SSlmixed.com Forum

Tech discussion => 4K,6K,8K Series => Topic started by: jwhmca on October 23, 2014, 01:39:40 AM

Title: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: jwhmca on October 23, 2014, 01:39:40 AM

Hi Guys,

Look at the resistor on my VCA card! I was recapping the 26 card and put it back in and saw smoke. Nothing was shorted or bent or anything like that. The problem went away after I removed all the conductive sleeving on the 27 card.

Does anyone know what that resistor is doing? Like, is it fusable and one of the VCA's was getting too much power or something? I can of course replace the resistor and just try it again... I just didn't want to hurt anything.

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: sintech on October 23, 2014, 06:59:30 AM

Yeah, the 027 card provides the +/- 15v power to run all the 026 cards VCA's

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: pascal.verdet on October 23, 2014, 09:07:43 AM

Hi,

As show by the picture, I think that the resistor was on VCA board ...

Cheers,
Pascal

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: jwhmca on October 23, 2014, 04:47:13 PM

Right...

But why would this resistor burn?

Is the vca in the schematic?

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: sintech on October 23, 2014, 06:36:55 PM

This burnt resistor is connects to the SYM pin on the VCA, so it's just part of the distortion trim side of the Audio VCA.

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: jwhmca on October 23, 2014, 07:36:27 PM

Safe to put another card in there and try it? Or just replace the resistor and try it?

I have other little VCA cards from the Channel strips. Are they the same VCA card?

Title: Re: Quad Bus card VCA burning! Strange issue on 27 card the cause...
Post by: sintech on October 23, 2014, 08:07:31 PM

Yeah, it's the same VCA