Issue:
I've got a car audio amplifier (hope this is in the right section) Kicker ZX2500.1 (the older model), that I recently tried running. The amp turns on and power light stays green (red indicates protection) but there was no sound out. My assumption from a past install is that the audio wires crossed while the amp was running. So as of now no sound output is my problem. Also I'm very willing to learn and am interested in doing this fix myself, but my current knowledge is limited hope what I'm asking makes sense.
What I observed and have done so far:
I have opened the amp up and noticed mosfet transistors (IRF3205) that hug the side rails were blown, 10 on either side, a total of 20, 18 of which showed physical damage. I have removed the 18 that showed physical damage and desoldered the areas as well.
There was also a diode in between the speaker outputs on the board that appeared to be darkened in the middle, although no bubbling was observed. I ohmed out the diode and was getting 2.149 k steady.
My questions:
1. The transistors were all labeled IRF3205, although some had 5P 6N and others had 2V 7V written below the IRF3205 on the transistor itself. As far as I'm aware these numbers do not indicate a difference in transistors they are simply a lot assembly code, or are they in some way internally different?
2. If these transistors are all the same is there any downside as to where I purchase new transistors, there are some available right now as a lot of 20 on amazon I was considering.
3. The two transistors that did not show any physical damage, is there any way to check them while still attached to the board, prior to removing the other transistors I had ohmed in between the legs and was getting 4.2 steady on 2 of the 3 configurations between metering between the 3 legs. I now have continuity between all 3 legs and there is no ohm reading, is this because I have removed the other transistors? Or are these possibly bad as well regardless of physical appearance and should be changed out at this time? Will it damage anything to leave these 2 in if they are damaged?
4. The diode which is shown has a steady reading of 2.149 k ohms, should I consider changing this as well due to the darkened marking in the center of the diode or would I be getting a much different reading if this diode were bad?
5. The tape or heat barrier that set inside the amplifier and on the rails that sat against the transistors was burnt, do I need to purchase a new barrier of heat sink tape or is there a way of cleaning what I've got now. If I need to purchase new which heat sink tape or material will I need, keeping in mind that the material on the removable rails was thicker than the material inside the amp.
6. I know without seeing the board and metering things out (which I can do just not sure where), where else should I be checking. I'm fixing what's obvious and seen to have been damaged but where else should I be looking for issues on the board?
I have also read in another thread that OpAmps (JRC 2068) were the cause of no sound, should I be testing anything else on the board or replace the blown fets and go from there?
Here are a few shots of the diode in question
Here you can see the blown mosfets under the clamping system
The thinner heat tape on the amp
The thicker material on the rail
What would I need to purchase to replace these materials?
I've got a car audio amplifier (hope this is in the right section) Kicker ZX2500.1 (the older model), that I recently tried running. The amp turns on and power light stays green (red indicates protection) but there was no sound out. My assumption from a past install is that the audio wires crossed while the amp was running. So as of now no sound output is my problem. Also I'm very willing to learn and am interested in doing this fix myself, but my current knowledge is limited hope what I'm asking makes sense.
What I observed and have done so far:
I have opened the amp up and noticed mosfet transistors (IRF3205) that hug the side rails were blown, 10 on either side, a total of 20, 18 of which showed physical damage. I have removed the 18 that showed physical damage and desoldered the areas as well.
There was also a diode in between the speaker outputs on the board that appeared to be darkened in the middle, although no bubbling was observed. I ohmed out the diode and was getting 2.149 k steady.
My questions:
1. The transistors were all labeled IRF3205, although some had 5P 6N and others had 2V 7V written below the IRF3205 on the transistor itself. As far as I'm aware these numbers do not indicate a difference in transistors they are simply a lot assembly code, or are they in some way internally different?
2. If these transistors are all the same is there any downside as to where I purchase new transistors, there are some available right now as a lot of 20 on amazon I was considering.
3. The two transistors that did not show any physical damage, is there any way to check them while still attached to the board, prior to removing the other transistors I had ohmed in between the legs and was getting 4.2 steady on 2 of the 3 configurations between metering between the 3 legs. I now have continuity between all 3 legs and there is no ohm reading, is this because I have removed the other transistors? Or are these possibly bad as well regardless of physical appearance and should be changed out at this time? Will it damage anything to leave these 2 in if they are damaged?
4. The diode which is shown has a steady reading of 2.149 k ohms, should I consider changing this as well due to the darkened marking in the center of the diode or would I be getting a much different reading if this diode were bad?
5. The tape or heat barrier that set inside the amplifier and on the rails that sat against the transistors was burnt, do I need to purchase a new barrier of heat sink tape or is there a way of cleaning what I've got now. If I need to purchase new which heat sink tape or material will I need, keeping in mind that the material on the removable rails was thicker than the material inside the amp.
6. I know without seeing the board and metering things out (which I can do just not sure where), where else should I be checking. I'm fixing what's obvious and seen to have been damaged but where else should I be looking for issues on the board?
I have also read in another thread that OpAmps (JRC 2068) were the cause of no sound, should I be testing anything else on the board or replace the blown fets and go from there?
Here are a few shots of the diode in question
Here you can see the blown mosfets under the clamping system
The thinner heat tape on the amp
The thicker material on the rail
What would I need to purchase to replace these materials?
grrr... one of these days I'll learn to copy my posts to the clipboard before clicking the send button...
Your assumptions on the FETs sound correct. You could look for the manufacturer's numbering/labeling scheme on their website.
Replace all the output devices, even the ones that show no external stress.
It shouldn't matter much where you get replacements. I haven't had big problems buying silicon online, but reading stories here and the coincidence(?) of a lot of the same number used in the amp does cause me a little hesitation. Know thy seller.🙂
If the originals were insulated from the heatsink, insulate the replacements. Use whatever works; it doesn't have to be a tape.
The component you're calling a diode is R506, a resistor.
When things shorted out, the current surge flowed through the output FETs and other active and passive components in the circuit. You'll need to check the parts in those areas; some may have internal damage but look fine. The frontend circuitry probably survived unscathed.
Your assumptions on the FETs sound correct. You could look for the manufacturer's numbering/labeling scheme on their website.
Replace all the output devices, even the ones that show no external stress.
It shouldn't matter much where you get replacements. I haven't had big problems buying silicon online, but reading stories here and the coincidence(?) of a lot of the same number used in the amp does cause me a little hesitation. Know thy seller.🙂
If the originals were insulated from the heatsink, insulate the replacements. Use whatever works; it doesn't have to be a tape.
The component you're calling a diode is R506, a resistor.
When things shorted out, the current surge flowed through the output FETs and other active and passive components in the circuit. You'll need to check the parts in those areas; some may have internal damage but look fine. The frontend circuitry probably survived unscathed.
Thanks sofaspud, any ideas to use as the heat barriers on the rails? I think I can clean the existing tape with some acetone but there are gouges in the thicker material where the burns occurred. Also any key active/passive components I might want to check? Not sure where to start as I don't have a schematic and my current electrical understanding is minimal.
And does the R506 resistor need replacing, considering I got a reading of 2.149k ohms?
And does the R506 resistor need replacing, considering I got a reading of 2.149k ohms?
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I'm not sure what the thicker material is, but the gouges do need to be fixed or accommodated somehow. Maybe they could just be filled with a little extra heat sink compound when the replacements are fitted. Or maybe a mica insulator needs to be used as a patch.
The key components would include things like resistors on the collectors and emitters of the power transistors. Without a schematic or familiarity with the circuit it's hard for me to say exactly. You should also check the PCB traces. There may be some that show visible signs of high current - darkened color or bubbling. The good thing is those will lead you to other components to check.
R506 could well be a 2% 2.2k ohm resistor. That's what it appears to be in the photo. I would replace it anyway, just because it's obviously physically damaged. It might measure fine now, but next time it warms up the resistance may drift way out of tolerance.
The lack of docs and training means your job won't be very easy. But it is possible. Like a lot of DIY projects, the start and the finish is often the most difficult part.
The key components would include things like resistors on the collectors and emitters of the power transistors. Without a schematic or familiarity with the circuit it's hard for me to say exactly. You should also check the PCB traces. There may be some that show visible signs of high current - darkened color or bubbling. The good thing is those will lead you to other components to check.
R506 could well be a 2% 2.2k ohm resistor. That's what it appears to be in the photo. I would replace it anyway, just because it's obviously physically damaged. It might measure fine now, but next time it warms up the resistance may drift way out of tolerance.
The lack of docs and training means your job won't be very easy. But it is possible. Like a lot of DIY projects, the start and the finish is often the most difficult part.
The fets have arrived but prior to putting them in I wanted to check a variety of things, all of the gate resistors physically appear to be ok, the lowest reading 147 ohms and the highest at 151 ohms. Also the R506 resistor pictured earlier, how would I check the wattage on this so I can order a replacement?
I did notice something else on the other side of the board, it's on a small board that mounts vertically to the amp labeled "Sub 2". The first being a smaller capacitor to the left in the first photo, it appears to have the outer jacket damaged. I checked it and the ohms appeared to match that of a capacitor on a similar board nearby. The second thing being a hardened clear substance on the board.
I did notice something else on the other side of the board, it's on a small board that mounts vertically to the amp labeled "Sub 2". The first being a smaller capacitor to the left in the first photo, it appears to have the outer jacket damaged. I checked it and the ohms appeared to match that of a capacitor on a similar board nearby. The second thing being a hardened clear substance on the board.
I hate to bombard this thread with questions but 18 of the 20 resistors I ordered have a date code of P230D, and lot code of A8KZ. 2 of the 20 have a date code of P210P, and lot code of 5WRG. My question is, will I be alright with the 10 matching on one side of the amp and the 8 plus the 2 with the different code on the other. I had seen an older post where its said that having at least one entire side matching is better than having all mismatched. Any thoughts, on this or anything above?
Do not ever mix date codes when using devices in parallel.
If you do the amp may work for a while but eventually it will fail again.
If you want it to be reliable ALL the date codes on the power supply FETS must match!!
Same with the drive transistors too!!
Same with the outputs!!
If you do the amp may work for a while but eventually it will fail again.
If you want it to be reliable ALL the date codes on the power supply FETS must match!!
Same with the drive transistors too!!
Same with the outputs!!
Sorry about not updating, I did get new FETs with all matching codes will be getting them on the board and go from there. Other than a resistor fixed I will need to run more testing on the amp to find out where problems lie before powering the amp up. I will update after I get these components in.
Make sure you put a 10-15 amp fuse on the B+ line when you go to test it out. You'd hate to smoke 20 fets you just put in. It may need a bit bigger fuse considering its size. I'd let the caps charge up before trying to apply the remote wire also. R= Resistor, D= Diode, C= capacitor... When you see a number with a letter beside it the letter identifies the component type. R506 = Resistor 506, change that one.. good luck
I have the same problem
I have a kicker zx2500.1 with the same problem and I'm new to forums did Steven manage to get it working and what all did you have to change ?
I have a kicker zx2500.1 with the same problem and I'm new to forums did Steven manage to get it working and what all did you have to change ?
very difficult amp to attempt as a 1st repair i have just completed the same amp not so long ago, took some time to get it going
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