Help to fix C-Audio RA3000 Amp

[Kevin.Frost]

Hi All,

I need help fixing a C-Audio RA3000 amp that's been a great workhorse for our amateur theatre for years.

I've examined inside but can see no obvious failed components.

The symptom is that it powers up, but does not work!
Also there is a single LED permanantly illuminated at the bottom of the left VU display - that's probably some form of error indicator I guess?

I have some electronics knowledge, but I'm no amp expert.
Any help appreciated
Thanks, Kev.

[burbeck]

Hi kevin,
we have an expert on the forum for c-audio amps, Lee Basham (do a search for his contact details)
failing that i could help you as i am familar with these units myself and i am just down the road from you
regards
bob

[ben goh]

Hi

Does the output relay clip? If not, check the protection section

transistor BF423 and resistor 180k

Thanks

[Kevin.Frost]

Ok - I guess the first thing I need is a schematic! Can anyone send me a schematic for the RA3000?

One other piece of info - the "Protect" LED comes on briefly during power-on but does go off (I think this is normal) - and there is no output from the amp at all!

Cheers, Kev.

[ben goh]

Hi

I do have the schematic for the RA3001

Can I post it, is it legal?

[Kevin.Frost]

Ben,

Can you send the schematic direct to me?

unfortunately because I'm a new member, I can't send you an email directly. If you are unable to send me an email you can contact me using the following link:

http://www.concordiatheatre.co.uk/in...on/contact.asp

Select "Theatre website" as the contact - I'm also the webmaster for the theatre as it happens

Cheers, Kev.

[ben goh]

Hi Kevin

Let me dig out the schematic, scan and email to you.

Thanks

[ben goh]

Hi Kevin

I can't attached files in your website.

Do you have other email?

Thanks

[Kevin.Frost]

Yes - I have a few email addresses, but I don't like them posted on forums where they can be collected by web crawlers!

Just send me a "Hi" message to "Theatre Website" as in previous post and I will reply to you so then you will have my email address.

Silly I know, but it helps cut down the spam I get!

Cheers, Kev.
and thanks for helping me on this one!
Oh! and if I don't reply straight away it's 'cos I'm on holiday next week - Yeah

[lee.basham]

Hi Kevin,
The first thing to do is figure out which part of the amp is faulty.

you say it runs up but doesn't work do you mean it's in protect?

If you put in a signal (off load, no speakers connected) and turn up the volume does the bar graph light up as notrmal, check on both channels. if it does then the fault is likely to be in the protection circuit.

if not then you have probably got a DC offset somewhere on the offending channel.

if you give me a call on 07768551482 I can probably talk you through how to fault find it to component level.

thanks

Lee Basham