stereo help

[jordano]

having a bitg of problem with my stereo guys, when i turn it up it just cuts out and turns off but then comes straight back on but does it again if i dont turn it down, ne ideas. im running 4 speakers off the head unit and a single amp running a sub. i have checked the ground for the sub and it is fine as i was told this may be the problem

[kam-325i]

How is the Amp connected to the Head unit, Via a Pre-amp output ?

[TOURINGDADDY]

u need to check the earth on the amp that will b ur first port of call
make sure its a good earth

[jordano]

yeah the head unit has 3 pre outs and iam running the amp off the sub one. checked the earth on the amp and belive it to be ok but to be sure i disconnected the remote turn on thus eliminating the amp from the system and it its still cutting out?

[Incitatus]

Sounds very much like the protection circuit in the head unit's amp is cutting in. Check the wires arn't shorting out to any of the speakers and if possible check the resistance of the speakers with a multimeter. Try disconnecting each speaker in turn to see if it still cuts out with it disconnected. Nothing on the pre-amp stage would cause the head unit to cut out so you can be sure that the sub's not responsible.

[jordano]

dont wnna sound dumb but how do i check if the wires are shorting out to the speakers and also i do have a multimeter but not too clued up on it,how do i check the resistasnce

[Incitatus]

Set the multimeter to the Ohms setting, and touch the two probes together to test, it should show 0 when they touch and something like OC (open circuit) or a very high reading when they're not.

Disconnect the ISO connector on the back of the head unit with the eight wires for the four speakers, and check the resistance between each pair of wires going to each speaker (you should be able to make a connection through the ISO plug with the probes). Car speakers have a resistance of four Ohms (compared to a domestic speakers eight) If you have a reading significantly less than four you've found the problem. I think it's best to compare the results of matched speakers, ie if the front two speakers are different to the rear, compare them to each other and then to the rears to see if and how the results differ.

Of course the less scientific way to have a play is to use the balance and fader to power one speaker at a time, front left by itself for example. Try driving each speaker to the volume level it normally cuts out on, and see what results.

If when running the four speakers you notice the display and buttons dimming when there's a bit of bass going on, it could be down to a problem with the power supply to the head unit itself.

Or the head unit could be knackered.... Or I could be talking rubbish

[jordano]

yeah there is dimming doing on with the head unit,also i have found out that it works fine with the stereo more or less pulled complete out of the cage?gonnna have a look at the speakers like you mentioned today as i didnt get time yesterday through helping my dad build,cheers for all ur help

[Fushion_Julz]

Ahh...if the dash panel lights dim when you turn the volume up, the likely problem is that the amp you fitted has a current draw too large for the battery. I assume that the amplifier +ve is wired direct to the battery and the -ve either goes back to the battery or that the measured resistance between the ground point and the battery -ve terminal is less than 0.05ohms.

Also check your speakers are wired correctly using new wires to the speakers running off the amp, at least. The standard loom wires are useless for this..

You may need to fit either a secondary leisure battery (and split charging) or a large capacitor (available at Maplins and most car hi-fi shops)...

Or turn it down

[jordano]

like i sed earlier im running 4 speakers off the head unit and a sub from the sub output,its a 1000w alpine sub but i think the amp is only 400w. As for the lights dimming i was only referring to the lights on the stereo not the ones on the dash? Ive just noticed that where the ground lead comes out of the plug thing on the back off the stereo the rubber/plastic insulation cover has come away from the wire,not totally but there is bare wire showing,could this be the problem,i cant see that it could touch anything else like,its right at the end of the wire so will be difficult to cover.

[Incitatus]

If as you said before you've disconnected the remote turn on for the sub amp, and still have a problem, it can't be due to current drain from the sub. You shouldn't have any trouble running the head unit and sub anyway.

I think if it works ok when the head unit is removed from the dash a bit, you must be causing a problem when the wires get shoved in behind the head unit when it's sitting in place. Check all the speaker wires are ok and are not making a short (like on that bare bit of ground wire).

[jordano]

still didnt get chance to have a look today,keep putting it off,but its gone all together now so its first thing im doing in the morning as i cant stand not having ne tunes,im gonna take it all out and start again so i will let u know how it goes,probably of pulled all my hair out but at least i shud have some music

[jordano]

like i said it went all together yesterday,so i pulled the head unit out today and the glass fuse had gone on the permanent live, it was only like a 2.5 amp so ichanged that for a 25amp covered the bit of wire showing on the ground wire and changed put a 25amp glass fuse on the turned on power lead and all seems tro be sorted,thanks for all the help guys much appreciated