English Gent problem

[Lee Oswald]

It's such a simple circuit, how could someone screw it up?

I don't know, but I did. It passes signal in bypass. When switched on,
the LED lights up, BUT ONLY IF I DISCONNECT THE GROUND GOING FROM THE VERO BOARD
TO THE GROUND CONNECTION ON THE 9V INPUT JACK.

If I connect the ground from the board to the vero, the LED won't light. And there's still no sound.

I've checked all the values and placement, that's correct.
All the off board wiring is as it should be. I've scored the
spaces between the copper strips with a razor. The LED
has anode connected to the board, and the cathode going
to the 3PDT upper left corner. All wiring checks.

I'm thinking I must have gone wrong with all the additional grounding.
I've run volume 1 to the output ground. I've run gain 1 and 2 to the input
ground. The DPDT is going to output ground. I connected the DPDT switch
connection to the volume 3 lug, as the both connect to the board together.

I've re-flowed all solder points.

I've checked everything, and am at a loss. The LED behavior when the board is connected and disconnected makes me think I've messed up the grounding.

[IvIark]

What voltages are you getting at the transistor pins?  The working voltages always give you the best clue as to how close you are

[Lee Oswald]

Couple of questions in order to give you the voltages you asked for.

I've tried searching for a tutorial so I wouldn't have to bother you with
explaining, but no luck. So how do I use a DMM to check the voltages?

I assume I make the check with the ground wire removed so the LED is
functional, or does this matter?

[Lee Oswald]

|V|ark -

I don't know if this is accurate, as I don't know if I had my meter set correctly. And I don't know if I had all the information I needed, or if it was correct either. I asked around, and spent a good deal of time searching the Net. I never found anything specific to what we're discussing here.

My meter was set to DC, on the 20 volt setting. negative probe to ground, of course, and positive to each leg of the transistor. Here's what I found:

C: 7.08
B: 7.11
E: 6.63

If I did this wrong, just tell me what I need to do, I'll go back and do it again.

[rocket88]

to check the voltages at each transistor leg what you need to do is take the negative lead of your DMM and ground it to the enclosure, i usually just stick it in one of the screw holes for the back plate. then with the positive lead touch each lead of the transistor. write down what voltage you get at each leg, and make sure you have the pins in their correct location. it's that easy. which it sounds like that's what you did, so those should be an accurate measure of the voltages at each leg.

[IvIark]

The voltage on the base and emitter are much higher than I would expect.  I'd check for shorts between the base and collector rows, but if you're having no luck pot a front and back pic of the board to see if there is something obvious

[Lee Oswald]

Okay, so I did find a short, and i missed a misplaced lead on the protection diode.

But what really screwed things up is my failing to check the values of resistors with
a meter before installing them. Turns out my 2.2 Meg were actually 2.2k. Someone
at Tayda put the wrong thing in the little plastic envelope.

So it works. all that effort for something that sounds like an Electra Drive. What
a surprise. Although one mode sounds Vox-esque.

It also needs a tone control, it's too dark.

How much of a difference will 2 Meg make versus 2.2 Meg? I'd think it shouldn't be
audible, but what do I know?

[IvIark]

Negligible.  If it's too dark drop that 470n input cap right down to cut some low end.  It may be worth socketing so you can choose the perfect value for your gear.

[Lee Oswald]

Right. I'll give that a go. Thanks for bailing me out.