madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: murdog47 on November 26, 2014, 11:21:42 PM

Title: Why am I not getting signal past Q1?
Post by: murdog47 on November 26, 2014, 11:21:42 PM
I did a layout of the RAH circuit and am not getting signal past the gate of Q1. Here is my scheme and layout. Anyone?

(http://i1077.photobucket.com/albums/w466/pmurray47/RAHSCH_zpsfb50eaa1.png) (http://s1077.photobucket.com/user/pmurray47/media/RAHSCH_zpsfb50eaa1.png.html)

(http://i1077.photobucket.com/albums/w466/pmurray47/RAH_zps455d47e7.png) (http://s1077.photobucket.com/user/pmurray47/media/RAH_zps455d47e7.png.html)
Title: Re: Why am I not getting signal past Q1?
Post by: alanp on November 27, 2014, 05:00:33 AM
I've been playing this game too long. I look at the layout and my mind immediately starts making suggestions.

Are you sure your BS170 is good? Those are ESD sensitive, IIRC.
Title: Re: Why am I not getting signal past Q1?
Post by: wgc on November 27, 2014, 03:20:51 PM
Agree with Alan, swap q1. Also double check the pin out. I've screwed this up more times than I want to admit...
Title: Re: Why am I not getting signal past Q1?
Post by: murdog47 on November 27, 2014, 04:09:34 PM
Pinout is correct. I'll try swapping the BS170
Title: Re: Why am I not getting signal past Q1?
Post by: madbean on November 27, 2014, 04:42:04 PM
Never hurts to breadboard a problem area. That section would onlybtake a couple of minutes.
Title: Re: Why am I not getting signal past Q1?
Post by: Stomptown on November 27, 2014, 08:44:54 PM
The trace from the drain if Q2 looks aweful close to the  gate  pad. Did you run the drc to make sure it wasn't too close? If so, maybe there is a manufacturers error there??? I would make sure there is not continuity between the drain and gate pads.