Aphex Model 300 Compellor not passing signal, meters read +9

[pvision]

I have a Model 300 Compellor.  It's in nice physical shape but won't pass audio unless it's in bypass.  I acquired it like this, though the vendor said it worked...

The meters read +9 (=red LED) whatever the settings of the meter switches or the pots

The in/out switch toggles the front panel indicator and the audio relays switch over.  The DVG LEDs light on power up and go out about 2 seconds later

I've checked all the voltage rails - there are two sets of ± 15 Volts (audio and control, I believe) plus a couple of other rails so the PSU seems good.  No signs of burning or damage anywhere.  It's running on 220 Volts and the PSU is correctly set

I believe these are no longer supported by Aphex.  Any suggestions on where to look next?

The fact that the meters read incorrectly and both channels act the same way suggests something is amiss in the control department

Nick Froome

 

[pucho812]

not sure if you have this...  Schematics and technical info are  in the back and in the middle is theory of operation. 

http://www.w3am.com/Aphex/Compellor_300_Manual.pdf

 

[pvision]

Thanks for that, Pucho.  I found the schematic a while ago and was looking at it whilst thinking about fault-finding

I think I'll check the +5V on every board next. Logically it's a logic / sidechain fault as it affects both channels equally.  I can't think of an audio board that would kill both channels but a PSU fault might

Nick Froome

 

[pucho812]

when ever I am looking at a unit that has multiple channels in this case 2,  and the unit has similar faults for both channels, I would look for what is common to both channels, which in this case is the power supply.  But at any rate with any unit, it's always good to make sure all the power supply voltages are in order.

 

[Brian Roth]

Indeed, measure the power rails at each circuit board, including using a local "0 Volt" point on the card.

Bri