Buss Comp acting up, meter goes to 20 reduction when on-SOLVED

[mjlaudio]

Hi Everyone

Im dealing with an issue with my ssl 4040e/g+. The center cards are all late revs g series.....

The buss comp meter goes to 20 when I turn it ON and the attack is set at 3ms,10ms,30ms.
It slams to 0 when ON and at .1, .3 and 1

I can't hear any noise but the 26card vcas are distorted bad sounding.

I don't have center section extender cards, but I do have service manuals

I have checked voltages the +15v and -15v points measure +13v -13v so Im assuming the 27 card is not properly supplying 15v to the vca's
The 18v and 12v, 11v, 5v points all look good

I dont have T11, and T12 fitted. Theres no regulators for the 18 down to 15, It looks like this is happening with capacitors instead.c20,21,22,23 don't look bad.

T1 which is an LF351 is what is driving the meter here and its powered off the 18v rail. The 18v rail seems ok. But it could be a bad LF351

I don't have extra pieces so I need to order stuff.

Wondering if theres any more suggestions or if I'm looking in the wrong places.

Water from an ac started dripping on the channel strips, I caught it quickly and turned the banks off. I am experiencing oscillating on some eq cards. I am going to replace the heat shrink on the backs of the eqs(02's). Hopefully that will fix those. But when I powered up again the center section was acting like it is now.

Any Help is much Appreciated


EDIT:
The Meter just stopped bugging out and is working correctly....the 26 card still is distorted......all the eq's just stopped oscillating as well. I didn't do anything it just stopped.


EDIT2:
This was definitely caused by moisture on the 26 card. Specifically the long resistor run on the back of the card.

Thanks
Matt

[horizonsound]

Hey Matt,

I have a similar issue I am working through. The comp works fine, and meters fine when engaged, but jumps up to over 4 when disengaged. There is no noise on the buss that I can detect.
Regulators on the 027 were changed out a few months back due to being out of spec, but not sure yet what is causing this.

Anthony.

[mjlaudio]

It appears this was all related to moisture building up on the components on the back of the cards' heatshrink. I changed it out and things are getting back to normal.

[horizonsound]

That damn heat shrink again!
Not to mention the corrosion on the solder joints.

Does anyone have a good method for cleaning up the corrosion, other than mechanically scraping at the solder joints?