Looking for a bit of information. I found one of these resistors on this Kicker ZX750.1 to be completely open. They appear to be 3.3K Ohm 5% and look to be 1 Watt.
I cannot seem to source these. Mouser and DigiKey seem to only carry up to 1/2W in this value. Are these truly 1 Watt? And they don't appear to be flameproof, but I could be wrong there as well. Seems strange that it would fail so badly and not show any signs other than being slightly darkened like the rest of them are.
The other strange thing is I have not found anything else wrong other than this failed resistor. The amp actually works fine and puts out full un-distorted power. I got 782W RMS Dynamic out of this amplifier before clipping.
The issue is it runs extremely hot, even with no signal or load. one bank of output FETS gets very very hot very quickly as soon as it's powered up.
I cannot seem to source these. Mouser and DigiKey seem to only carry up to 1/2W in this value. Are these truly 1 Watt? And they don't appear to be flameproof, but I could be wrong there as well. Seems strange that it would fail so badly and not show any signs other than being slightly darkened like the rest of them are.
The other strange thing is I have not found anything else wrong other than this failed resistor. The amp actually works fine and puts out full un-distorted power. I got 782W RMS Dynamic out of this amplifier before clipping.
The issue is it runs extremely hot, even with no signal or load. one bank of output FETS gets very very hot very quickly as soon as it's powered up.
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If this resistor is open, more than likely the BZG03C12 zener diode tied in series is leaky, The 12 volt zener sets the voltage for one of the drive circuits. If the voltage is low the amp will work but not efficienlly.
What is the locator number for the resistor in question. This is a 3.3K 2watt resistor, btw, and you should be able to source them at Mouser or Digikey, maybe Allied. If not Radio Shack will do.
The amp appears to be a 2008 or later model year, please send a pic of the entire board and a pic of the preamp board both top and bottom. I worked for Kicker and can better advice if I no what rev the amp is.
What is the locator number for the resistor in question. This is a 3.3K 2watt resistor, btw, and you should be able to source them at Mouser or Digikey, maybe Allied. If not Radio Shack will do.
The amp appears to be a 2008 or later model year, please send a pic of the entire board and a pic of the preamp board both top and bottom. I worked for Kicker and can better advice if I no what rev the amp is.
Here is a pic of the board.
Honestly it's hard to tell what location number this is as there are quite a few "Rxxx" assignments near that location. R198 It appears. Its the one on the right in the picture. You can see where I removed the left one as well, its was just to compare them out of the board to make sure I wasnt getting false readings or something.
Which Zener(s) should I be questioning? The 4 near that location in the picture all read correctly.
Honestly it's hard to tell what location number this is as there are quite a few "Rxxx" assignments near that location. R198 It appears. Its the one on the right in the picture. You can see where I removed the left one as well, its was just to compare them out of the board to make sure I wasnt getting false readings or something.
Which Zener(s) should I be questioning? The 4 near that location in the picture all read correctly.
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Radioshack has had pretty decent parts, considering how few they must sell, like Alps stereo volume controls for $4, etc.
Give them a chance. You can use two in parallel or series if necessary.
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This may be due to a leaky zener, which would not show up on an ohmmeter or diode check. Hard to say other wise, defective resistor or failure over time, the resistor needs to dissapate a lot of heat and, although its rare I've seen the resistor open up on occasion.There may be other issues which will may need exploring if the zener and resistor don't fix the problem.
Search results for "BZG03C12" - Allied Electronics
Here is a link to source the zener diode.
The 12v zener sets the voltage for one of four drive circuits to the outputs, in this case the drive is for the bank of IRF9640's on one side-Q109,110,111.
For whatever reason R198 opening up or D107 becoming leaky, it would leave less of a voltage drop across D107, which means that bank of outputs would have little or know drive. I've seen 5 or 6 volts on these zener's, which will allow the amp to make power, although my guess is its not very clean and inefficient.
So I swapped out the 3.3K resistors, and have not swapped out the diodes. All of the excessive current went away, I am getting a clean square wave to the FETs, and they are not getting hot at all anymore. Should I still change the diodes?? Or should I just leave it the way it is?
Seems to be fine now.
Seems to be fine now.
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