Loud Hum...Grounding issue? If so, where is this coming into play?

elenore19 · January 30, 2011, 11:09:34 PM

My gaussmarkov Pearl Octaver build that I've rebuilt many times trying to get it to work.
I plug it in and there is a loud hum. And the is signal from the guitar is not making it through, but when I press on the guitar jack (when not plugged into the guitar) the hum responds to it.

Other than that, i can't get a bypass signal. So I assume it's a grounding issue, but I can't figure out what would cause this. Is the ground making connections with the signal path? Or....

Thanks for the help!

-Elliot

Here's a picture of the guts. (taken with mac computer, so it's "backwards")

familyortiz · January 31, 2011, 04:05:44 PM

Elliot,
If it worked before your latest mods, I would take a multimeter and check the resistances of any new connections as well as the ground connections, to make sure things are connected ok. Take your time and do it in a methodical manner from in to output... you'll find your problem.

elenore19 · January 31, 2011, 09:25:09 PM

Quote from: familyortiz on January 31, 2011, 04:05:44 PM
Elliot,
If it worked before your latest mods, I would take a multimeter and check the resistances of any new connections as well as the ground connections, to make sure things are connected ok. Take your time and do it in a methodical manner from in to output... you'll find your problem.

The pedal hasn't worked yet.
That's my problem. I've fixed a lot of things with it and I'm just trying to get past this grounding issue.
I figure since I can't get a bypass that there is a wiring issue.

Jhouse · January 31, 2011, 10:10:06 PM

You are right to assume that. If it doesn't pass any signal when bypassed, the wiring is wrong. How did you wire this bad boy up?

I can't tell from the pictures. It's like a spaghetti monster. Haha.

elenore19 · February 01, 2011, 12:28:47 AM

Quote from: Jhouse on January 31, 2011, 10:10:06 PM
You are right to assume that. If it doesn't pass any signal when bypassed, the wiring is wrong. How did you wire this bad boy up?

I can't tell from the pictures. It's like a spaghetti monster. Haha.

Yeah, I've rebuilt/rewired this pedal 2 times now, I decided this time around I'd leave plenty of wire to get access to both of the boards to make my life easier with debugging.
I use this wiring http://gaussmarkov.net/wordpress/thoughts/wiring-up-a-1590b/
Positive I have it wired up correctly now. Sorry about the spaghetti...
NEW PROBLEM THOUGH!
I got bypass and a signal through the board.The only problem is the controls don't work. They all do something, but I can't hear any octaves going on. The lower octaves don't really add lower octaves, but more of a muffled more bassy sound. (As if the tone pot on your guitar was turned down) The upper octave adds a trebly sort of sound to it, more sharp. But no upper octave.
The trim pot doesn't affect the upper octave at all either, so I'm sort of stumped as of right now.

Any suggestions?
I'll start a new thread soon about it.

Jhouse · February 01, 2011, 12:31:18 AM

Give us all the info THIS bad boy asks for and I'm sure one of us on here can certainly help you. Glad to hear that you got it to bypass though! We just need a bit more information to help you

elenore19 · February 01, 2011, 02:15:31 AM

Yeah, I've been trying to avoid doing that beast.
But I'll get it done soon and hopefully I can get this thing up and running.
Thanks for the help guys.

-Elliot

familyortiz · February 01, 2011, 10:59:51 AM

Ellliot,
If you're pretty sure the board is wired correctly, when starting to look for the obvious, an easy place to start is to check the power supply voltages at the chip and wherever it's at on the board as well as your grounds. If things seem kosher, then you gotta do the troubleshooting at a component level, but like the man said, there are plenty of resources here. good luck.

petemoore · February 01, 2011, 11:54:12 AM

I've been trying to avoid doing that beast.
Once you get to know him, you will begin to appreciate how he's your best bud if you have a bug. When just looking at it doesn't find the bug, the only choice is to unleash the beast in there...once he's working for you and has trained you, he'll find every bugger, every time.
After a while you won't be able to count the # of times you and the beast simultaneously realized the super-obvious-to-both-of-you bug-fix solutions.
If you can't get through it you can get around it...there's always another patch you can try.

thedefog · February 01, 2011, 03:50:19 PM

The best thing to do is to test out a board PRIOR to wiring up any bypass switches or jacks (input/output and power). You want to eliminate any possible contributing factors to something not working before adding anything. I learned this lesson after spending hours debugging about 10 builds that had nothing wrong with them other than faulty wiring.

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Loud Hum...Grounding issue? If so, where is this coming into play?