My kenwood Kac-819 worked perfect for years in my old car. I took it out when I sold my car and now I installed in my new car with my Alpine CDA105 and it won't power up! I took it into Best buy and they bench tested it and it powered for a second but tripped their connection.... I don't understand what could have happened from one car to the next! I took it apart now and it looks clean and everything seems connected and nothing looks blown...
Please help.
Please help.
It may have shorted output transistors.
If it tripped the protection in their power supply, it should have blown the fuses when you installed it. Did it blow the fuses?
If it tripped the protection in their power supply, it should have blown the fuses when you installed it. Did it blow the fuses?
Both fuses are perfectly fine. They both have continuity too! They are both 30amps. Which is what came with the amp when I bought it years ago.
How do I check for shorted output transistors? How much would it cost for me to just replace all 4? Also is it as easy as just unscrewing and then screwing the new ones down tight?
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Have you read the entire basic amp repair page yet? If not, (link in sig file below), do so now.
There's no point in replacing parts if you don't know if they're defective.
There's no point in replacing parts if you don't know if they're defective.
So if the output transistors are shorted or just one of them is, it would stop the whole amp from powering up?
Also nothing personal, but for basic that guide is WAY in depth and overwhelming...
If it will only cost me like $5 for all 4 output transistors then I would do that in a heartbeat!
How Do I Test them?
Also nothing personal, but for basic that guide is WAY in depth and overwhelming...
If it will only cost me like $5 for all 4 output transistors then I would do that in a heartbeat!
How Do I Test them?
The tests are producing conflicting results. I'm assuming that they used a power supply that works well to power up other amps. If that's true, enough current draw to shut it down should be sufficient to blow the fuses.
The outputs for this amp appear to be ~$10 each plus shipping (pacparts and kenwoodparts).
You should not read anything near 0 ohms between the legs of any individual transistor no matter the probe placement on that transistor.
The outputs for this amp appear to be ~$10 each plus shipping (pacparts and kenwoodparts).
You should not read anything near 0 ohms between the legs of any individual transistor no matter the probe placement on that transistor.
So red probe on left leg and put black probe on middle then read and then black on right probe and read?
Do this for all output transistors?
My readings "should not read anything near 0 ohms between the legs of any individual transistor"?
Do this for all output transistors?
My readings "should not read anything near 0 ohms between the legs of any individual transistor"?
Well here is what found doing the ohms tests on all 4 of the output transistors. I had the meter set to 200k on the ohm setting.
The readings that I put 1__._ they are the same as no connection; probes not touching anything or themselves!
The readings that I put 1__._ they are the same as no connection; probes not touching anything or themselves!
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None appear shorted but that's a bit of a guess since you didn't include the units. I'm assuming that all are k ohms. If you would have filled in the other blanks with the meter set to diode check, it would be more definitive.
I have no idea how to do diode. And yes the setting was always on 200k...
So if none were shorted what should I test next?
So if none were shorted what should I test next?
My meter has the symbol that looks like an arrow to the right with a vertical line through it. but it doesn't beep...
For the tests that produced the 1.4 and 1.5 readings, go back and repeat those tests with the meter set to 2000 ohms and with the meter set to diode check.
Those seem OK. The problem is likely elsewhere. reinstall it and confirm that you have proper voltage at the power terminals of the amp.
With your multimeter set to DC volts, the black meter probe on the ground terminal of the amp (not on the point where the ground wire connected to the vehicle) and the head unit on (so the amp will have remote voltage applied), touch the red probe alternately to the B+ and remote terminals of the amp. If the voltage is below ~11 volts on either the B+ or remote line, you need to check the wiring feeding whichever line is too low. If 'both' the B+ and remote turn-on lines are low and your battery is fully charged, you may have a bad ground connection.
With your multimeter set to DC volts, the black meter probe on the ground terminal of the amp (not on the point where the ground wire connected to the vehicle) and the head unit on (so the amp will have remote voltage applied), touch the red probe alternately to the B+ and remote terminals of the amp. If the voltage is below ~11 volts on either the B+ or remote line, you need to check the wiring feeding whichever line is too low. If 'both' the B+ and remote turn-on lines are low and your battery is fully charged, you may have a bad ground connection.
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