PDA

View Full Version : Need some electronics assistance



wintertidenz
01-10-2013, 10:13 AM
I have a Phoenix Gold AX-406A active crossover that provides the correct signals to my amps to power my 3-way front setup.
Recently it has been playing up, and usually a wiggle of the wiring gets it working, but now it won't work at all.

The remote input is receiving 1.6v when the wire isn't even in place, and the crossover will not power up when 12v is applied to the input.

I have pulled it out of its case and it smells slightly of burnt electronics, but I am unable to isolate it.

Is there anyone here that can point me in the right direction? I can provide images of the board and voltages of the points.

Davezj
01-10-2013, 01:31 PM
there is a classic case of wiring being a bit flakey, you move it and the signal comes on or the signal goes off.

this is quite common, and usually it is a dry joint in the soldering on the connector that the wire is connected to. So to repair it you just run some solder and an iron over the connector pins on the PCB in question.
sometime you can actually crack the PCB if the connector is on a jutting out bit of the PCB and it does not have much support.
I layout pcb for a living so as long as the pictures are clear and of a reasonable size i might be able to talk you through some diagnostics you can do. noting special just measuring some resistances and vltages.
post up some pictures of the PCB and we can have a look at them.

darren1976
01-10-2013, 05:34 PM
Try gordan at amp doctor very good at repairs

Davezj
01-10-2013, 05:57 PM
Try gordan at amp doctor very good at repairs

Is this Amp Doctor in New Zealand, if not it is a long way to go, lol.

wintertidenz
01-10-2013, 09:29 PM
I will put up some pictures tonight, thanks.

I measured voltages this morning and there was still 1.6v on the remote line with no wiring connected! So I am now thinking that a cap has gone on it.

When 12v is applied the delayed remote circuit works as expected, but the rest of the crossover just doesn't power up.

wintertidenz
02-10-2013, 05:35 AM
Here you go.

The crossover outside for reference - the third one along is remote, and the last one is delayed remote.

64578

64576

64577

Having it light up the LED with 1.6v and putting out the same voltage on the remote line makes me think that some component on the board has failed and is leaking voltage to the remote circuit, when it should be isolated.

darren1976
03-10-2013, 04:01 PM
Sorry didnt see where guy was from but he is from southern hemersphere so might be able to help

Davezj
03-10-2013, 04:36 PM
I have a Phoenix Gold AX-406A active crossover that provides the correct signals to my amps to power my 3-way front setup.
Recently it has been playing up, and usually a wiggle of the wiring gets it working, but now it won't work at all.

The remote input is receiving 1.6v when the wire isn't even in place, and the crossover will not power up when 12v is applied to the input.

I have pulled it out of its case and it smells slightly of burnt electronics, but I am unable to isolate it.

Is there anyone here that can point me in the right direction? I can provide images of the board and voltages of the points.

Firstly i would look at the power in, if you say the unit is not powering up.
what is being applied to B+ B- R DR, there is a fuse inside is that ok?
What is normally connecting to the remote low pass level input/output? is there normally anything connected to the phono jacks (bass low pass out)? or are you just using the tweeter and mid output?

it is very difficult to try and help without being able to get your hands on the electronic equipment infornt of you.

wintertidenz
04-10-2013, 05:33 AM
The fuse is fine, I've replaced it. I get 12v across the fuse and into the circuit. I'm able to trace this through part of the circuit but I haven't spent a massive amount of time testing every point. Ground is fine.
The remote wire powers up the unit and tells it to turn on - this appears to be where the problem lies. When voltage is applied to this circuit, the unit doesn't power up. The delayed remote side turns itself on after a second as expected, and sends power to the amps (anti-thump).
The LED to indicate power glows very dimly - this normally only lights up once the remote wire is connected, and indicates that the crossover is on. I get 1.6v across this LED.

Usually there is an input, and three outputs as I run it three-way active.

The cap that bridges the remote and ground circuits is retaining voltage after the system is off - I would expect this to bleed off the rest of the power and be at 0v, but it can hold its charge overnight.

Davezj
04-10-2013, 01:25 PM
The fuse is fine, I've replaced it. I get 12v across the fuse and into the circuit. I'm able to trace this through part of the circuit but I haven't spent a massive amount of time testing every point. Ground is fine.
The remote wire powers up the unit and tells it to turn on - this appears to be where the problem lies. When voltage is applied to this circuit, the unit doesn't power up. The delayed remote side turns itself on after a second as expected, and sends power to the amps (anti-thump).
The LED to indicate power glows very dimly - this normally only lights up once the remote wire is connected, and indicates that the crossover is on. I get 1.6v across this LED.

Usually there is an input, and three outputs as I run it three-way active.

The cap that bridges the remote and ground circuits is retaining voltage after the system is off - I would expect this to bleed off the rest of the power and be at 0v, but it can hold its charge overnight.

to be honest diagnosing over the web is a bit tricky, i don't even know which input you are talking about when say the remote input, there is a 4 pin power in terminal with B+ B- R DR on them, what are you feeding to which terminal. there is also a RJ45 type socket next to it that has remote low pass on it and this is the only connection that is marked as remote, are you talking about this connector when you say the remote connector, or something else.

wintertidenz
04-10-2013, 11:02 PM
B+ is 12v constant. B- is ground. R is the 12v remote signal input that turns the crossover on. The DR is the delayed remote circuit (anti-thump).

The RJ11 connector is for a remote adjustment unit that I don't have.

Davezj
04-10-2013, 11:44 PM
B+ is 12v constant. B- is ground. R is the 12v remote signal input that turns the crossover on. The DR is the delayed remote circuit (anti-thump).

The RJ11 connector is for a remote adjustment unit that I don't have.

Right that make much more sense, oh to have the board infront of me with a DVM.
i will have a think.

Davezj
05-10-2013, 11:49 AM
terminolagy when i say "bell out" i mean do a resistance measurement or continuity test to check the 2 points are connected.

firstly you need to bell out from the R terminal to the next component on the board it connect to The resistor just behind the connector is the right place to check it. this probabley where the connection is lost if a dry joint is the issue. and the connection was made or broken by wiggling the wire originally.
if the connection is present , while belling out, you need to wiggle the power in connector and see if the the connection is still there or if it cones and goes.

either way if the connection is not there or intermitant the you will need to resolder the power in connection joints and put new solder on the joint not just reheat the joint.
re test the joint by belling out and wiggling.

wintertidenz
07-10-2013, 06:08 AM
I just ran over all the joints with my Portasol butane iron and some fresh solder to help reflow anything, but it didn't make a difference.

I've made a list of all the resistances and traced it back until it hits the +12V line by the fuses, hopefully this will give some light into the problem. I labelled which components I could recognise (I suck at reading resistances off the resistor itself, so if you need a higher quality picture of that area from the front, I can provide it).

64673