Grounding issue

[clamup1]

first off let me say i feel stupid for posting this.  i have built 3 pedals in a row and all three have 9v+ in the ground. i have taken all the caps and resistors that connect to the power rail off and i still get 9v+ in the ground. i checked for solder bridges and flux bridges and scraped off what i found. still the same. i used to use 1/16 solder b/c thats what i could find. i have since remedied this.

i just remade one pedal today. the guy who made the pc layout for me has built it twice and both worked. i dont know whats going on. help
This is the one i redid.

[chi_boy]

You may want to post a pic of the other side too.

Some voltages may help too.

Cheers,
George

[clamup1]

here ya go
Q1( upper one)
e- 8.47 b- 8.41 c- 8.86
Q2
e- 8.85 b- 8.86 c- 8.47

power rail- 8.89
ground rail- 8.47

[Hides-His-Eyes]

Even with a battery?

Is the protection diode the right way round?

Normally connecting 9v to ground gives you hot batteries.

[clamup1]

the diode is facing the right way. i hooked the neg lead from bat to the board and i get motorboating.(at least i think thats what that is) but i get rid of the 8.47.

i dont know if ive had a brain fart or different types of circuits need to be hooked up different ways. the offboard wiring is wired the same way ive wired my fuzz face. the fuzz works.

[chi_boy]

power rail- 8.89
ground rail- 8.47

Shouldn't one of these be zero?  Where are you connecting your meter?

Is the schematic you used online?

And what is the part number of that input jack?

[clamup1]

i connect my black probe to the middle rung of a stereo switched jack that you can buy from small bear. the schem is in on here somewhere. ill have to find it.

jacks-http://www.smallbearelec.com/Detail.bok?no=771

edit: schem

http://www.diystompboxes.com/smfforum/index.php?topic=89342.

11th reply

[vendettav]

here comes the awesome answer man. if you're using an adapter than i guess it's its fault

try this PSU thingy... worked like a charm adapter and now i can try out my crunch box clone XD

http://www.beavisaudio.com/projects/Huminator/index.htm

[twabelljr]

Are you plugging a cable into the jack socket to complete the ground circuit before taking measurements?

[clamup1]

@vendettav-nope no adapter. 9v

@twabelljr-ive never checked a pedal that way. but that would explain why my green russian bmp works when i use it for a gig. i got 9v+on that one too.mmmmmmmmmmmmmmmmmm

[twabelljr]

i connect my black probe to the middle rung of a stereo switched jack

I ask because if you are measuring from the middle rung without a jack plugged in the circuit is off and you are just going read the voltage potential everywhere. Plug in a guitar cable to the input jack to turn the circuit on and see if there is a difference in your readings. I may be misunderstanding, but your photos show the circuit board grounded to the sleeve of the input jack and the battery ground going to the middle rung.

[clamup1]

i plugged in a guitar cable and the readings where the same. ive always hooked the bat ground to the middle rung and then grounded everything else to the ring. i was looking at the tonepad offboard wiring pdf and they ground the bat ground on the ring.  im starting to wonder whether there was a lesson that i was supposed to learn before now that i didnt learn. or im just having a big brain fart.

[twabelljr]

ive always hooked the bat ground to the middle rung and then grounded everything else to the ring. i was looking at the tonepad offboard wiring pdf and they ground the bat ground on the ring.

That is the correct way to connect the battery and the other grounds to use the input jack to let power flow through the circuit when a guitar cable is plugged in. Cable out = effect won't turn on, cable in = complete circuit and effect will turn on. I also do not understand why you are reading +9v on ground. 'Tis confuising.  With the meter hooked up like you have it, I would expect to see +9v when touching the red lead to the positive battery lead and 0v when touching red lead to black lead. You should read 0v from the black lead clip all the way back to the board ground plane, if the circuit is using all of the voltage provided. If you read 0v when touching the black lead and +9v when touching the ground plane, then it seems like you must have an open ground circuit (that is why I suggested the guitar cable, to complete the circuit) If you read +9v on the black lead then +9v and ground are shorted together or there is a shorted component. But as was posted earlier, somthing should be getting HOT because the battery (or power supply) will be the source of voltage drop which is not good.

[clamup1]

sorry i missed the battery thing ill check it tonight.

im hopeing the resistors i bought off of ebay arnt bad. i got them in a grab bag type of thing. guy worked on the line on a major electronics company. the parts are from his pull tray. not all were pulls. but if they were on the tray were they bad.

which way is correct? the way i hooked up the jacks or the tonepad way

[chi_boy]

I would be suspicious of the input jack.  For testing purposes I would do a star ground OFF the jack.  Since things are goofy, I wouldn't even include the jack to start; but add it later.  Then you should have a clear path from the battery to the board.  To test, put your probes on the (+) side of the 47uF and the  (-) side of the 10uF cap.  The voltage should be the same as the battery.  If it's not, then the board may be cursed and you may need destroy it.

This may be a silly question, but you're not using a stereo cable are you?  ( I did that once  )

[thedefog]

It's hard to tell, but it looks like that orange/red wire coming from the mono output jack's ground is not going to ground, but to the spot in the board where lug 3 of the filter pot should go to.

[clamup1]

sorry guys im still here. we had to cut up a cow.

[rogeryu_ph]

I'm maybe wrong....Isn't guys when you use NPN germanium you need the ground negative not positive?
If you're Germ is PNP then the ground shoud be POSITIVE. On his part list it stated NPN Germ.  Don't know if i'm correct.....

[clamup1]

yes this is a neg ground pedal. with 9v+ in the ground.

@Chi- whats a star ground?. ill check the other thing tonight.

[twabelljr]

Have you read this: http://www.diystompboxes.com/smfforum/index.php?topic=90440.0 ??
There has to be a source voltage on one side of the circuit and zero volts on the other side. Some good test tips in there.