EH Screaming Bird (Audience!!!!) problems

[James P]

Hi guys

i've been given a 100% original EH Screaming Bird to fix that has a nasty problem. Whenever I engage the boost switch there is a loud pop and it then makes some very random crackly sounds.

Does anyone have any idea about how to go debugging it, as I don't want to go prodding around and making it worse.

Regards

James P  :?

[Eric H]

I assume this is the type that plugs directly into the amp or guitar, like my old LPB1? My bet is a bad ground connection. The plug and jack depend on a solid connection to the box for ground, and this becomes intermittent in time.

There might be a bad solder-joint in that rat's nest --you might just re-flow them all.

Replace any electrolytic caps, too (though I can't remember if there are any).
-Eric

[James P]

I assume this is the type that plugs directly into the amp or guitar, like my old LPB1?

Yes Eric, it's an inline treble booster although it has two jack sockets so you have to use two leads- sounds very harsh to me though!

My bet is a bad ground connection. The plug and jack depend on a solid connection to the box for ground, and this becomes intermittent in time.

I did think this initially. I'll clean up the connections.

There might be a bad solder-joint in that rat's nest --you might just re-flow them all.

I was going to resolder all the joints Eric as some look quite dull. It's a terrible wiring layout though. A right royal mess!!!!!!

Replace any electrolytic caps, too (though I can't remember if there are any).

No there aren't, only 2 caps and 4 resistors. A small parts count thank god, I don't  think it would have been made like this if there were any more parts involved.

Thanks for your help.

James P

[AL]

Try a pull-down resistor on the input to ground. This may eliminate the pop. Check the General Guitar Gadgets page or Fuzz Central. Most of the layouts/schems on those pages show a pull-down.

Crackling? I'll second what Eric said - clean it up. I had an LPB1 and the inside was a mess - clean up helped a good deal. Also, if it has one of those slide off/on switches you may want to check that and possibly replace.

AL

[spudulike]

This schem might be handy but its a really basic cct. Id fit a pull-down res anyway.
Schematic courtesy of AMZ (Jack O).

[James P]

Try a pull-down resistor on the input to ground. This may eliminate the pop. Check the General Guitar Gadgets page or Fuzz Central. Most of the layouts/schems on those pages show a pull-down.

Does it need to go before the input cap or after Al?

James P

[James P]

This schem might be handy but its a really basic cct. Id fit a pull-down res anyway.
Schematic courtesy of AMZ (Jack O).

Thanks Spudulike!

James P

[RickL]

If you haven't already, try cleaning the switch with some contact cleaner. Those slide switches can get corroded if they're not used regularly.

[AL]

The pull-down resistor goes before the input cap.

AL

[Ethan]

Might be some dc leaking through. Try changing the input and output caps. By the way, those screaming trees sound awesome when plugged into the BASS channel of non master marshall that is cranked.
-ethan