SOLVED Cobalt Drive problems…..SOLVED……..FINALLY!

[Jeff C]

New member here and also new to building pedals, as you will shortly see. I previously built a BYOC Reverb pedal kit successfully and it sounds great. I’ve also built from scratch a Strat, a Tele, a 59 LP, and an LP Junior. So, I wanted a blues driver pedal and thought I’d take a whack at the Cobalt Drive from PedalPCB. The directions are not as detailed as in a kit so I’ve had some difficulty. Clearly in over my head. I managed to procure the parts from the list (not without trial and error on my part) from Tayda. I mistakenly bought a switch without solder lugs so after consulting a patient, helpful friend, bought a daughter board and did my best to figure out how to marry the two - having no skills whatsoever in electronics. History major. I have managed to assemble it but I get nothing from it except static pops when I plug it in. Bypass doesn’t work. No idea what I’ve done wrong but I suspect it revolves around needing to do more with the daughter board on the switch. But what do I know? Here’s a couple of pics (the power jack is not there but I did connect it to test). And I haven’t installed the LED yet. Any and all suggestions are eagerly welcomed. You may recomemd I should just start over but I hope not….. Thank you!

 

[Joshhr]

Got it. Well, I guess I'll give it a shot. I hate removing solder (I have one of those suckers but it's always a trying experience. Meanwhile, I'll also take the audio probe route..... Tks!

Good de-soldering wick goes along way. I like chem-wik

 

[Jeff C]

I’ll have to give it a try!

 

[Jeff C]

Well, i put a bridge on the D100. No solder, it will adhere to the bridge but not the diode pins. . But I do get connectivity between both sides, and now when I test the voltage I get 1.2v on both sides of the diode.

 

[Jeff C]

 

[Jeff C]

And still audio at the q1 gate only.

 

[Jeff C]

But I do now get 1.24v to C100 now.

 

[Jeff C]

As well as to r101 and 102.

 

[Jeff C]

And c101

 

[Jeff C]

and pins 4 and 7 on the IC, although pin 7 shows less voltage. Could be cuz it’s a tight space to get to. I don’t know.

 

[Jeff C]

So, from the schematic, that seems to tell me that power is going to all the indicated points, although only at 1.2v almost.

 

[giovanni]

You should see close to 9V on either side of the diode. You probably have a short causing the voltage drop.

 

[Jeff C]

And r4 getting 1.2 and .8v, r2 getting .6 on both sides.

 

[giovanni]

I can’t quite tell where your bridge is?

 

[Jeff C]

On the D100 protective diode, as suggested by Mcknib above……..

 

[Jeff C]

You should see close to 9V on either side of the diode. You probably have a short causing the voltage drop.

I was getting 9v on one side only before I put the bridge in.

 

[Jeff C]

I’m thinking I must have messed up the D100 when I put it in backwards and then had to remove it and put it in correctly. Tried to be gentle…

 

[giovanni]

You should get about 9V on one side of the diode and about 0.6V less on the other. You are getting substantially less than that so either you have a short somewhere or the diode is busted (although in that case I would not expect a fixed 1.2V like you’re getting, but either floating voltage or 0).

 

[Jeff C]

stand by. My power jack is acting weird. I get 9v on the positive pin, but when I connect It to the wire leading to the PCB, it drops to 1.2v. (it didn’t do that before……) I’ve not soldered it because I have to install it in the enclosure before I can solder it and it will be impossible to troubleshoot this dang thing that way. I guess I‘ll solder it and see if I can get the 9v back……..and then just take the wires off and resolder if I ever get this thing to work……

 

[Jeff C]

Now completely befuddled. Soldered the jack. Still only get 1.2v! Tested i both at the jack and the PCB. The jack is ok because I tested it without the wires connected, prior to soldering. 9v. Then soldered the wires and tested it at the very place where I soldered on the wires and it’s now 1.2v. How can the jack test lower just because I soldered the wires to it? Aaaarrrggghh.

 

[giovanni]

Now completely befuddled. Soldered the jack. Still only get 1.2v! Tested i both at the jack and the PCB. The jack is ok because I tested it without the wires connected, prior to soldering. 9v. Then soldered the wires and tested it at the very place where I soldered on the wires and it’s now 1.2v. How can the jack test lower just because I soldered the wires to it? Aaaarrrggghh.

Hard to say. You may have a short somewhere between the power supply and your test point?