Crate blue voodoo.

[catstrat]

Hello everyone. I don't usually visit this site unless i'm really baffled about something. I have a CRate Blue Voodoo 120 watt amp the is not switching channels. The footswitch and the button on the front panel doesn't work. It's an internal issue but the schematic i have isn't matching up with the circuit so any help would be appreciated. Thanks.

[Jazz P Bass]

Well which schematic do you have?

Here is a cropped BV120H footswitch circuit.

[PeanutNore]

I found with my BV120 that if you have the wrong type of footswitch connected neither the footswitch nor the front panel button will switch the channel. Does your front panel button work with the footswitch unplugged? If so, the footswitch jack might be dirty and in need of cleaning, or shorted and in need of replacement.

[catstrat]

Hello everyone. It's definitely a circuit problem because it isn't switching by the panel switch or the footswitch. Thanks for the suggestion. Thanks to you Jazz p for the schematic. I'll compare it to what i have and get back to you.

[Jazz P Bass]

You may have a bad footswitch jack Tip connection to the pcb if neither works.
Start with the FtSw itself.
Does engaging the switch connect the Tip to the Sleeve?

After that is proven good, the first item that I would check is D4.
Is it shorted?
If not, the top should go to ground when either the front or the foot switch is engaged.
If it doesn't, then the jack needs attention.

[catstrat]

Thanks everyone for the help. It was a shorted ZD4 zener diode. It was 3.3 volt zener and the closest replacement i had was a 3.9 volt but it works. I'm happy,the customers happy and thanks again everybody.

[Jazz P Bass]

Woohoo!
Somebody wacked that a good one, huh?

1/4" jacks are great, until you have 4 or 5 on the back panel, on stage, in the dark, where the heck does this go, had a few........

[Dave H]

1/4" jacks are great, until...

Someone uses instrument cable for speaker cable. Our bass player did it once. I could see the smoke from the other side of the stage. I thought his amp was on fire.

[Jazz P Bass]

The current handling capability goes down the more strands that are used.
If you take a typical instrument cable with 20 ga wire/ 32 strands, it is good for maybe 3 amps.
(there are cables made with less strands & lower gages)
If the bass player was thumping away at 300 watts/ 8 ohms, that comes to roughly 6 amps.

Yep, that will smoke it.

[TomCarlos]

Just an FYI... I too have a Crate Blue Voodoo BV120 .... Here is the schematic for mine (and photo of the amp). Tom