Numark N4 MIDI Controller Problem

[Getherer]

Hi guys,

I've bought a Numark N4 MIDI controller some time ago, about a year ago.
My warranty is already gone and I am away from city where I bought it at the moment, so in the meantime I thought someone may have some knowledge on DJ'ing and configurations around here.

Basically, some time ago whenever I start mixing, after some time (usually was varying, sometimes 30 min, sometimes 1h, sometimes 50 seconds...) my controller started to make a buzz sound, and then it goes silent. At first, my equalizer (built in on the midi controller, or gain meter, whatever you want to call it) was still running, but no sound was being passed on to headphones nor speakers. So then I had to power it off completely and wait some time, around 10 minutes until I could switch it back on and it would start working... until it did the same thing over and over again. It kept doing it both with PC software as well as standalone (it has a built in sound card) while connected to vinyl decks.

Now, the gain meter/equalizer does not flash at all, so as if no sound is actually being passed through the controller to software on PC or standalone. However software (Traktor PRO 2 or VDJ, any of them...) was acting as if music is being normally passed on, but no sound was made.

Device manager says that N4 is installed properly and it works without any problem.


Been looking for any similar problem over the web, but without any success.


Has anybody got any idea what it could actually be affected by?

I just hope it isnt something serious, as my warranty already ran out....

[Darkvision]

The bright side:it isnt a driver issue


Down side: when devices make sounds they shouldnt be...its NEVER good. Obviously its sounds like something was having a heat built up issue, probably bad part from factory considering how quick you are having the issue.


Solution:take to a shop, replace the unit, or....


take it apart locate the bad part through site/smell. look for burnt looking or smelling part(s) and replace using ye trusty old soldering iron. if you can not see or smell a bad part then break out a volt meter and test each component(make sure current goes through each individual capacitor etc). then replace with good part(s)


Also look for burnt/cracked/touching wires or parts. look for bad solder joints (quick google search to what good and bad joints look like should suffice) replace/repair if needed. it its just wires touching something they shouldnt then simply insulate where they are rubbing. if a wire(s) have burnt through their shielding then they used to low of a gauge of wire in its construction or used seriously inferior wire. get a higher gauge wire/new wire and replace it.

[techb]

If you could provide schematics that would be nice.

With a multimeter and/or/also an oscilloscope, probe the output on the board and see where the signal is stopping.

My guess, without testing myself, would be a bad filtering capacitor or a faulty opamp or other chip.
If something was shorted I would assume it wouldn't work at all. Overheating like mentioned could also cause the problem. If a diode in the bridge rectifier, assuming mains as power, goes bad or a decoupling capacitor then you have problems.

With anything though, I notice caps go bad quicker than other components cause of the electrolitic fluid dries up.

Again, you'll just have to poke and prod till the issue is isolated.

[Darkvision]

I probably should have mentioned on the capacitors to look for obvious phsyical deformations such as bulging or leaking. techb is right in saying that bad capacitors are very common in electronics, especially the lower end ones. But yeah since its almost certainly a hardware issue its going to take a lot of poking/prodding/looking/sniffing to find the issue(or at least it can take a lot). This kind of thing though cant be done "fast" it takes experience, which you get through doing just what we are suggesting. you could make the problem worse than it originally was, but considering it isnt working and out of warranty you have nothing to loose but the money invested in the proper tools to investigate.


Should also note that it is NOT always feasible to fix a problem even if you find out what went wrong, the replacement part(s) could still cost more than buying a new unit or close to the cost of a new unit. Another option when you have located the bad part is to buy another broken unit that you know broke in a different way and take the good parts and make a new "good" unit. Again not always feasible but it is a potential solution when you locate the problem.

[Getherer]

Thanks for your replies guys, I will have a look inside and see whether I can distinguish any issues.

I couldn't find any schematics on the web, the only thing available is the quick start pdf with... basic manual of what the controller consists of (exterior ofc).

I don't have time to check it now, but I will do within couple of weeks, so would appreciate if the thread stays open until I get some time to come back with some info to you guys.