Numark C3usb - how to replace a fuse

There is not an internal fuse.

The bad news is it could be any of them. or it could be the lighting- CFL's and regular flourescent lighting are bad for audio, as are switching supplies used in TV's, microwave ovens and some musical gear. They are worse than lighting dimmers for noise.

The thing to do is start at the speaker itself and work through the chain of devices to find the one distorting. An old transistor radio is useful here. Most actually do have enough power to faintly drive a large speaker- listen for scraping and rattling- it would mean the voice coil windings may have come loose or the coil form is damaged from heat.

Move back to the amp input and try again- this time listen for a clipped sound if the speaker checked out okay. It would sound like the Charlie Brown adults in the cartoons. That would be a failure of an active component in the amp. If you now hear rattling or scraping- the speaker voice coil is bad and should be repaired or replaced.

If it sounds good, move back to each deck. apply your radio- volume turned down to an input it one is provided. Each should sound clean like the amp did. If no sound or distorted sound is found here- which is the most probable location, it is likely one of the IC chips is at fault. Likely a 4558 if an IC fault, otherwise suspect dirt or hair on the encoder connected to the spin platters.

This should help:
http://www.numark.com/images/product_downloads/cdn25_quickstartguide.pdf

You do need an amp.and a mixer. You mixer should have microphone jacks, and a pream or switch to allow you to use lowZ, High Z or amplified microphones.

There is something a bit more serious than the fuse. I would start by checking that the speaker itself is the correct type. This should be a 8 ohm speaker. Then I would play it and see if the output transformer is hot. This may be over driving the speaker. I would also look at the main power transformer. You might have one with the export transformer which can work with 110 or 220. I have no idea of your location so no idea which is your local level. Something is either over volt or over amps. Most of this amp runs at 15 volts and digital runs very cold compared to a tube amp.

I looked over the schematic and I just can't see anything else that would do that other than the things I have mentioned. A hot speaker is "very"unusual. If you can check the voltages with a meter this should be easy to point out the cause. It shouldn't take much for a amp tech to sort it out if you have to take it in. I wouldn't run it that much until fixed. When you see abnormal heat then something is being stressed. So you can cause more damage by using it. There may be a problem with the power transformer or votlage regulator stage but since the speaker is heating that could end up needing replacement if run too long.

Without having it in front of me I would sayy you may be looking at a new power transformer.or diodes and possibly caps. Any of those could cause the base issue. This is different enough with the hot speaker than I'm not that sure without seeing it.

Hallo! This is caused by the laser fault. First unplug the cord, high voltage!!! Disassemble the device, look under the cd place you will see a little lense. Clean it VERY DELICATE with a piece of cottonwool with alcohol, can clean it twice with alcohol and then with a dry one. If doesn't help, then need to replace the laser reader system with a new one, it's that where the lense is placed, it must have on it an badge with the serial number, you can search it by that number/code.

No problems doing this. Just make sure to power the amp and the Mix 3 from the same receptacle or power conditioner. Remember IF you are using the EQ functions of powered speakers you will NOT have those when going directely to an amp.

If the fuse has blown, it did it because of a failure within the unit. Replacing the fuse MAY cause additional components to be damaged. It is likely the fuse will blow soon after replacing if not immediately. Take unit in for servicing. The unit has high voltages within that if you are not experienced can be lethal. If you are lucky, a vacuum tube has shorted that caused this. If they are changed the amp will need to have bias checked and adjusted.

Try the following sites

http://www.powerstream.com/power2.html

http://www.platinum-records.com/Numark-21V-750MA-AC-Adapter-Power-Supply-prod7509.htm

Or even a cheap replacement laptop power supply as these usually start at 1000 mA which will give you current to spare and have a longer lifetime. most of these cover from 15V to 24V and are either auto switching or manual select for the voltage. Plus you can pick these up from most electronic / big box / supermarket shelves

i'm having the same problem, just wondeered if you found any solutions to this?