ZX450 Green light -> No output

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Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

ZX450 Green light -> No output

Post by Stouf2406 »

Hello

Everything worked fine before today when I start my car and no sound.
HP have been tested with the autoradio and works.
Autoradio has been also tested with an other one in good condition to be sure that this is not the faulty and nothing happen.

Amps ZX 450 shows a green light , however fan does idle at power up.
I have tested the fan alone and it is working.

Any one have some ideas?
trickyricky
Posts: 1653
Joined: Sun May 06, 2012 8:01 am

Re: ZX450 Green light -> No output

Post by trickyricky »

Have you tried changing the amplifier's settings (xover fhz, xover hp/lp/bp)? If the amplifier powers up normally but has no output I would suspect the issue/problem be at the xover daughter board of the amplifier. Perhaps a wire from the ribbon cable broke right at the solder joint (seen this happen several of times).
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

I have checked all contact of the ribbon nothing wrong.
I have find something really strange : I have voltage between power connection (1V) and betweenremote and ground (4V) of course I have not powered my system : all cable are unpluged
trickyricky
Posts: 1653
Joined: Sun May 06, 2012 8:01 am

Re: ZX450 Green light -> No output

Post by trickyricky »

I don't understand what you are trying to say, are you saying you have voltage between the ground and positive terminals? If so that is normal as there is energy stored in the primary filter caps, you can discharge them with a 10-100ohm resistor across ground and positive then when powering up for the first time you can use the resistor inline (series) with the positive cable to slowly charge up the primary caps.

You'd need to know how the op amp IC's work (pin layout as well as the functionality) in order trace the problem down. I would start from the input RCA's and trace down the signal until it's complete lost or cut off for whatever reason. This may be a bit complicated if you don't have a o-silly-scope or know how the op-amps work as well as the pre-amp circuit. Might have to let someone with repair experience repair it for you. I can do so but there is a week turn around at the moment.
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

I understand that the cap are discharging.however why is there difference bet ween remonte and ac.
I m pretty sure this is a power issue as the fan doesnt work.
I m french and there is no amp doctor at affordable price.
trickyricky
Posts: 1653
Joined: Sun May 06, 2012 8:01 am

Re: ZX450 Green light -> No output

Post by trickyricky »

I still don't understand what you are measuring, remote and ac (what do you mean by ac?). It may be very hard to help if you are French and using a translator.
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

I mean by ac the main positive connection. I had no real reason to measure this voltage, but I was pretty sure that I have a powering issue( due to my fan not running but in good conditions).
I know it is hard to help and i thank you for trying.
This weekend i will have access to an oscilloscope and measure what you tell.
Have you some others things to do to find the origin of the issue?
trickyricky
Posts: 1653
Joined: Sun May 06, 2012 8:01 am

Re: ZX450 Green light -> No output

Post by trickyricky »

If it is not powering up then you should check the power supply fets and the gate resistors for those fets. You can check the fets with a dmm set to ohm or diode mode, you should not have any low resistance between any of the three pins of the fets. If you have a low resistance then the fets are bad and would have to be replaced.

Use a 5 amp fuse inline with positive cable for protection in case you short something while probing around. Also when powering up (applying voltage to the remote) keep an eye on the current draw with either a current clamp meter or a dmm (dmm would have to be in DC current mode and inline with positive cable just a like a fuse would be inline).

If you power it up and there is no change in current draw what so ever then you will have to focus on the remote circuit (there's some transistors in the remote circuit those sometimes go bad and cause the amplifier not to power up at all).
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

FETS have been checked : all are fine :(

Rechecked the wire from daugthter board one is not connected : the more on the right on right
I will rewire it this week end . I hope this the solution and not due to the manipulation
trickyricky
Posts: 1653
Joined: Sun May 06, 2012 8:01 am

Re: ZX450 Green light -> No output

Post by trickyricky »

Which daughter board? The Xover or the PWM daughter board (this one vertical). If it was one from the xover board then am afraid that will not help the situation, it could but I very highly doubt it as all it does is send the audio signal to the main amp board...you can power the amplifier without it if am not mistaken.
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

The wire is connecting xover board and main one...
Something to check on the Pwm one.
On powering i have red les during one second then green one steady. The fan is moving but does not launch.
Virtue
Posts: 132
Joined: Tue Apr 27, 2010 10:05 pm

Re: ZX450 Green light -> No output

Post by Virtue »

Check to see if you have a sound signal going into the amp...

If you have a signal, then you have a cold solder joint somewhere on the board. You will have to go though your board with a solder iron and touch up all major spots. Even resolder the input (RCA) jack. Might be loose on the board...
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

Ok but where can I check this out put signal?

Other things : My wife tell me that she has to use the battery charger. does this can be a cause ? I have an old battery charger and sometimes he goes in overload overvoltage mode.
Virtue
Posts: 132
Joined: Tue Apr 27, 2010 10:05 pm

Re: ZX450 Green light -> No output

Post by Virtue »

The amp has a protection circuit in it if your voltage is wrong. The yellow LED light (overload) will come on. Is this amp in a car or are you just powering up the amp with a battery charger?

The "input signal" I was talking about is the sound signal going into the amp... If there is no sound going into the amp, the amp will not make sound...
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

The batteur charger has been put in a car because the battery was down.
Audio source has been checked with ananother autoradio(working)
Stouf2406
Posts: 9
Joined: Sat Jul 30, 2016 5:34 am

Re: ZX450 Green light -> No output

Post by Stouf2406 »

The batteur charger has been put in a car because the battery was down.
Audio source has been checked with ananother autoradio(working)
Virtue
Posts: 132
Joined: Tue Apr 27, 2010 10:05 pm

Re: ZX450 Green light -> No output

Post by Virtue »

Since there is a signal and the voltage to the amp is good, then it is a cold solder joint on the circuit board. You will have to pull the amp apart and start touching up key joints with a solder gun. Touch up all transistor solder joints that get hot and main power bars that supply power to the transistors.

If you don't have the ability and knowledge of doing this, you will have to get someone to do it for you.
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