Beginner Problems with HF Mod

[daverdave]

Howdy,
I'm pretty new to electronics and very new to this forum, I am currently on my forth project, the jen HF Modulator, I used the layout from GGG, and used 2n3094s. I've probably bitten off slightly more that I can chew here as the other pedals I built were very simple. I finished it the other day but the effect doesn't work, the signal is going through the box when activated but is not affected with the exception of the tone knob, which seems to work OK.

Does anyone know what the problem is most likely to be or could it be a number of things, thanks.
Dave

[Pushtone]

Hello and welcome. I'll be putting this one together soon as well.

Since you are getting un-effected sound the problem might be around the Intensity and speed controls part of the schematic.

Looking at the GGG schem, thats everything left of C6.

What are the voltages on Q2 and Q3?

You DID use the right layout and the right pad holes for 3904s, right?

Any part substitutions?



See this thread for debugging posts too.
http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

http://www.diystompboxes.com/wiki/index.php?title=Debugging

[daverdave]

I'm positive I used the layout for the 2n3094s, and I didn't use any part subtitutions. One Thing I kind of did wrong, which is a little embarrassing, is I used 18 gauge wire, which is kind of cumbersome for me to work with. I managed to get everything wired up, but a few of the solder joints broke loose on the board while I was wiring it, I did repair them but another might have come loose without me noticing.
As I said, I'm pretty new to this. Because of the wire I can't get to the underside of the board that easily, but I'll give it a try tonight and get back to you, thanks for the reply.
Dave

[Pushtone]

I imagine that the 18awg would make it very hard to trouble-shoot. Yikes!

I find all my wire. I've never bought any.
I currently use the inside conductors from microphone snake cable at 24awg.
It's super easy to manage and if you do the "pcb weave" or use header screw sockets, they never break off.

But I have been known to stop in a back lane and strip all the wire from a dead computer put out for the trash.
Their power supplies use 18-22awg 600v wire - good for amp builds
Several hookup wirers inside for the speaker, CD audio, front lights etc use 24awg wire thats good for stompboxes.






Off-board wiring is such a pain that builders are forced to find techniques to deal with it.
To compound things, the way the PCB board is mounted will impact the off-board wiring.
These factors are intensified if the builder is aiming at a smaller enclosure or a lot of off-board controls.

Here is an old thread where many express their frustration and some solutions to off-board wires.
http://www.diystompboxes.com/smfforum/index.php?topic=43322.0

I have totaly gone with the pcb weave technique. I have not had a single broken wire since.
It would work for your 18awg wire if you where bent on using it, which I don't think you are.

The PCB WEAVE
Leave some extra board space on one or more sides of you pcb/perf/vero etc.
Drill small holes near the pads where off-board wires connect.
Weave the wire through the hole as strain relief.
Solder to the pad. Works great! See...



If the pads are spread out around the layout, like on many ROG projects,
I will drill a line of holes along one side and form a little loop over the components to the pad.

[daverdave]

That's a pretty damn neat technique, I'll remember that one but I don't plan on using this 18gauge wire for anymore stompboxes.
The problem was I bought it from Maplin and didn't think to check the system they use for their wire sizes. So I saw 24/0.2m and thought it was 24gauge, when it was actually '24 strandes of 0.2mm wire'. I bought some 7/0.2m which apparently the equivelent to 24awg.

So I think I might be wise starting again on this one, I'll keep the case but do a new board, I had a poke around in it last night but it's a literal web of wires, so I can't get to anything that easily. At least I've learnt something from this experience, thanks.
Dave