pins 9 and 11. There are 4- 330 ohm 3 or 5 watt resistors (depending on model year-newer amps are higher wattage resistors).Check the dc voltage from power GND to resistors-should read 40 volts on the common node of 2 resistors and 51 to 54 volts on the output driver side(sub1 and sub2 boards-each resistor ties to a 12 volt zener on sub boards) and while outputs are still removed and the amp is powered off check each output bank with an ohmmeter. The 640 banks should read 33 kohms(3-100kohms in parallel) and the 9640 banks 20kohm(5-100kohms in parallel), the gate resistors should all read 10 ohms and connected into their respective mosfet gates.The voltage drop across each bank of 640's should be about 4 volts and 9640's 4.5 volts. If all this checks out you should be good to go. replace outputs and recheck voltage drops. The older boards tend to be unstable and outside of chassis will idle high (10-15 amps) and you have to be careful not to short one of the power supply mosfets. If one does short cut it out and finish checking amp. After checking replace shorted mosfets and return to chassis-you could do all this in the chassis but taking it it and out might get old!
Also, carefully examine the four output inductors, particularly the inductor associated with the shorted outputs, look for delaminated windings and hot spots. you may have to remove the inductor and check the underside. Pay close attention to the sleeves on the leads of inductors and make sure they are not perforated or they may be shorting the windings causing shorted outputs,add any addition sleeving to the leads if necessary.We use a rubberized cloth material that slips over existing sleeves,not sure where to purchase.
The IFR640 is the part used in most Kicker amps, and is the part Kicker put in place of the IRFB31N20D midway through the 06 model year. I believe the 31N20D was hard to source or become unavailable and Kicker decided to use the same IRF9640/IRFF640 match up they used with the IX405D and later the KX and ZX line. The 640's tend to short out more often than the 9640's not sure why, but I suspect they are the weak link,because of the smaller number. The 05 & 06 are notoriously unstable outside the chassis(not clamped to a heatsink) and will get hot quickly, however the 08,10 and 11 are much more stable and I can safely run them outside the chassis for extended periods of time.of course with out a load. You may be right,there may be a better mosfet/mosfet combination. and if you know what it is I'd be interested to hear of it,or if a good source for FB31N20D is around that would be recommended. I work for Kicker in the repair department for the past 13 years,and I've spent a lot of hours working on this amp among others, but I'm always open to improvements. My passion is teaching people how to troubleshoot and repair electronics,which I do a fair amount on the job with engineering students who work for us while working towards a degree. I Joined these forums to offer a hand and learn from others,especially techs who have a wider range of experience working with car amplifiers. I am forever trying to hone my craft and find it challenging to troubleshoot an amp I don't have on hand!
Last edited:
I know that the 640s were used in some of the amps but from my experience and from helping those trying the 640s as subs for amps that originally had the 31N20s, the 640s overheated quickly.
I buy the 31N20s from either digikey or arrow and have never had a problem with them. Most of the ones on ebay seem to be counterfeits. I've had people buy them from ebay and had problems with them failing and overheating. They purchased them from digikey and that solved their problem (with no other changes).
If you're going to try to help someone vie email or forum, you have to do it like you would write software. You have to be very specific about what you want and how they have to perform the tests. For some, you have to tell them precisely how to set their meters and which points to place the red and black probes on.
You have one advantage over everyone else here, you have access to Kicker technical documents (schematics). That will make it easier for you to help with many problems.
I buy the 31N20s from either digikey or arrow and have never had a problem with them. Most of the ones on ebay seem to be counterfeits. I've had people buy them from ebay and had problems with them failing and overheating. They purchased them from digikey and that solved their problem (with no other changes).
If you're going to try to help someone vie email or forum, you have to do it like you would write software. You have to be very specific about what you want and how they have to perform the tests. For some, you have to tell them precisely how to set their meters and which points to place the red and black probes on.
You have one advantage over everyone else here, you have access to Kicker technical documents (schematics). That will make it easier for you to help with many problems.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.