soundcraft spirit folio sx help

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plastik01

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Joined 2010
#1
Hi.

After doing some searching on the net i managed to find the schematics and also this place and the various threads it has about this range of souncraft related mixers and their issues.

I am hoping that someone may be able to offer some advice.

The mixer has been sat for a while since it had an issue. When powered on the mixer would work fine, but sound would only come out of the sub outputs. if i routed it to the main mix from mono there would be nothing, if from stereo there was a very quiet signal with the gain and faders up high, and also some slight popping/ crackles.

I have taken the mixer apart to see if there is anything obvious, the psu is good and the mixer condition is excellent. I have been told to replace the 5532 driver as that is a commmon issue, the full code on the ic is:

5532
6054b
jrc

the only other thing i can think of is prehaps the 072b op-amps also on the main sat down inbetween the faders.

I am hoping that either uk.rs or cpc have these in stock.

can you suggest anything else to check?, the insert jack contacts are closed properly and there are no issues there. I cannot see any caps blown or leaking.

The fact it works through the sub outs sureley means its at the main ouptut stage input point or in the stage doesnt it?

thanks

si
 
#2
The 5532 is a stereo op amp, both RS and Farnell will do them, look for NE5532N.
I've had the little coupling electrolytics go open on these, sometimes the top is domed a little. Check the output driver supply buffer resistors, sometimes one or both of these go as well especially if the chip has been fried by something nasty hooked to the output sockets. Also check the output buffer resistors themselves on both main mix out and around the main insert sockets as these may have been blown.

Hooking an amp to the output and doing a screwdriver hum test around the op amps will help you to narrow it down more quickly.
 
#3
thanks forthe reply kev. I have sent you a pm with a few q?'s hope you dont mind.

I really do not want to throw this mixer as everything bar the main out works! wierd thing is that with the main faders down to nothing i still get some sound through, if i put them to half way the sound is loudish but still distorted, if i push them to full the sound gets quieter, the same the other way.

If i can get this one last thing sorted out it is something i can get some use out of again.

thanks for your help.
 
#5
here is the main schematic, as you can tell i am not overly sure what to check, i have the 5532 and op amps replacements on the way with the 330 uf caps as well for replacing. Can someone point me to the components that kev is referring to?

here is a part of the full schematic for the main out section.
An externally hosted image should be here but it was not working when we last tested it.


thanks

also here is the main link to the full schematic pdf. Soundcraft SpiritFolioSX Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics
 
#6
i changed out the 072b and the 5532 op amps i also checked them on other channels just to see if they were good and they are fine , so i replaced them when it was not needed. ok so im stuck now as to where to look for this signal issue and what is causing it.

if the caps were the issue i cannot tell, none have burst or leaked anywhere and none are even domed, so perhaps it is the resistors kev mentioned above, however i have no clue where to even start testing the signal chain.

if anyone can help it would be great , thanks.
 
#7
Isolate the problem.

Your left and right INSERT jacks feed right onto the master fader - look at the schematic. If you feed a test signal into those inserts, does it come out the main outputs? Likewise since the signal gets to your subs, does it come out those inserts?

Since both left and right are affected, we first look for things they have in common. My very first suspect is the main fader itself. Other than that, apply a signal to some input then follow it along. The main circuit flows through IC3, IC4, the insert jacks, the main fader, and IC5. Look for the signal at each step.
 
#8
the first test i did was the inset point as this is after the initial input feed in the schematic, the sound was clear from the insert to the main out using the fader as volume control.

i also removed c28 and c16 which are pre the insert point to rule out any current being pulled back.

r35/r65 both read 75 ohms, and r36/r66 both read 47k so the insert resistors are fine.

I am now inclined to just replace everything from ML/MR feed in to c16 + c28.

Wierd thing is the sub section is exactly the same circuit and the measurements i get from that match the main section.

The main faders are good as is proved when used for the insert feed volume.

So i have got the function generator and scope out today and i will inject a signal into the unit and do a trace through the signal path from the main input to the insert point which I know is good.

Other than that a complete master section rework may be in order as the parts are less than 10 bucks to buy.
 
#10
Hi,
I need to obtain the SX diagram, I've been to the factory in Potters Bar, and they said email them, which I did, but no responce, tipical UK company. I've tried the link you give for the pdf, but says can't find. The diagram you've give shows the area for one fault, but a channel (9) has also decided to die, so can you please help with a diagram. From what I read hear, I suspect duff coupling Cs
Thank you
Peter
 
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