Chevin Research A1000 schematic required.

[MrLayout]

Hi, I am new to this forum. I am an electronic engineer by profession but more on the digital side - not too good with analogue stuff!

I am trying to repair a Chevin Research A1000 power amp for a friend and was wondering if anyone has any schematics for this or similar amp.

Fault description: Channel A seems to work fine and the fans are Ok too. The output from channel B is noticeably distorted but seems to be about the correct volume, I think. Nothing inside looks obviously burnt, or anything.

Any help would be gratefully received!

Thanks.

 

[dungdochi1978]

you can take some picture,and everybody will help you

 

[dungdochi1978]

which transistor they use on this amp?

 

[MrLayout]

Problem Sorted!!

Hi dungdochi1978, thanks very much for your reply. I managed to get in touch with someone at Chevin Research, called Martin, and he was able to help me with the repair. Once I took the heatsink off it was obvious that one of the ECF10N20 MOSFET's had self destructed with a flash! I tested all the remaining MOSFETS on that channel and found another two that were suspect, one was a ECF10P20.

Martin gave me the source for the replacement MOSFET's - Profusion PLC. I have since ordered the transistors, fitted them and the amp is now working very well. It has been returned to its owner and he is very happy with the sound of it!

There was also a problem on the power supply input. The relay that switches the live had blackened contacts but was still working - I swapped it with the neutral switching relay as it has little current going through it and was in perfect condition. Also the resistor in series with the relay coils was well burnt so I replaced it with a higher wattage vitreous wirewound type.

I now know loads about these amps and would be very glad to help anyone else with problems with them.

Thanks again!

 

[dungdochi1978]

Great!!
did you have schematics now. i search it on internet ( it is seem not correct..) .Can you sent it to me! thank ( dungdochi1978@gmail.com)

 

[MrLayout]

Hi again dungdochi1978, at first I was told that they do not give out schematics but then Martin did send me the schematics but asked me to keep them private. I must respect his request as it would be wrong not to.

I will send him an email and ask if he minds me sending them to you and will let you know his reply. In the mean time if you have a specific problem with one of these amps please let me know and I will do whatever I can to help.

I did do my own sketch of the power supply mains input section before receiving the schematics and could send you a scan of that if you like - let me know.

 

[dungdochi1978]

Hi again dungdochi1978, at first I was told that they do not give out schematics but then Martin did send me the schematics but asked me to keep them private. I must respect his request as it would be wrong not to.

I will send him an email and ask if he minds me sending them to you and will let you know his reply. In the mean time if you have a specific problem with one of these amps please let me know and I will do whatever I can to help.

I did do my own sketch of the power supply mains input section before receiving the schematics and could send you a scan of that if you like - let me know.

itis ok .
i like it .i going to make one amp ( to much choices when make a amplifiers classA,Ab..).i search on internet see too much -also this amp A1000 .i only want to confirm 100% all detail on schematic is correct. only main matter is difficult to buy orignal Tranzistor ( hight quality,..).
up to you !!Thank

 

[wgdanson]

Hi Mr Layout. I have a A1000 which has blown some of it's o/p transistors. Do you do repairs, where are you, and the rough cost of replacing these parts please.