Active Wiring Questions

[stewblack]

Hi, I am trying to restore a bass to its original glory. 

I have the pickguard with the original circuitry and the previous owner labelled the wiring so I'm reasonably confident that I can connect it all up. 

Except for the battery. There is just an void where the battery sits. No wiring nothing. 

I am fine getting the clip, 9v connection and wires. But where in tarnation do I connect them? 

[Hellzero]

I doubt that this circuit still works as at least 3 components burned.

That said, the +9 Volts input is in the low middle part bear the white wire of your printed circuit. The black one being the ground.

[stewblack]

1 hour ago, Hellzero said:

doubt that this circuit still works as at least 3 components burned.

I was told it worked before it came to me so I sincerely hope that's not the case

 

[bloke_zero]

Looks like you'd need to resolder to the 9V in just down from the white 'Out' wire. Is it clipped off there?  You might need to desolder if so - which can be a bit tricky. I'd expect there to be a ground/- in as well near the 9V in.  it looks like there are 3 inlets to the right of the white out wire? Hard to tell from the picture. I'm sure better brains than mine will be along to offer some wisdom.

[Woodinblack]

As people say, the +9V from the battery is in the middle on the left in that picture, the black wire from the battery goes to the middle pin of the jack socket, and the earth pin of the socket goes.. somewhere? What is that black wire coming out?

[stewblack]

19 minutes ago, bloke_zero said:

Looks like you'd need to resolder to the 9V in just down from the white 'Out' wire. Is it clipped off there?  You might need to desolder if so - which can be a bit tricky. I'd expect there to be a ground/- in as well near the 9V in.  it looks like there are 3 inlets to the right of the white out wire? Hard to tell from the picture. I'm sure better brains than mine will be along to offer some wisdom.

Thank you. I will be letting someone else do it I think. 

paging @basstone is this within your skill set? 

[stewblack]

Actually don't worry I can clearly see where the 9v positive comes in and connects, the ground is obviously going to ground with all the other grounds!

Still wondering which of the components are blown...

[Hellzero]

The protective diode is burned. This means that somebody tried very hard to reverse the polarity.

[Hellzero]

A second hand one just appeared today. Check your emails. 😉

[stewblack]

5 hours ago, Hellzero said:

A second hand one just appeared today. Check your emails. 😉

I'm trying to fit this plate which came with the bass (previous owner converted it to passive) because I have a buyer interested in it. I've already set a very low price cannot spend any more on this.

[stewblack]

16 hours ago, Hellzero said:

The protective diode is burned. This means that somebody tried very hard to reverse the polarity.

So if I put a multimeter either side of the diode there should be no reading (assuming it has blown)

[Hellzero]

Read this to understand how to check the diode : How to test a Diode with a Multimeter (electronicspost.com)

Out of curiosity, what's the brand of your bass ?

[Woodinblack]

2 hours ago, stewblack said:

So if I put a multimeter either side of the diode there should be no reading (assuming it has blown)

It can be burned and unblown

[Guest]

Hellzero, out of curiosity how are you able to see this? Where in the picture above are you looking. The photo isn’t super sharp so what may look like a burned component may be a shadow or something else entirely. To my non-expert eye I cannot see what you’re seeing.

[Woodinblack]

1 hour ago, FDC484950 said:

Hellzero, out of curiosity how are you able to see this? Where in the picture above are you looking.

I must admit that I don't see any burning at all, but I didn't look when someone said there was.

This is protection diode burning:

Edited November 30, 2020 by Woodinblack

[stewblack]

5 hours ago, Hellzero said:

Read this to understand how to check the diode : How to test a Diode with a Multimeter (electronicspost.com)

Out of curiosity, what's the brand of your bass ?

Fender

 

[stewblack]

I have connected it all back together and apart from a couple of scratchy pots everything appears to work. I can certainly achieve recognisable bass notes from it. 

However... all is not well. It buzzes. Loudly. But only when I touch the controls. No other metal parts buzz when touched. 

Any ideas? 

[Woodinblack]

Yes, you need to earth the controls. One big black* wire going from every control to the earth point of the circuit, or the body connection of the jack socket (which is not the bit connected to the battery, but the 0v of the circuit

* other colours are available.

Edited December 3, 2020 by Woodinblack

[stewblack]

Fixed, thank you!