Power problems. Doombutter (voltages added)

[matmosphere]

I just wired up a build and in having power issues. When I hit the switch the led blinks on and turns off immediately. No sound passes when the pedal is switched on. I'm guessing the two are related. I tested the power supply with a different pedal and can rule that out as the cause. I've double and triple checked the offboard wiring. Everything worked in the testing rig last night, so I'm pretty sure the problem is either the dc jack or the stomp switch. Anybody seen a similar problem before.

[BrianS]

I've had that happen before and I didn't have it grounded right.

[matmosphere]

Found the grounding issue. The led works now but still nothing in the sound department.

I think there might be an issue with the lm7805 My voltages for it are

1.66
0
8.74

Pt2399

1.66
.83
0
0
.81
.22
126m
1.58
0
0
.83
.83
.83
.83
.83
.83

[Jebus]

I think there might be an issue with the lm7805 My voltages for it are
1.66
0
8.74

Looks bad indeed. Either a bad regulator or something is pulling too much current in the circuit. Does the regulator heat up?

[matmosphere]

Save me Jebus, Thanks for the reply. Not getting hot at all. I know it's supposed to be a 5v regulator, does is deal with the extra voltage by heating up? I'll try to replace it tonight. Does this mean that I fried the pt2399 too? I hope that does it cause I can't wait to play with this thing.

[matmosphere]

is it possible to use a l7805cv instead of the lm78l05? is the cv just intended for more current?

[EBRAddict]

What electros are you using for filtering the voltage regulator, are they low ESR?

[m-Kresol]

as long as you check the pinout, every 7805 regulator should work. as far as I know, LM7805 are flipped 180° from the 78L05, but please check yourself!

[matmosphere]

Pulled out the old lm78 and socketed it and put a new one. My voltages are still off

78l05

4.15
0
8.62


Lm386

1.32
3.2
.3m
.2m
.57
.68
4.48
1.32


Pt2399
4.14
2.06
.5
.5
2.31
2.06
.571
.6
2.06
2.06
2.06
2.06
2.06
2.06
2.06
2.06

[m-Kresol]

your output voltage from your regulator seems a little low with 4.15, should be closer to 5V...
I cant find a schematic for it, please post the link for it

[matmosphere]

Thanks for taking a look. Here's the build doc. For some reason I think it's the most frustrating thing to have something work, box it, then have it not work.

I was looking at it trying to figure stuff out and I found a few things. The Lm78l05 gets VERY hot, and the pedal will pass a little sound (albeit sputtery inconsistent sounds) for a few seconds before the regulator gets too hot.

I don't understand a lot of what the passives do, but the next place I was going to look where the electrolytic caps on either side of the l78l05. I already replaced the 1n4001.

[m-Kresol]

I'm not really sure what's the cause of your power problem. Obviously something is pulling lot of current from the 7805. Please check for bridges and parts orientation again (if you haven't already) and maybe try another Pt2399...
You should also get your supply voltage (8.62V) on pin 6 of the LM386. you have 0.7V so no dice getting anything meaningful through the opamp.
The only things tied to the power rail are the opamp pin 6, the regulator, the smoothing electros C9 and C8 and the Pt2399, so check those first. might be a bad cap.

hope you get it sorted,
Felix

[Jebus]

As you can see from the schematic, the output of the regulator is only connected to the PT2399 and C8. Like Felix said, somethings pulling lot of current from the regulator (that's why its heating up and that's why the output of it isn't 5V). Sounds like a short to me. I had bit of similar problem with my Rangemaster build and it turned out there was gloop of solder shorting power rail to ground under a electrolytic capacitor.

Have you tried to measure resistance from the output of the regulator to ground?

[m-Kresol]

it might not be a short to gnd (that would pull the voltage down way more), but maybe to some other pin. Stll a good idea to check for bridges and the like

[matmosphere]

Thanks so much guys. Got it working now. Changed the caps, and socketed the ics. I'm pretty sure the problem was the lm386. Thank goodness for that new solder sucker my wife gave me.