Gssl turbo board mistake

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migidee

Well-known member
Joined
Jan 10, 2010
Messages
60
Please help! I goofed up big time hooking up my gssl turbo mod and accidentally flip flopped the connections to the control board and swapped most importantly the 12v and C solderpoints and fed my turbo board +12v to the output and vice versa.  I also swapped the -12v and 0v with the G and D points.  I didn't test the voltage before I started and when I turned it on it somewhat worked but was outputting extremely hot signal.  after I figured out the mistake and rewired it I plugged it back in and was not passing audio on the left channel. When I powered it up and down there was a slow peak in signal on the left side but no audio passing.  I tried swapping the vcas in the L and R audio path and it worked in standard mode again, but now it appears the turbo mode(which is switchable) does not appear to compress much/at all compared to the standard setting.  My suspicion is it's only getting half the signal when in turbo mode).

So I guess my question is where should I start looking to fix it?  Did I burn up my turbo sidechain vca and/or tl074?  Did I burn up anything in the left channel audio path?  Should I replace all the vca's and/or opamps for good measure?  How does one test a vca to see if it's working short of plugging it into the working part of the circuit for comparisson? 
 
OK I am pretty sure the tl074 is fried. I am ordering a replacement.  Is there anything else I should check for?  Anything I should be concerned about
 
try switching out opamps....I hope you socketed them! :) I hate making silly mistakes like that...the other day I accidentally plugged in the power transformer to the output of a circuit board! Wha! luckly only a resistor was fried and smoking.
Good luck!
 
Thankfully all opamps and vacation are socketed.  But I don't have a spare one laying around.  It doesn't appear that anything is noticeably toast but its hard to believethe opamp survived +12v in the backdoor.  I may just replace all the vca and opamps just bto be safe.  Thanks for the help I appreciate it.
 
You'd be surprised how much and how little it sometimes takes to break an op amp.  
I would be very sup prized if everything got fried. I would check your turbo board and it might be worth your while to wire up a pair of cheap old school headphone and tie one side to ground and a 100uf capacitor and a piece of wire to poke the inputs and outputs of the opamps, that way you can hear your signal and then just follow it through the input opamps, to the VCA to the outputs and see where your left side signal gets stuck. really helps with cutting down on the guesswork.
Goodluck
 
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