Author Topic: [fixed] Friedman Golden Pearl Overdrive but the OD does not work  (Read 251 times)

FuzzyFaceFuzz

[fixed] Friedman Golden Pearl Overdrive but the OD does not work
« on: December 28, 2020, 01:28:09 PM »
Hello good people of diystompboxes!

I have been lurking here for a couple of weeks and learned a lot wile doing so. I'm new to building effect pedals, and I'm loving it. I've been having lots of fun wiring and debugging my creations. But this pedal is starting to get under my skin. I have spent many hours of trying to find the problem and can't find it. Is there anyone out there who can lend me some circuitry wisdom?

1.What does it do, not do, and sound like?
Sound is coming through when the guitar is plugged in and the battery is connected. The sound is clean. Volume pot works as expected. Gain pot does nothing except after about halfway, then it cuts the volume completely. Tone pot does nothing. Switches do nothing. 

2.Name of the circuit =

Friedman Golden Pearl Overdrive

3.Source of the circuit (URL of schematic or project) =
http://tagboardeffects.blogspot.com/2019/11/friedman-golden-pearl-overdrive.html

4.Any modifications to the circuit?

No but instead of mounting the leds to the switch i made a small vero and connected them.

5.Any parts substitutions? If yes, list them.

The tone pot is 22k lin instead of 25k lin

6.Positive ground to negative ground conversion?

I donít know. But the circuit has negative ground.

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? =>
8v

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = 6.59
Voltage at the circuit board end of the black battery lead = 0

IC pin (LM833)
1 4.42
2 4.08
3 3.71
4 0.1 (mV)
5 3.86
6 3.86
7 2.629
8 7.86

Checked all electrolytic capacitors and the voltage is higher on all the positive legs compared to their negative legs. All pots have been checked and their values are ok.

Thanks, Eli
« Last Edit: December 28, 2020, 02:16:53 PM by FuzzyFaceFuzz »

FuzzyFaceFuzz

Re: [fixed] Friedman Golden Pearl Overdrive but the OD does not work
« Reply #1 on: December 28, 2020, 02:18:59 PM »
Just needed to post here to find the solution.  :icon_lol: sorry.

Kevin Mitchell

Re: [fixed] Friedman Golden Pearl Overdrive but the OD does not work
« Reply #2 on: December 28, 2020, 02:24:41 PM »
First off, WELCOME TO THE FORUM!!

Second, did you notice that the battery at the PCB pad measures lower than pin 8 of the IC? It should be the same.

Looking at your voltages, pin 5 and 6 are shorted.
Your photos seem to show that too unless that's just the lighting.


edit:
Aw man you fixed it. Now what am I suppose to do?  :P
What was the issue?
« Last Edit: December 28, 2020, 02:26:52 PM by Kevin Mitchell »
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FuzzyFaceFuzz

Re: [fixed] Friedman Golden Pearl Overdrive but the OD does not work
« Reply #3 on: January 24, 2021, 07:20:46 AM »
First off, WELCOME TO THE FORUM!!

Second, did you notice that the battery at the PCB pad measures lower than pin 8 of the IC? It should be the same.

Looking at your voltages, pin 5 and 6 are shorted.
Your photos seem to show that too unless that's just the lighting.


edit:
Aw man you fixed it. Now what am I suppose to do?  :P
What was the issue?

Thanks Kevin! I fixed the solder bridge and it now sounds like i should.