Help with Scrambler

[foozertone]

Yeah I did that and they are correct

[PerroGrande]

Is there any way you can post a couple of pictures of your board - top and bottom? 

The voltages on the first stage (Q1) are still nowhere near the expected value for the Base and Emitter.  (The values you post are with no signal input, correct?)

I'm sorry we haven't made more progress on this.  There is obviously something going on that isn't good -- several simple voltage dividers R2/R3 and R12/R13 are not producing expected values. 

[pedalmaker]

Perro,
Its cool to see someone intent on helping another person like what you are doing.
BTW, Im having similar probs with my scrambler.

[foozertone]

I could try to take a pic with my scanner but I haven't figured out how to post pictures.

Sorry

Jeff

[Austin73]

Jeff, to add a picture you need to register with a online pic store such as snap fish, image store photo box etc (googel them)

Then once your registered you need to up load the pics to THAT site then you can post on here using the link above second from left on second row and add the link inbetween just like using the web address insert.
Hope this helps

And look forward to checking out your PCB as I know how frustrating these things can be especially if you bought the board

Aus

[foozertone]

http://www2.snapfish.com/slideshow/AlbumID=180654414/PictureID=4112621841/a=111652638_111652638/t_=111652638http://www2.snapfish.com/slideshow/AlbumID=180654414/PictureID=4112621841/a=111652638_111652638/t_=111652638

I hope you can find these pics. This is the best quality I have available.  I hope this helps.

Thanks

Jeff

[foozertone]

I wanted to add: I took my readings with a guitar cable plugged into the input and not connected at other end.

[foozertone]

Perro? Anyone?

[geertjacobs]

Two general remarks:
- what you can do is check the schematic whether all points that should be at 9 volt are really at 9 volt and whether all points that are at 0V really are at 0V.
Same for any voltage dividers present.
- you can make an audio probe (see FAQ and search) and trace your guitar signal. Plug in you guitar and follow the signal through the stages from the input to the output. This may help to locate any errors.

[PerroGrande]

Sorry, Foozer -- been a little busy the past few days.   

As you suspected, I couldn't see much from the pictures.  I hope it is blur I'm seeing and not solder globs.    Globs will get you every time.  I remain at least somewhat convinced that you've got some solder making a bridge somewhere that it shouldn't be.  With a commercial board like you have, basic wiring errors are all but eliminated.  Assuming you've got the right components in the right place in the right orientation, things should fly.  That leaves pretty much the solder goblins as one of the few things that can actually go wrong... 

From the pictures, again - might be blur - there are several suspicious areas where it looks like solder might be touching from one trace to another.  If you can get some solder-wick to help clean-up the board, it might make things a lot easier.

Checking for 9v and 0v is a good start, as is the audio probe (a worthwhile tool to build if you don't have one and plan to do more pedal building).   

[8mileshigh]

It looks like you're iron isn't hot enough because you have huge globs of solder.  What solder are you using ?  I bet you're got cold spots and shorts in there.

Chris

[PerroGrande]

Remember, when you're soldering, the tip of the iron is heating up a bunch of stuff... The right stuff needs to get hot enough, and the wrong stuff shouldn't get too hot...

The "right stuff" is:

The component lead
The copper on the trace surrounding the hole
The solder

These need to get hot "enough" for the solder to flow, bond, and do its magic...   When this doesn't happen, the results can range from globs to infamous "cold solder joints" -- all of which cause connection problems and malfunctions. 

However, other stuff gets heated along the way --

The pc board itself
the component
hopefully not your fingers!

If the board gets too hot, the traces and/or the adhesion of the trace to the board can become damaged.  This is often referred to as a "lifted trace" and is almost always the result of too much heat for too long a period of time.   Likewise, if the iron is too hot and spends too much time in contact with the component lead, the component will get hot (via its lead wire) -- sometimes to the point of damage.

So the most common mistakes are:

Too much iron movement (reduces the effective heating, pulls solder around, creates cold joints)
too much solder (creates glops, messes, bridges, etc.)
messy iron tip (makes heat transfer less effective, hard to tell how much solder you're using, deposits solder where you don't want it, etc)

When I solder, I make sure the tip and tip side are making good contact with both the copper trace and the component lead -- the iron is reaching its target at a bit of an angle, not straight down.  Hold it steady for a *moment* and add some solder.  When properly done, the solder will flow -- actually be *pulled* onto the copper.  Remove solder and iron nearly simultaneously.  The resulting solder joint should be shiny and shaped a bit like a "solder volcano" with the lead emerging from the center.  You never want to see solder balls, glops, etc.  The diameter of the solder should *never* exceed the diameter of the trace/pad... 

With your board, I would get a solder sucker or some solder wick and remove the excess solder.  Just like with soldering, de-soldering/cleanup requires careful attention to overheating.  Heat up the joint enough for solder to flow and then fire the "sucker" and get out of there!

[foozertone]

Thanks Perro for being patient with me and trying to help me succeed. I gues I need a little more practice with the iron and thank you for your tips for that. Maybe one day I can build a pedal. I've actually built two (An Orang Squeezer and a Tweak-O) but I've 86'ed a handful (or two) more than that.Still thanks so much for all your help. Do you know anything about breadboarding. I wannamake a breadboard layout for a Tweak-O (from Small Bear) so I can experiment with it. I just got a breadboard and I did the IC breadboard project posted elsewhere in this forum. Ii doesn't distort but hey at least it makes sound . That was somewhat helpful but I still don't understand how to make a layout out of a schematic.

Thanks

Jeff

[8mileshigh]

Jeff,

I'm willing to try to get your Scrambler working for you if you want to send it to me.  I bought a board last week that needs trouble shooting so I'd be debugging two at the same time. No big deal.  Just thought I'd offer is case you decide to abondon it forever.  I'll ship it back when it fires.

Chris

[PerroGrande]

Jeff,

No worries -- we all have to start sometime!  I still think the problem with your Scrambler is probably solder related -- and soldering just takes practice.  Sounds like Chris is willing to give you a hand with the Scrambler.   

I do quite a bit on a breadboard -- nice way to try circuits, ideas, etc.   I made myself a collection of different lengths solid wire to use with my breadboard so I can save some time in the construction process. 

Converting from a schematic to a layout -- well, this too takes practice.  A lot of projects have a vero layout already provided, and that can give you some ideas about how it is done, in general.

In short, the lines on a schematic indicate electrical connections.  On a circuit board, these connections are made with traces.  On a breadboard, the connections are either made via the common rows on the breadboard or with wires.   A reasonable way to start with a breadboard and a schematic is to work your way through the schematic in "signal order" -- from input to output -- typically left to right on the schematic.  Go left to right on your breadboard.  This won't necessarily make the most efficient layout, but will work and will give you some practice.  As with all things, start simple and go from there.  Simple = basic boosters, buffers, etc. 

Also -- search around on the web. A LOT (virtually all) schools that teach electronics involve breadboarding somewhere in the process.  I'd be willing to bet money that there are additional tutorials out there on breadboarding -- including translating schematics.  I'll see if I have something that can help, too.