Gravitation reverb

[steviejr92]

Hi guys I’m new to pedal building and this is my 3rd build the gravitation reverb. I had populated the board and I wired it to jacks and stomp switch I had bypass when it’s turned off but when engaged I get no sound even though the led light turns on. Which leads me to believe the problem is on the circuit board yet I have looked at others boards and mine doesn’t look any different I don’t if my parts are low quality if that a thing but all of my polarities on my electrolytic capacitors are right both my ic chips are on correctly, I do use bojack resistors from a kit but I don’t know if that will affect anything I did notice the legs are a bit thinner but others other than that they’re all the right values. I checked my pots and they’re on correctly and I do have the right belton reverb chip soldered directly the only the thing different I could notice was the voltage regulator the pub calls for L78L05 but I have LM78L05ACZ I don’t know if that’s it I read somewhere that the pin out might be different but I’ve gotten 2 different answers yes and no lol. I’m lead to believe this is the problem. Can anyone help me out here I’ve ordered a 2nd board and reverb chip since I feel like the parts could be duds……oh and I forgot to mention because of that confusion about the voltage regulator I’ve removed and tried backwards and the same thing and now I e ruined the eyelets where it’s needs to go idk if it’s salvageable but I’ll be posting pics please help lol

 

[Robert]

Yep.

Did you confirm you have continuity between pin 8 of the two opamps?

 

[steviejr92]

Thank you so much scratch that last post I’ve made up my mind I will just wait and re use the opamps

 

[steviejr92]

yes I get continuity between pins 8 on both opamps

 

[steviejr92]

Sorry man I’m like all over the place if I can get this thing going then let’s do it! Lol

 

[Robert]

Connect a wire from the right end of the 1N5817 diode (stripe) to pin 8 of the top opamp.

It'll be easiest if you do it on the bottom of the board.

We need to make a couple measurements before you power it up.

 

[steviejr92]

Any tips on how to get underneath the module I don’t have a solder gun to heat all the pins to pull it out all at once that was my problem with the regulator lol

 

[Robert]

Yeah don't try that. Hang on.

 

[steviejr92]

No problem!

 

[Robert]

OK, not being able to get under the brick is going to complicate things....

We can still do it if you're set on fixing it, but it's going to involve several jumper wires. Especially when it comes time to reinstall that regulator.

If you want to do it for the point of doing it, we certainly can.

 

[Robert]

I wouldn't recommend trying to remove the brick though.. I have a wide blade soldering iron I use for that sort of job, it'll almost certainly take pads and traces out with it if you try with a regular iron.

 

[steviejr92]

Ok so I’m all ears to try to get this thing working if worst comes to worst I have another on the way. So what step one? Lol

 

[Robert]

OK, connect a wire from the Red point to either one of the Green points, whichever green point is easier for you to get to.

The top one will involve bending the pot out of the way, the bottom one might be too close to the brick and you don't want to melt it.

 

[Robert]

After you do that check for continuity from the right end of the diode to pin 8 of both opamps.

You should have continuity.


Then make sure you DON'T have continuity from the right end of the diode to ground.

You do not want continuity there.


If both of those check good you can plug it in and test, you should have a clean signal (no reverb yet)

 

[mybud]

However, since you do have a new PCB coming, if you'd rather wait and rebuild you can do that as well.

And maybe socket the voltage regulator for next time if you didn’t.

 

[steviejr92]

So I have continuity on pin 8 on both opamps from right side of diode not the left

 

[steviejr92]

Have not plugged it up to see if I get clean tone gimme sec to confirm

 

[Robert]

That's correct.

Check to see if you have a clean signal with the pedal on now.

 

[steviejr92]

Ok so I plugged everything up again I get bypass but nothing when engaged light still turns on

 

[steviejr92]

And maybe socket the voltage regulator for next time if you didn’t.

I will definitely think of that next I didn’t even know they made sockets for voltage regulators lol

 

[Robert]

Hmm.. okay, so there might be some other broken traces.

This one might turn into a can of worms at this point. One or two patched traces is no big deal but you don't want wires going everywhere looking like spaghetti.