Soundcraft Spirit FX16 Mixer problems

[MikeC1980]

Do the output meters show any activity? That would start to narrow down where the problem lies.

Probably the output opamps, most prone to abuse, right? I have the FX16 schematic at home, parts are identical to the SX that I have. Its out on the web too...

[bitman]

Ta-Da! - Sorta

Here is a link to some FX8 schematics which I believe are a scaled version of the fx16.

I have one too.
I's a mixer on a board so it is a bear to work on. All smd chips too.

Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics

:Ron

[ewhiz]

There is no doubt you guys have steered me in the right direction...
Upon further research through Harman's tech support, I'm told exactly what the both of you told me all along. The tech at Harman said that it's probably either a bad driver[5532] or problems with the insert jack plug(INS). When I get some extra time, I plan to tear into this board and diagnose whether it's the insert jack or op amp. BTW, the service tech at Harman said that he would email a schematic and the modification procedure for this board to create another sub-group. That's pretty good PR!

[bitman]

Originally Posted by ewhiz

There is no doubt you guys have steered me in the right direction...
Upon further research through Harman's tech support, I'm told exactly what the both of you told me all along. The tech at Harman said that it's probably either a bad driver[5532] or problems with the insert jack plug(INS). When I get some extra time, I plan to tear into this board and diagnose whether it's the insert jack or op amp. BTW, the service tech at Harman said that he would email a schematic and the modification procedure for this board to create another sub-group. That's pretty good PR!

Would you mind forwarding it and the mod to me at:
ron ATTTT mtrecording Period KOMMMM ?

I would much appreciate it.

[2N1305]

when I received my used Allen&Heath System 8 mkIII the outputs were also "non-functional".

Or so I thought.

It turned out that you had to trigger the PFL input to activate a relay that would route the signal to the outputs. Weird. I still don't understand why someone would design or want that. So check your board for PFL engage switch.
Or it might be jumpers missing on the circuit board.

Surface mount, he, you'll have fun if it's the first time you work with that!

Good luck!

2N1305

[rthally94]

Sorry for such a late response. I have a spirit fx8 with very similar problems. When I run sound through the mains, It is nonexistent unless the gain and fader is maxed out. The sound is very scratchy and unintelligible and the meters show the same. I checked the mix inserts and they are performing fine as is the direct outs, control room, and aux lines . Now the sub out is doing the same thing. I have cleaned all the faders 1/4" jacks with deoxit and the problem still exists. Any help would be much appreciated. Thanks!

[Ike Zimbel]

Sounds kind of like the output coupling caps are toast. Do you get more HF out than LF?
Best,
Ike

[rthally94]

Thanks for your reply!! Oddly enough the sub outs are currently working as of 5:38 EST with the macbook run into rca inputs on channels 9/10 and 13/14. The main outs are still halfway working. When they run at very high gain the speakers play a distortion of what i would assume to be the low end or mid-highs (snare drums). The meters respond accordingly to the output of the speakers. Mix inserts are still working. The monitor outputs mirror the sub/mix depending on which is selected. If anyone needs any further info please let me know!

[rthally94]

Under further investigation I have found the problematic area. It is somewhere between the mix insert and the mono sum. Is the OP Amp somewhere in this area? If not what would the likely fix be? Thanks!