Wanted: Behringer BSY600 Bass Synthesizer schematic

[Steve Conner]

Great, glad to hear it worked Here at MEF we never leave a man behind, even if his name is Behringer...

Re the current draw: When you're dealing with gear that has switched-mode supplies in it, remember that as the supply voltage goes down, the current draw goes up. If you tried with a fresh battery, it would probably draw less current.

Also, the reverse polarity protection circuit we discussed isn't 100% effective because the transistor can suffer reverse breakdown (at about 7-8V for a 2N3906.) I imagine this is why you still saw some leakage current on your simulation, and also why Behringer felt the need to back it up with a reverse diode on the input. Or maybe it's a self-destruct circuit to help them sell more pedals...

[beerbunny]

Great, glad to hear it worked Here at MEF we never leave a man behind, even if his name is Behringer...

That's good to know; sometimes you need a little help (Oh, how I miss being able to discuss stuff with my ex-colleagues).

Regarding the current; it did occur to me that it would go up as the voltage dropped because of the switched-mode psu, but I wasn't willing to waste another PP3 on this job (the battery I was using was new when I started looking at this pedal); I'm not getting paid for this. Also, I didn't want to connect it to my psu; with my luck I'd connect it the wrong way round.

Regarding your comment on the usefulness of this reverse protection cct; it's self-evidently not up to much, both the diode and the transistor were blown.

While I think of it, the reason I didn't consider a PNP transistor was that all the devices I found on the internet that were marked '2G' were NPN. Well, that's my excuse, and I'm sticking to it.

Anyhoo, thanks again for all your help,

John

[Enzo]

2G or not 2G, that is the question.

[beerbunny]

2G or not 2G, that is the question.

John

[Sk10]

Hey Guys,

I have the same problem with my BSY600
So if I'm correct, the solution is to replace the faulty transistor with a 2n3906?

Thx!

[Acuosuo]

responses very

this is bump!

[MarkusBass]

Hey Guys,

I have the same problem with my BSY600
So if I'm correct, the solution is to replace the faulty transistor with a 2n3906?
Thx!

I would start searching here: 2G SMD Code Search
2N3906 has different marking (2A as far as I rememeber). Also the idea with the circuit simulation in TL Spice is very good. At least the power supply part is very simple so it shouldn't be to difficult to draw the schematic and simulate it.

Mark

[altered]

Does anyone know what the unused 5pin IDC connector is along the top edge.? (next the blue LED)