QuestionQUESTION: Hi, I've got a Kenwood KAC-929 that powers on and the fan will kick on but it won't put out any sound. Could it maybe the output transistors or any type of RCA connection? And could you estimate how much this might cost to be repaired? Thank you for your time!
ANSWER: Sounds like a troubleshooting mission. You must determine if the problem you are facing is internal or external. By that I mean is it in the wiring or grounding or the feed signal from the head unit (that is external to the amp) or is it a failure inside the amplifier itself (internal).
An open or defective cable going to the inputs will cause that, of course, but if you have stereo signals going in only one channel would be out. A bed head unit that is not sending signal could the cause, as well!
An easy way to check this is to use a portable cd player or mp3 player and feed into the amplifier directly (you may have to add a conversion plug or adapter to go from the output of the portable device to rca). You can check one channel at a time or both if you have stereo.
Of course you must make sure the speaker connections are good and that the speakers are working (stranger things have happened; I know of cases where both speakers were blown and the user did not realize it!)
Check the ground connection on the amp and the metal to metal connection of that ground to the chassis of the car - it may be good for the fan but goes open when the speakers are connected.
Once you have determined the problem is "internal" then the amp must be serviced and it may be the output transistors blown, or more likely the heat link fuse inside the set is gone. It is also possible the amp has merely locked up into the protection mode. You can release it by pulling the 12v lines off at the amp for a few minutes and then re-connecting.
Depending on what the problem is repair costs would range widely but should not be all that expensive.
I have given you lots to do, so let me know how it goes and if you need more help.
c
---------- FOLLOW-UP ----------
QUESTION: Ok. I've hooked it up where i have 2 other amps set up and they work great. But it just comes on, fans comes on and the light. I've hooked 4 different subs up to it that i no work fine. I had my uncle look at it because he deals with Car audio and Loudspeakers. He says one of the capacitors in it are loose and on the board there are like 3 small scratches going threw what are basically electric lines in the amp. It's basically like its not receiving any RCA input. All the fuses are good also. By the way, thank u for such a quick reply.
AnswerSounds like you are heading in the right direction. If some of the circuit foils are lifted or broken that could be the entire problem. The loose cap could be what has started the deterioration of the foils.
A tech will put on a signal tracer and find out how far the signal is getting; by knowing that the location of the problem is determined. Then, knowing the section that is losing signal can lead to finding the faulty parts or open circuits. It may involve replacing or repairing the cap and reconnecting the open foils - or such repairs. But, it will require one who has the learnt skill and know - how to trace down the failure point and know what to do to restore its working condition. Audio techs do this kind of thing all day long and it is not difficult - but must be done carfully and with a trained person who knows about these things.
Looks like you are off to the repair tech/expert. Good Luck,
c
