Any Love For The Digitech Valve FX?

[Sparker]

Schematic

[DrDckhol3]

I have the manual, am I missing something in it though? The only thing I see that resembles a schematic was that block diagram. I've scoured the web for the full schem to no (Avail :metal:)

[Sparker]

Plan is to check some PSU voltages first, then track a signal through in bypass mode. Back later (work   :(  )

[DrDckhol3]

Ok thanks, I'm in no hurry. Like I said before I'm a newb at electronics when it comes to identifying things and tracing the signal but I'm handy with the iron. So, with your eyes and my hand maybe we can get it going.  :thumb-up:

[Sparker]

Ok, so quick PSU check, you need a multimeter for this -

With the unit powered up, set mutlmeter to DC volts, measure the DC voltage across BR1 Pin1 & Pin2, doesn't matter which way around. This is between two two eCaps. BR1 P1 is marked + and P2 is on the same side, but to the left in the photo. Guide pic attached.

[MarshallJMP]

Next you can measure on pin 3 of U6,should be +12V,U7 pin 3 should be -12V and U1 pin 3 should be +5V.

If these are ok ,and from what i understand you have no sound in bypass either,it could be a bad opamp.If i look at the schematic it could be either U41 (LF353),U56 (LM833) or U32 (LF353).Or the switching circuit.(between bypass and effect).

[DrDckhol3]

Ok, so quick PSU check, you need a multimeter for this -

With the unit powered up, set mutlmeter to DC volts, measure the DC voltage across BR1 Pin1 & Pin2, doesn't matter which way around. This is between two two eCaps. BR1 P1 is marked + and P2 is on the same side, but to the left in the photo. Guide pic attached.

BR1 measured 32

[DrDckhol3]

Next you can measure on pin 3 of U6,should be +12V,U7 pin 3 should be -12V and U1 pin 3 should be +5V.

If these are ok ,and from what i understand you have no sound in bypass either,it could be a bad opamp.If i look at the schematic it could be either U41 (LF353),U56 (LM833) or U32 (LF353).Or the switching circuit.(between bypass and effect).

All pins measured correctly

[Sparker]

BR1 looks ok - was this with the tube pulled out?
Also, could you confirm that you don't get any sound in bypass mode with the tube pulled out.   :thumb-up:

[DrDckhol3]

The tube was in. Pulled the tube and no signal.

[Sparker]

I'm trying to attach a 1kHz test tone in a ZIP file, but can't seem to upload it. The whole reply just disappears!! I'll try and PM it to you then get back with some more details. Basically you play it into the input of the ValveFX from a music player/pc/phone etc, and using your multimeter set to AC, trace how far the signal gets through the ccts.

[DrDckhol3]

Right on

[Sparker]

Can't attach it in a PM either!!    :dunno:     Would be useful to have on the site though??   :thumb-up:

PM me an email address and I will send it there.

Cheers - Mike

[DrDckhol3]

Ok, I'm home and ready to trace the signal. What exactly am I looking for here? What components do I need to check?

[DrDckhol3]

I also forgot to ask....what setting to put my multimeter on on AC mode?