PL-400 DCP and WO light board

[AngrySailor]

Remove the outputs and check them.

Yep, I’ve got some replacements coming courtesy of grapplesaw also.

 

[laatsch55]

Ahhh.....

 

[laatsch55]

There's a 90% chance you have some blown semiconductors on the driver board. Most you can check in circuit...

 

[AngrySailor]

There's a 90% chance you have some blown semiconductors on the driver board. Most you can check in circuit...

I’m sure... prepare for lots of questions! I’m also not against a WO driver board if things are hurt bad.

 

[BibbieMok]

Hi... the problem with the PL-400 is at power up, a race condition exists, if you are unlucky (ie lose) the rails voltage
(75Vdc??) can be latched/clamped onto the spkr line = toasted spkrs. The pheonix site has a superior explaination. Once the amp has
survived power up it's fine, it generally wont toast the spkrs, unless you run it 24/7 in an oven at 200C

 

[AngrySailor]

Hi... the problem with the PL-400 is at power up, a race condition exists, if you are unlucky (ie lose) the rails voltage
(75Vdc??) can be latched/clamped onto the spkr line = toasted spkrs. The pheonix site has a superior explaination. Once the amp has
survived power up it's fine, it generally wont toast the spkrs, unless you run it 24/7 in an oven at 200C

The problem was “operator error”. No problems once I set up to turn things in innorioer order (power amp last).

 

[AngrySailor]

Plhhhpbbtttttttttbrrrrrrrrtttt

 

[laatsch55]

Hard to interpret that...

 

[AngrySailor]

Probably, just imagine the smell.

 

[laatsch55]

Ah...dead burnt motor smell??

 

[mlucitt]

Plhhhpbbtttttttttbrrrrrrrrtttt

The last sound a speaker makes when it gets hit with 75 VDC...

 

[J!m]

Similar to me after lunch at Taco Bell...

"Stink outside your Bum"

 

[wattsabundant]

I heard a 400II go down one time at an outdoor show. I was about 75 yards away form the stage. The roar coming out of the bass bins would make a Taco Bell trip sound like a whisper. My guess is the fault on the power supply caps due to the failure resulted in tons of 120Hz ripple going into the cabinet until the fuses blew.

The band had 3 x 400's on each side of the stage and the bass player had one on his rig. A few years later I was more or less on retainer for these guys. Their road crew was known as the wrecking crew for their propensity for dumb things like forgetting to close the rear door on the uhaul truck.