ROG Omega Verification

[texstrat]

I just finished building the ROG Omega and I get nothing when the effect is engaged, but do get bypass. Looking over the documents can someone verify that the PCB layout for Q2 is wrong and should be reversed.

Here is the schematic with the perf board layout and they are showing power, 9V, coming into the Drain, http://runoffgroove.com/omega.html.

The PCB layout shows the Source receiving the power, http://runoffgroove.com/omega-pcb.pdf.

As I was building this, I was looking at how the semiconductors were oriented on the board.

Thanks.

[anchovie]

Depends on the MOSFET that you're using. The parts list says you can use 2N7000 or BS170 and they don't have identical pinouts. The PCB silkscreen is correct for 2N7000 but for BS170 you'd have to rotate the part.

[digi2t]

I'll second anchovie on that one. Check your pinouts. I've built it, and works great.

[texstrat]

I am using the BS170. I will rotate and check if it is working properly.

How sensitive are the BS170? Is it fried because I put it on the board in reverse?

[davent]

Not necessarily, i've made the same mistake in other builds and had no issues simply using the same mosfet in the corrected orientation.

dave

[bluebunny]

+1

As MOSFETs go, the BS170 seems pretty robust.  The first Millenium 2 board I built (on vero) had the thing on the wrong row - desolder, resolder.  Then it was the wrong way round - desolder, resolder.  Now working like a dream, despite my best attempts to nuke it...

[texstrat]

+1

As MOSFETs go, the BS170 seems pretty robust.  The first Millenium 2 board I built (on vero) had the thing on the wrong row - desolder, resolder.  Then it was the wrong way round - desolder, resolder.  Now working like a dream, despite my best attempts to nuke it...

I was smart enough to solder pins in place for both in order to play around with different MOSFET's.

Just to be sure, am I setting the drain voltage bias to the 2N5457?

[davent]

Yes, schematic says 4.75v.

Get yourself some in-line sockets and cut off what you need to create sockets for you transistors then swapping becomes a real simple exercise. Lots of sources.

http://www.smallbearelec.com/Detail.bok?no=101

dave

[texstrat]

Yes, schematic says 4.75v.

Get yourself some in-line sockets and cut off what you need to create sockets for you transistors then swapping becomes a real simple exercise. Lots of sources.

http://www.smallbearelec.com/Detail.bok?no=101

dave

Thanks Dave 

[artifus]

i've chopped up dil packages in the past to make transistor sockets... if you're short on specific parts can be a useful resource. necessity is the mother of invention, etc.

[texstrat]

Well I switched the BS170 around and still nothing in effect mode, time to break out the audio probe. 

[digi2t]

Just one more thing...

There have been reports, and I experienced it myself, that it might crackle when adjusting the volume (DC across the wiper). See this thread for the fix;
http://www.diystompboxes.com/smfforum/index.php?topic=82570.0

Basically, put the pot after the 4.7uF cap, and you can get rid of the 1M pull down resistor.

It's a great booster. Used with a fuzz, it's a great solo kicker. I love it. Built it into a silicon Skyripper, just fantastic.

[texstrat]

Just one more thing...

There have been reports, and I experienced it myself, that it might crackle when adjusting the volume (DC across the wiper). See this thread for the fix;
http://www.diystompboxes.com/smfforum/index.php?topic=82570.0

Basically, put the pot after the 4.7uF cap, and you can get rid of the 1M pull down resistor.

It's a great booster. Used with a fuzz, it's a great solo kicker. I love it. Built it into a silicon Skyripper, just fantastic.

Digi2t:

Thanks for the heads up on this. Right now I get nothing except a low scratchy sound when I strum the strings hard and a bit of crackle when I adjust the 10K pot.

[texstrat]

Found the problem, a bad solder joint on the ground leg.