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!

 

[Jeff C]

Yeah, I had it wrong in the first pic. Fixed that. The bypass works so a signal is getting from the input jack to the switch and back out to the output jack successfully. I ignorantly bought some funky looking jacks but they seem to work.

 

[carlinb17]

Those jacks are very common, why don’t we start with it out of the enclosure and get it working. So we have bypass, you haven’t installed your led yet so we don’t know if it’s getting power correct? It looks like d100 is backwards can you check the orientation. If it’s backwards it will not allow power through to the circuit.

 

[Jeff C]

I’ve not installed the led yet but can if that will help. Not sure what a d100 is. It’s not on the parts list. Sorry for my noob ignorance…..

 

[carlinb17]

It’s the 1n5817 diode just above the ic

 

[Mcknib]

It’s the 1n5817 diode just above the ic

Yep defo wrong way around

The silver line (cathode) should go to the right

 

[Jeff C]

Doh! Yes, that’s on the list and yes, I put the damned thing in backwards. I thought I was being pretty careful on all those polarity items. Damn. And double damn cuz that means I’m gonna have to take off the pot above it in a very ticklish de-soldering exercise. I don’t know what I did in previous lives but I’m sure paying for it now……. I‘ll get back to you guys if I am successful in this operation.

 

[Mcknib]

Just bend the pot outwards till you've enough room to get in

 

[BuddytheReow]

Just bend the pot outwards till you've enough room to get in

Just don’t bend it back and forth too much. It will weaken and eventually break like a paper clip although the paper clip breaks after only a few bends

 

[Jeff C]

Thanks! That helps a lot. now just to get that diode out gently…….

 

[Jeff C]

Well, I got the diode out (with the able assistance of my far more dexterous wife) and put it back in correctly. plugged it in but still have the same problem. I checked all the wiring connections with my multimeter and found that the ‘in‘ and ground on the PCB pads that connect to the switch are actually connected (the ones in the pic below, not that you guys need help with that!). I’m thinking that’s not a good thing, no? if so, I’m afraid that in changing switches I may have inadvertently established a solder connection there. So, if you tell me I‘m correct and there should be no connectivity there, I’ll remove the ‘in‘ connection (which looks the sloppiest….) and try to make a clean break between it and the ground……..and re-solder.

 

[carlinb17]

In bypass those will have connectivity due to the wiring on the foot switch when not in bypass it will isn't supposed to have connectivity

 

[Jeff C]

Tested again and of course you are right. On to making my audio probe……tomorrow. Too many good sports on today…….

 

[Jeff C]

Ok, made the probe and the probe works. I get signal from the input jack, the switch and the ‘in’ pad on the PCB. Read up about schematics and based on the Cobalt Drive schematic, I should then test at either R1 or C1 but I get nothing there…….. Suggestions?

 

[BuddytheReow]

R1 goes to ground so no need to probe that. Is there no signal on either side of C1?

 

[giovanni]

If you’re not getting signal on either sides of R1 you definitely have a problem because it’s also directly connected to the input…

 

[EGRENIER]

You should check connectivity between the in pad, R1 and C1... you may have cut the trace by accident.

 

[Jeff C]

So, best I can tell is the only signal I got is on C19, D5 and 6, and R20-23

 

[Jeff C]

No connectivity between the in pad and r1 or c1

 

[Jeff C]

But then how does it get to those other resistors, diodes, and capacitor?

 

[Jeff C]

Wait, no sorry, I do have connectivity to one side only of the r1 and c1 from the in pad