Fostex 3070 Power Supply Considerations and issue With Schem

[enginefire]

It connects c32 and r63... I have no idea what it does.  Both boards have them there factory installed from what I can tell.

 

[enginefire]

No c19 it's empty... Third and last time I'll write that.

 

[enginefire]

Do you also have a diode that connects to your c37?  To be honest I can't really follow what you are trying to describe about c19 c37 et al.  I doubt there is much to improve upon there anyhow.  I'm glad your caps have stopped exploding!

 

[enginefire]

I finally got around to this... I did the same mods as you more or less.  Recapped the power supply (didn't increase the value of the 10uf caps after the regulators!), changed the 1st 2 op amps to the 4562 (I'm a bit dyslexic), changed signal path caps (increased values) and some other resistor and cap changes.

I did one channel and it's definitely louder (so better signal to noise?) and seems cleaner, although that word can hardly apply to this compressor!  Such a dirty little beast.  Almost ugly sounding lol.

Did you ever play with that cap that would alter the attack and release times?

Did you ever try to mod anything in the compressor circuit part?  From what I can tell all those parts and in the signal path, and affect the compressed sound.  I imagine that changing out those op amps and surrounding parts would yield more improvements.

 

[Flapper]

With apologies for the thread necromancy... - I've reopened this thread since it seems to host some people with knowledge about this particular hardware.

I bought a Fostex 3070 off Ebay a couple of years back and it has never been quite right - for example the power supply light stayed on whether or not the power button was engaged etc. Nevertheless it seemed to work.

Recently, I can't get the compression functions to engage. - I press the compress buttons in and the input and outputs affect the signal, but the signal is not being compressed and I cannot get the gain reduction lights to show, no matter the settings used.

The expansion gate seems to work .

i) Has anyone encountered this, or have any ideas about what may have failed?
ii) Does anyone have the service manual?

Many thanks for any help.

Sam

 

[Flapper]

Hi Scott,

Thanks for the reply. I had forgotten that I'd taken the jumpers out! So I gleefully reconnected them thinking that it would solve the problem. Well - the expander seemed to work better but still nothing from the compressor function - the input and output pots affect the signal but the sound isn't compressed and the gain reduction lights fail to show anything.

Sam

 

[enginefire]

You might want to check your inputs and output connections.  If I remember correctly, I ran into the same problem if I reverse the ins and outs when plugging in the cables.