Soldado / Active EQ from PCB Guitar Mania

[joelorigo]

I finished the Soldado & Active EQ combo from PCB Guitar Mania. The Treble pot acts more like a volume control with a really loud spot in the rotation. The Level control gets louder then quieter then louder again as it is rotated clockwise. In the attached video I have the Presence & Volume trimmers on the EQ board backed off a bit from full. (The Character trimmer was omitted & jumpered, and the 2 LEDs omitted with an added 1M resistor for one, as I didn't want/need any extra gain, based on advice from the Facebook PCB Guitar Mania group.)

 

[joelorigo]

C1 & C6 say 103K on them.

I am getting continuity from one lead of C1 and lug 3, and continuity from the other lead of C1 and ground

 

[PJS]

That all seems correct to me. Should have asked you to check Lug 3 to ground as well. The soldering looks really good though, so I doubt that is a problem. The only other thing I would get you to check is the value of your 2.2k resistors (there's 6 of them). In the photo they look as if they are 1.1 K (brown Brown Black Brown) instead of 2.2K (Red, red, black, brown). I suspect that is probably just the lighting of the photograph though. Resistor colours are bit hard to photograph well at times

 

[giovanni]

Somebody more familiar with capacitor codes should be able to confirm, but I do believe the code 4700 means 4.7nF.

 

[joelorigo]

The resistors do have red red black brown and all measure at about 2.2.

However I am NOT getting continuity between treble lug 3 and ground.

 

[PJS]

That is all as it should be. C1 is physically larger than the gap for it, so the leads will be sitting not quite where the board is deigned for them. Just check and make sure they are not touching anything. If I was troubleshooting this I would next replace C2 and see if that fixed it. If not I would replace C1.

 

[joelorigo]

Looking closely I can't see anything touching the leads for C1. I actually replaced it already because I had to pull the original to fit the trimmer.

As or replacing C2 I will do it but just curious about what you're thinking there. Sometimes there can be a bad cap? Should I try to reflow C1 & C2 first?

 

[PJS]

You could reflow first. The thing I am thinking is that the treble control really is (from what I can work out as a non-expert) C1, C2, and the treble pot. You tested the pot ages ago and it seems to be working. You have tested all the connections between the components. The only thing left is the actual caps. The character control may have some influence, but given that the symptoms haven't changed with those components there or not there I would assume it's not the issue here. It would be unusual for these caps to be bad from new, but we are running out of options - unless someone else can see something I can't

 

[joelorigo]

I reflowed C1 & C2. Didn't seem to make a difference. However, I'm not sure if this is different bu with all the trimmers and pots at about half way, there is no signal passing through. When I turn up the charakter pot the treble is acting like is has. I'm going to replace C2 now.

EDIT: Replacing C2 didn't do anything

 

[joelorigo]

I want to thank everyone of your help with this. The only thing I can think to add right now is that when it is plugged into a power supply one of the LED lights up, but not the both of them.

 

[PJS]

The only thing I can think of is to post on the DIY stompboxes forum. There are a lot of really good troubleshooters there.

 

[joelorigo]

Thank you. Happy holidays!

 

[joelorigo]

Update for anyone interested. After some awesome help form the DIY stompboxes forum, I can report that I have a Soldado with an EQ circuit. Not the PCB Guitar Mania Active EQ but the Tone TwEQ from Guitar PCB.