20 Most Recent Crest Audio CC4000 Amplifier Questions & Answers

Hello folks, The same thing happening with my crest cc4000. The plastic connector, connecting the wires from the transformer to the circuit board was burnt damaged and was removed. but acl light still stays on and amp not active.

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on; or it may turn on but produce no audio to the speakers.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'nekkid'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as another possible root cause for intermittent shutdown.

The power transformer is getting short and overheated causing it to go in thermal protection mode.Also if the amplifier gets overladed by its connection, it goes to thermal mode.
The problems i have seen most often in Crest amplifiers is bad capacitors. They look fine from the outside but pull one out of circuit and measure it and there bad. These are the small electrolytic types. there are 2 sets of solid white wires from each output module to the output relays. Inject a a signal into the amp and take a look at the signal on those white wires. If the signal looks clean with minimal DC offset then you have bad caps causing it to stay in thermal protect. A very common crest amplifier problem.
Check in between the heatsink's. These amps have a tendency for those heatsinks to arc across the sinks. There are only 2 thin rails that hold the modules and rough tour duty service can cause those rails to bend and the sinks to touch and arc. Even a bug getting between the sinks can cause them to arc if the amp is running hard!
Also look for open resistors. This are possibilities, that can cause the amplifier to remain in thermal protect mode. ------------- This should help.Thanks.Helpmech.

Dust in the unit - clean with Canned air like a computer.

or Delamination on the printed circuit board.Don't forget to clean all contacts on the backside of the unit!

If cleaning doesn't work - head to the local Crest "AUTHORIZED" Service Center.

You could use the EQ but it won;t sound as good as it will with a pre amp and also could make it a bit trickier when adjusting the volume and getting it to sound right.

Hi E:You directed this question at me, but unfortunately this isn't my expertise and I am unable to provide you with a real solution at this time. Hopefully one of other experts will be able to provide you with a real solution. Thank you for using FixYa.

The pre amp. inside the amp. is burned. A local shop can most likely fix it for about 100.00.