why oh why?????

[cxcxcxvcvcvc]

ok as some know i had a problem with my fusion jonah lomu d class amp a few months back, well i sent it to fusion and they repaired it for free outside of its warranty(champs) well today the amp has blown again:cry: when i dropped my son off for school the amp was working fine (subs running) and then all of a sudden the subs just stopped...! i was not even cranking the subs! so as soon as i noticed subs werent running i turned the amp off, and after getting home did a test with my multi, checked all power cables fuses, earths and just like before i cannot see what has cause this to happen:bang::bang: i have a 4 channel amp running of the same power supply and that amp is working fine!
i cannot believe this!!aarrrggghhhh!!!!:ranting::ranting::bang::bang::bang::ranting: for $1500 for this amp when new you would think it would be a hell of alot more stable than this!!!! and i can just bet that fusion wont be fixing it again for free this time round the last time they reapaired it they said that it had blown some resistors? i dont care anymore im getting sick of this pitcure sorry for the rant fellas just had enough....

 

[88GreenVN]

Get it off ya chest there fella.... It does help.:thumbsup:

It may not cost all that much to fix - a few resistors at Dick Smiths & a bit of solder.

 

[cxcxcxvcvcvc]

Get it off ya chest there fella.... It does help.:thumbsup:

It may not cost all that much to fix - a few resistors at Dick Smiths & a bit of solder.

cheers mate!
yeah, well i rang up fusion and told them whats the go , and they said they are going to send out a rep to have a look @ the car to determine whats going on! i said that i would like nothing more than that! the bloke on the phone said, that even though the resistors where replaced last time on the amp, that still the underlying fault in the amp may not have been fixed! so maybe just maybe when the guy from fusion comes out and after looking @ the car (if he can find nothing wrong) then the amp might get fixed for free again! but he wont be out for about a week the guy said as he,s down in sydney @ fusion,s head quarters ect! but at least theres a little light at the end of the tunnel

 

[impulsesv6]

could be worth while popping into a totally indepentant audio shop just to make sure 100% that it isnt caused by install - cos if they want to be sneaky thats what they will blame it on.

then if they do blame it on install just say that ................car audio shop says it aint.

 

[cxcxcxvcvcvc]

could be worth while popping into a totally indepentant audio shop just to make sure 100% that it isnt caused by install - cos if they want to be sneaky thats what they will blame it on.

then if they do blame it on install just say that ................car audio shop says it aint.

yeah i might do that, but ive already pulled the amp! i will be going through the car today with a comb to make sure everything is in order honestly though im not worried about my install, i know i have installed everything the right way and double checked everything, in fact when i got the amp back from fusion i pulled the head deck out of the car, the eq, and ran better wireing to the amp cheked all connections ect because i wanted to be sure and have peace of mind & didnt want this to happen i spose even though you make precautions these things can still happen well its really up to fusion now!

 

[HotVS75]

Where is the earth placed for the amp?

 

[cxcxcxvcvcvc]

Where is the earth placed for the amp?

on the rear wheel arch! i have stripped the paint back to bare metal and put a gold plated earth connection on the rear wheel arch!
i have also tested the amp with a multi @ its inputs and theres plenty of current there!

 

[Joe Peeps]

Sorry to hear about your dramas mate, that must be incredibly frustrating especially when you know your install is up to scratch... Hopefully it turns out ok for you buddy.

Where is the earth placed for the amp?

Where would you recommend in a VS APS? The wheel arch as used here? Baby seat bolt?

 

[cxcxcxvcvcvc]

Sorry to hear about your dramas mate, that must be incredibly frustrating especially when you know your install is up to scratch... Hopefully it turns out ok for you buddy.



Where would you recommend in a VS APS? The wheel arch as used here? Baby seat bolt?

yeah cheers mate! will have to wait another week before this guy comes out, then i will have to wait about another month and a half to get it sent back to fusion to get it reapaired

 

[HotVS75]

Well a VS is a monocoque chassis which means the car has chassis rails which end underneath the front seat and the rest of the shell is supported by sheet metal which is spot welded in certain spots so that it supports the structural integrity of the car but so that if the car were in an accident it will crumble around the cabin minimising damage to its occupants. Well this is the general idea anyway.

Also the main chassis rails are held onto the shell with 4 main bolts. This makes the monocoque chassis a prick of a thing when it comes to earthing.

Has anyone measured the resistance back to the negative of the battery from a Commodore, any commodore VN onwards. You come up with about 7.5 to 8 ohms resistance which is wayyy to high. The return path for an amplifier thru a vehicle chassis should be less than 0.2 of an ohm.

So the best position to earth an amplifier in a VS is under the rear seat or as close to the main chassis rail under the front seat where the sheet metal doubles.

The baby seat bolt, parcel shelf, wheel arch any of that area is not a good earth because it is only supported by spot welds.

Also with Commodores the best way to install an amplifier is to do an earthing kit under the bonnet, upgrade the charge wire to 4 gauge from the alternator, and also run a 0 gauge earth from the negative of the battery to under the front seat secure with a bolt under the front seat where the sheet metal is double, and then run the rest of the 0 gauge to the back where the amplifier is earthed. This reduces the resistance and gives the amplifier an alternate return path for ground should the chassis be weak which in a Commodores case it is.

You will find a lot of Pioneer headunits fail in Commodores where people run amplifiers due to the amplifiers trying to find the closest earth appart from the main earth point and it goes thru the RCA's and can blow the internal noise shield fuse which protects the RCA's or as some people call it IT CAN BLOW THE EARTH TRACKS. These are only capable of withstanding about 1-2 amps of current any more and the fuse will blow possibly taking one of the tracks out with it.

So sorry about the long winded reply but this is the jist of why amplifiers fail in Commodores GENERALLY, unless of course it is entirely a product failure. In two years of running my business i had one amp come back the other which happened to be a Commodore where the customer didnt want to pay for an earthing kit but was recommended to do so. We measured the resistance to prove to him as to why the amplifier failed and once he saw the 6 ohm resistance measurement he understood what i was talking about at the beginning.