My less than a year old kenwood cd player (forget the exact model number, maybe 6xxx) has a major problem. I'll start at the beginning.
Ever since i've had it in this camaro it has a tendency to cut out (not distort, actually stop making sound for a second.) at high volume with powerful music. Anywhere over 30 while playing ministry, etc and it cuts out when too much sound is going on. I lived with it though, prolly better for my ears. Of note, it doens't have this problem with less powerful music, you can crank the beatles to 35 and it stays clean and doesn't cut out.
Anyhow, just yesterday while jamming at the just below cut out level, it started to distort. Gradually got worse. Turned it down and let it rest then turned it back up and it was OK. Then it started again, and even got so bad that the volume got noticeably lower. Now this makes sense, at high temperatures the amps are losing effectiveness and aren't working right (of course this doesn't bode well for summertime if it overheats in the 30s)
So, i'm thinking to myself how i'll just be getting an amp since it just seems that the internal amps are dying. I was planning on getting an amp to drive the rears and a sub anyway. So i decide to see if it doens't have the overheating problem with only 2 sets of speakers running, so i set the fader to full front. I crank it way up, and it starts distorting (amp, not speakers btw) then cuts out, then completely dies. No sound. So it turn it down for a few seconds and turn it back up (also reset fader to normal), still nothing. So i turn it off and enjoy the road.
A little while later i turn it back on and proceed to limit myself to 26, as even 28 was distorting earlier, and i want to make it home with at least some music.

So my question is, what the hell do i do. I hate to have to get amps to drive all my speakers (btw, the pre-amps should still work if the maps are dead, right...and what is the likelihood that the problem is in the pre-amp processing.) I know you'll balk at this, but wouldn't a cheap amp be better than nothing in this situation. And what are the odds i could crack this baby open and fix it. How hard would it be to get schematics for it? I am a computer engineer doing ASIC design, so i'd like to believe i can diagnose/fix it, even though amplifier design is the reason i hate EE. What intrigues me is that i was able to cause distortion and cutting out and the overheat safety together. It almost makes me wonder if that circuit isn't malfunctioning at high power levels and causing the cut outs, and possibly partially limiting voltage during over high heat times, causing the distortion.

Any ideas...ed

------------------
Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

It seems like you have an internal amplifier built in the head unit that is defective (susceptible to heat). If it is still under warranty and you have the receipt, then contact a Kenwood service center and you should get it fixed with no problems. If you have to pay for repairs, you can bet it will cost you at least $100 unless you have buddies in the electronics repair business.

Getting a true schematic for the unit is an unlikely option since repair shops pay good money to the manufacturers so they can have them. You will be very lucky if you can buy this anywhere let alone get it for free.

Whether or not the internal amps are used to provide output power to the pre-out jacks is unknown. In any event you should consider buying a separate amp. You can get decent amps for about $200 (see my sig) and you will definitely enjoy the benefits.

Hope my .02 helps.

------------------
92 Camaro RS LO3, 5-spd, T-tops
Performance:
SLP 1 3/4" Headers (Coated by Paul Barry Motorsports), Flowmaster Catback Exhaust, Fastchip Performance PROM, Centerforce Dual Friction Clutch, Xact 8mm wires, Open Air Element w/K&N Filter, Z28 Grille w/aftmkt fog lamps
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, Edelbrock performer intake

 

hi ed, u helped me tremendously with my carb, perhaps i may be able to help you here.

if your deck simply cuts out at high volumes then the culprit is the internal amplifier. decks that come with internal power (i.e 35watts*4) are not very well built, its really hard to cram all that stuff into a casing 8*6 inches or sumthin. thats why the decks i buy have no internal amp, i run my speakers off external amps. if the deck is old, what do u have to lose my crackin it open and lookin at the internal parts. since u dont have a warrenty, might as well. it wouldnt be worth sending it back to be repaired if u dont have warrenty. the preamps should work even tho the amp doesnt.

my advice would be to purchase a cheap amp (like 100-200 bucks) to run your speakers. ebay has a good selection of RF or what ever amp suits u best. depending on the # of speakers u have, a 2 channel should be fine. i have a 2 channel RF amp running 8 speakers.

good luck,

daniel

 

I just bought a Kenwood 2 channel amp and the instuctions say that the amp has protection devices that automatically trigger the amp to shut down or cut off for a split second if the amp detects any distortion or high voltages. While I was testing the amp, I turned it up until it was pretty loud and I noticed that it did lower and cut off for a brief moment when the music sounded distorted. I matched the input gain on the amp to match the ouput of my pioneer receiver and everything sounded good even at high levels. I'm sure even though I have a Kenwood amp your Kenwood receiver might still have the same protection circuitry. It sounds like you're over powering your speakers. Are you using any crossovers?

------------------
305 tbi, 5spd, Slp Y-pipe, Random tech Cat, Flowmaster crossflow, Ultimate tbi mods, Edelbrock open element with 3" K&N, Taylor Spiro Pro wires, Redline water wetter, 180* thermostat.