Help diagnosing mixer

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losthighway

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Making the move up from my 4 track, I picked up a Fostex 80 recorder and 450 mixer off ebay and I'm having some trouble with the mixer. It powers up but when there is an input signal it doesn't make it to the outputs. The peak led will light up if I turn up the trim knob but only the faintest sound makes it to the headphones (the meters on the recorder don't even pick it up). I was, however, able to listen to a tape through Aux 2 at regular volume. What could be wrong?

Haven't found anyone locally who will look at it so I'm trying to figure out if I could fix it myself or I should just take the hit and buy another one (and do my homework this time).
 
Are you sure that you are operating the mixer properly, routing the signal through the various paths by pressing the correct buttons and turning up the corresponding levels controls?

Are the jumper pins missing from the access/send/recieve jacks?

Do you have the manual?

Here's a link to it if you don't;

http://home.hccnet.nl/r.h.sijmons/pdf/fostex450manual.PDF

Cheers! :)
 
I did read the manual several times. I'm pretty sure it's set up right, it's pretty simple... 8 outputs > the recorder and from those outputs to the tape ins on the board... not using the busses. But even simpler than that, shouldn't I be able to just plug a keyboard into the line in, engage the input, turn up the trim, and hear something in the headphones? Moving the faders has no effect at all, and it's the same on all channels.

jumper pins missing from the access/send/recieve jacks?

I don't know what that means... how do I check?

Thanks for the help. This forum is a great resource.
 
the fact that you played the tape back on aux 2 makes me think your screwing up somewhere in the master section.... take a deep breath and check your routing assignments.... take it logicly....
 
losthighway said:
I did read the manual several times. I'm pretty sure it's set up right, it's pretty simple... 8 outputs > the recorder and from those outputs to the tape ins on the board... not using the busses. But even simpler than that, shouldn't I be able to just plug a keyboard into the line in, engage the input, turn up the trim, and hear something in the headphones? Moving the faders has no effect at all, and it's the same on all channels.



I don't know what that means... how do I check?

Thanks for the help. This forum is a great resource.
Page 5 of your manual describes the access send receive connection point I am talking about. If there is no connection made between these two points, no sound will pass through from the initial input stage onward to the eq, pan, level and master section of the board.

If you look closely at the front cover picture of your manual, you'll see these little black colored "jumper pins" which are in place to allow the sound to travel through when no effect processor is plugged into there.

I've read through the manual and they don't clearly spell out this pitfall but I'm pretty it it's there and this is just another case of a manual being very poorly written.

If you don't have these jumper pins, simply use a short RCA to RCA patch cord to make this connection and that should solve the problem.

Any clearer now?

Cheers! :)
 
You, my friend, are a saint. Now... where can I buy these jumper pins?

edit... like this?
 
Last edited:
losthighway said:
You, my friend, are a saint. Now... where can I buy these jumper pins?

edit... like this?
Seeing as I'm not Catholic, I don't know if I can be elected to Saint status but thanks for the kind thoughts! :D

As for the jumpers in your link, those are for 14mm spaced RCA jacks so, take a ruler and measure from the center of the send jack to the center of the receive jack and if it's 14mm, those will do quite nicely. If it's only off by one millimeter, you might be able to bend the jumper slightly to fit. Otherwise, consider making your own jumpers or using a short cable like I mentioned in my previous post.

Cheers! :)
 
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