Crossfire VR4000D blown help?

[petercourt]

(posted original in wrong section)
Holla!
I purchased a crossfire VR4000D used, I went to the guys house to test and pick it up, When I got there to test it he said he could only power it up and could not shoe output due to no source unit. (now I know why)

Anyway he powered it up, Power light lit up blue, Internal fan started spinning, and I also heard the relay inside click after 3~4 seconds. So I packed the amp and brought it home.

Next day I put it on the bench to test its output. And just my luck nothing!. Power light was on, fan was spinning and relay clicked. So I opened the amp up and found some very nasty burnt mess.

I took a few pics to see if anyone knows what part exactly had blown as its hard to see as its all so burnt.

 

[Perry Babin]

Post a photo of the transformer on the other side of the amp from the same angle.

Clean up the mess with cotton swabs and alcohol or acetone (preferred) to see how bad the damage really is.

 

[petercourt]

Post a photo of the transformer on the other side of the amp from the same angle.

Clean up the mess with cotton swabs and alcohol or acetone (preferred) to see how bad the damage really is.

Hi Perry. I opened the amplifier back up and found more disturbing news. It appeares as if all the power supply mosfets have blown, However the amplifier still poweres up just fine. I took some horrendous pictures horrible lighting.
Would have made more sence if the output FETS let go.

I did not see this earlier. I'd have to drag the circut board out of the chassis to get a better look but I just don't have the room this amp is massave!

If all the FETS have gone, plus whatever else it may not be a viable option to attempt repair. May just sell it as parts.

 

[Perry Babin]

You'll have to decide what's best for you. If you think you may want to repair it, check the output FETs to see if they're shorted.

 

[petercourt]

You'll have to decide what's best for you. If you think you may want to repair it, check the output FETs to see if they're shorted.

Hi Perry. I blew up my old multimeter, brought a new one yesterday, testes all output FETS and none are shorted, all checked OK. However every single power FET are shorted. How can it still power up in this condition?

 

[Perry Babin]

What qualifies as powering up?

It's not likely producing any supply voltages.

 

[petercourt]

What qualifies as powering up?

It's not likely producing any supply voltages.

Like I said earlier. Apply power, protect light illuminates for a second then blue power light comes on, internal fan powers up and also you can hear the relay inside click. It poures up absolutely as normal just has no output. Which is why I was surprised to see all output FETS intact and all power supply FETS blown along with that blue melted thing. Makes no sense.

 

[Perry Babin]

All of the LEDs, fans and relays are likely on the 12v supply line. The high voltage rails and preamp supply are likely completely out.