Velodyne subwoofer no sound

[rudkinst]

Just bought a used Velodyne DEQ 8R BG. Can not get any sound out of it. It comes on, remote seems to control volume and settings, but no sound at all.
Woofer tests at 6.2 ohms.
Fuse is fine.
Looked inside and nothing is obviously blown but I didn't test anything.
Tried speaker and line level inputs from a couple of different sources. Nothing.
No hum or sound of any sort.

This is the second velo that I've tried like this. For a company with a good name I am shocked. And schematics seem non existent. I can't find anything online.

Anyone else have similar issues? Not sure what to try next and their website seemed like they will just shuttle me to a service centre and it's not worth it to me.

 

[Duane]

What do you have it connected to and where?

 

[swechsler]

This is the second velo that I've tried like this. For a company with a good name I am shocked. And schematics seem non existent. I can't find anything online..

Maybe that's why it was sold? What was the context of the other one you encountered?

At any rate, a lot of sub amps use output power ICs rather than discrete transistors, and like any other electronic component, they're subject to failure. Troubleshooting would consist of tracing the signal from the input jacks to the output section (or possibly the other direction) using an oscilloscope. If the amp has transistor outputs, you can check this video and see if it applies.

 

[rudkinst]

Maybe that's why it was sold? What was the context of the other one you encountered?

At any rate, a lot of sub amps use output power ICs rather than discrete transistors, and like any other electronic component, they're subject to failure. Troubleshooting would consist of tracing the signal from the input jacks to the output section (or possibly the other direction) using an oscilloscope. If the amp has transistor outputs, you can check this video and see if it applies.

Last one was slightly larger. Would only pass the signal through intermittently. Seller was very honest and he says it was working up until a few weeks ago but some novices often don't know when something is broken. He is still communicating with me.

I actually just bought an oscilloscope to learn on so maybe I'll use this as a test subject (following safety guidelines of course).

Great info, thanks. I'll look into your suggestions.

 

[rudkinst]

What do you have it connected to and where?

Tried my phone with a cable, my Yamaha home theatre subwoofer outputs line level and my Luxman 1050 using speaker inputs. All gave no sound.

 

[swechsler]

I actually just bought an oscilloscope to learn on so maybe I'll use this as a test subject (following safety guidelines of course).

If it turns out the amp uses output ICs instead of transistors, it will be helpful to have the pinout so you can check power, input and output signals directly at the chip. Most likely Googling the part number will find you a data sheet. Once you do those checks, you'll know right away if the problem is the IC or something else.

 

[rudkinst]

If it turns out the amp uses output ICs instead of transistors, it will be helpful to have the pinout so you can check power, input and output signals directly at the chip. Most likely Googling the part number will find you a data sheet. Once you do those checks, you'll know right away if the problem is the IC or something else.

Thanks. I have never tested an IC before so this will be a good learning chance.