Chevin A2000 Schematic

Hello, I have a Chevin A2000 on my bench and channel B clip LED is constantly on.

Hi my name is Cameron Jenner ,
                                                 I run the world wide Chevin Research repair service www.chevinresearch.co.uk 07889252455 . you do not have a genuine A6000 drawing as it does not exist . The A6000 is in fact 2 x A3000 Mono Blocks !!! I have the origional set of drawings from the Chevin research Factory and these have never been in circulation . I also have all the build and test equipment from when the amplifiers were hand built in uk .
You should check what fets are installed in the A2000 If they have a colour assighned to them then they are graded . You only need  1 duff unit to cause the problem you are describing . If this is the case you need to examine each fet and establish which units are bad and replace with the matched colour or you will have more trouble .
I am happy to help you with this and supply you with the origional parts as required .
I belive that these amplifiers are still superior to anything available today even though they are nearly 20yrs old in design and I will help out anyone who needs it.

Kind regards
Cameron Jenner


Edited by cameron - 28 February 2015 at 1:14pm

Hi Michael,

It still does sound like a FET problem, how did you check the FET's ????, the best way is to de-solder the gate & drain connections on all the FET's on the faulty side, check one pair with a FET tester and then re-solder and try the amplifier on a small load and check the clip light again, if the fault goes then a faulty FET is the problem. I usually do this and check every FET with a MOSFET tester and then re-solder one at a time when they test o.k., when the amplifier has a signal feed into it does channel B sound distorted in any way ?????.

I have had a Chevin in for repair when the clip lights came on (both), but the amplifier worked o.k. and then after about 5 minutes the faded and went out, i checked every part of the clip circuit and just found it was down to humidity.

I am based in Brislington. Please send me a PM and i will foward diagrams.

Cheers

Simon


Edited by simonp1100 - 28 February 2015 at 2:24pm

Hi
  I would be able to fix this for you in 5 mins . The channel is protected for a reason .Either there is dc at the output or you have a failed output transistor . Without a scope prodding around with a multimeter you will be there all day and still will probably not get anywhere. This is why people complain about the amplifiers because they do not have the facilitys to diagnose and test in the correct way ...
Usually the fans die the amps overheat and fet out , but this is due to a lack of maintenance . The fan circuit will not cause the protect light to illuminate .
You can check the fets with a multimeter in situ you do not need to do anything other than measure the gate resistance to find the problem .
I would be happy to do this for you if you get stuck , just interparcel the amp to me at :

unit 19 ellingham ind est
Ashford
Kent
Tn23 6nf

Kind regards

Cameron Jenner


Edited by cameron - 28 February 2015 at 2:41pm

Hello Cameron,

cameron wrote: (quote) Simon This is like having a noisey wheel bearing on your car and removing one wheel at a time and driving it slowly and repeating the prosses until the noise has stopped ... This is not how a garage would diagnose it and could be hazardous  dangerous and possably do more harm than good !! sorry for the analogy, but please dont hurt yourself amplifiers have large capacitive charges and you could die , be safe . regards cam There is nothing wrong with isolating all the FET's and testing them with a FET tester (amplifier OFF and isolated from the mains and POWER SUPPLY CAPACITORS DISCHARGED), so long as when the amplifier IS powered up there IS A PAIR (P & N) OF FET's connected to the circuit.

Edited by simonp1100 - 28 February 2015 at 3:33pm