Grrr Audio problem, is it the Amp broken?

[SeanyK]

Hey folks,

Right, I have a standard Cupra HU, but I have wired it up to a Sony (yes I know!) X-plode 4/3 channel amp (has hi-level inputs). With sub in back.

Been like that OK since about Dec 2004.

Week before last, there was no sound coming out from any speakers, I checked the 2 '25A' fuses on the back, I think one was blown, couldnt fully tell because of the rubbish fuse design so I changed BOTH anyway just to eliminate that.

Nothing... The radio / CD is on and playing but no sound...Then all of a sudden, it came to life, (About 5 mins into it being on lol).

For the last week it's been ok, but last night, not working at all, now not working, I changed fuses again, nothing.


I've checked all the wiring, the earth cable, the power cable, the power cable fuse, battery connection everything, but no joy.

Is the Amp finished?? I know the Sony ones are rubbish, and I only bought it because it was cheap and did what I needed it to.
I have a feeling I'll be buying another amp.


PS> It's worth noting that i've touched NOTHING to make this happen.

 

[cordobabrendy]

could be dry joints (not sure how much of a circuit board is in it, but if its intermittant...), sony amps arnt expensive so might be cheaper just buying a new one or maybe a 2nd hand better make.

 

[SeanyK]

Hi mate,

Yea, I changed the fuses AGAIN, checked wiring AGAIN.

No power LED on back of amp coming on... So definately a power issue.

But power cable seems fine, fuse looks fine.

New Amp I guess, definately not buying another Sony!

 

[Jammy]

Hey there, sounds like its dead, though you have checked the remote turn on? just supply it with 12v bridged straight from the +ve.

JAmes

 

[SeanyK]

Hi James,

What does that mean mate? Sorry you have to be really basic with me, whats a +ve?

And whats a 12v bridge?


I take it you mean just put a wire straight to the remote turn on on the back of the amp?

 

[cordobabrendy]

+ve means positive connection

 

[Jammy]

yeah the remote turn on needs to be supplyed with 12v. I'm guessing who ever put in the amp came up with a suitable wire and used this. but you should check it.

It probable says "remote" on the back of the amp, attach a bit of wire to the +ve (positive = red) and stick it onto the remote bit too. Then you defo know your getting the turn on signal.

hth
JAmes

 

[SeanyK]

Ah ok I get ya!

I fitted the amp myself ages ago, I bought a 1000W wiring kit, I know the bits you mean now mate, ok so ill just get a bit of wire and stick each end one to power one to remote and see if it works.

If it doesnt, new amp time right?

 

[Jammy]

I think so bud.

ebay time

JAmes

 

[SeanyK]

Tried it just now.

Connected wire from rem to + connection...


The power light went on for about a second, then off.

I then tried it again and again, connecting the wire proper with screws to hold it in etc, nothing whatsoever.

 

[Jammy]

bahhh hard lines, I'd guess that theres a packed in capacitor or something in the amp then, only last thing i can think of is that the subs have blown and are causing the amp to auto shut off.

In a last attempt disconnect the subs and try and turn it on. Either way, one of them is broken.

Do you have uprated speakers at the front of the car running off the stock HU? I'm looking into what speakers people are using for a mate. i dont run the stock HU and so dont have a clue about what does and doesnt work/fit.

JAmes

 

[SeanyK]

My setup is a 12" Pioneer Sub, & Pioneer Components at the front, I think they are something like 171C as the model code.

No rear speakers just the sub in the boot.

The speakers are wired from the doors directly to the amp speaker level inputs, using the rear speaker cable for the signal.

The only connection from the head unit is the remote lead I believe.

I did wire it all myself but a long time ago (2004) lol so I can't remember if I used the back of the HU for anything else.


Tommorow ill disconnect the sub wire and see if that makes any difference.

Don't fancy buying one online i'll prob end up down Motormania or GK's some shop like that.

 

[SeanyK]

Bought new amp, tried it, no joy.

Good job I bought it from a local shop and not the net!!!
Took it back.

Im gonna take the headunit out tommorow, Im sure I saw some fuses behind there... I'll check all connections too..

If that dont work I need to get hold of a multimeter and check if power is coming to the cable.

 

[SeanyK]

(Feel like im speaking to myself here lol)

Anyway changed the fuse at the back of HU, checked wires, re-checked fuse under bonnet, everything all connected.

Still no power to the AMP, guess I have to buy a multimeter from Halfords now to check the cable is receiving power...

 

[andythom]

Have you double checked your earth to the amp?

Heard if you have used the seatbelt bolt as an earth they work loose

 

[Icecavern]

sounds to me like a shorted speaker cable sending the amp into protetion.

 

[SeanyK]

I re-fitted the earth cable, no joy.

I think a multimeter is the best option, if I can rule out the power cable being the problem, then I can start to work on other things such as speaker wire.

There is a LED for protection, thats not lit

Can I read voltages from speaker cable? What should they be if I can?

 

[andythom]

What is the amp running?

Components and the sub?

My mate has 2 DB audio subs running from a legacy amp and the continued heat and abuse caused a capacitor to break off, him being an alarm fitter (handy) soldered it back on and it was back to the norm....

He was having the same symptoms.....

If you know any one thats electrically minded, get them to open it up (disconneted from the car obviously ) and check all of the capacitor "legs"

 

[SeanyK]

I'd elimated the amp mate as I tried another one remember.

Sorted it...


What is was was the Fuse near the battery (The huge one) Even though I'd checked it twice already, it was completely intact...

I prodded the power wire in the boot with a electrical tester, it was receiving no power, checked it BEFORE the fuse, Power...So changed the glass fuse, and voila it works!

Apparantly the fuse has dry solder or something, common in the glass fuses?!

Glad it fixed, only cost £2 for the fuse lol

 

[Jammy]

doH! well in

JAmes