Peavey Max 115 Bass Issue

[gtrplayr1976]

Hi folks,
Posting this for a friend I'm trying to help. He has a Peavey Max 115 Bass amp that has had a part explode in it. That's all I know right now. He says it's a cap ,but looking at the photo he sent the board where the part was is labeled L1 ? I have contacted Peavey for a schematic ,so I am waiting on that. I suspect the part next to it is the same ,and labeled L2 ? Anyone have any knowledge on these ,and exactly what that part might be ? Line filters ?

Thanks !

[The Dude]

It's a coil and I don't see how it could have "exploded" (it's just wire), though it may have gotten warm for some reason. I would clean things up and solder it back in. Without seeing a schematic or knowing what it's function is, there may be other problems. I see it's next to a woofer connector. Possibly it's a crossover coil? If that's the case, I'd make sure the amp is not putting out DC before hooking any speakers back up. If the coil got that warm, there are likely other problems.

[gtrplayr1976]

It's a coil and I don't see how it could have "exploded" (it's just wire), though it may have gotten warm for some reason. I would clean things up and solder it back in. Without seeing a schematic or knowing what it's function is, there may be other problems. I see it's next to a woofer connector. Possibly it's a crossover coil? If that's the case, I'd make sure the amp is not putting out DC before hooking any speakers back up. If the coil got that warm, there are likely other problems.

There is no soldering it back in. It's destroyed. He had just bought it used. Said it worked at the shop ,and when he got it home ,and plugged it in it exploded. I informed him there may be other problems. I'm waiting on Peavey to send me the schematic.

[Enzo]

Dude, check the photo, it is all cracked apart.

Definitely a coil. Too much current runs through it, it gets real hot and whatever it is potted in gives way. MAybe little pockets of air expanded too much.

Possibly the output of a class D amp circuit. FIltering out the HF crap on a digital signal.

In the absence of schematics, you can still check power transistors for shorts, and even power amp ICs.

[gtrplayr1976]

Dude, check the photo, it is all cracked apart.

Definitely a coil. Too much current runs through it, it gets real hot and whatever it is potted in gives way. MAybe little pockets of air expanded too much.

Possibly the output of a class D amp circuit. FIltering out the HF crap on a digital signal.

In the absence of schematics, you can still check power transistors for shorts, and even power amp ICs.

There are L1 ,and L2. L1 exploded. Hopefully I will get the schematic from Peavey ,and can share it here ?

[The Dude]

Dude, check the photo, it is all cracked apart......

I can't see that on my monitor for some reason. All I see is black, but obviously, if that's the case......

[Enzo]

More cracks than a Michigan highway.

[The Dude]

This is supposed to be the schematic, but I don't see those coils? Either I'm suffering some blindness today, or maybe yours is the series II or something?

http://adrsoundsense.co.uk/technical.../MAX%20115.pdf

[Enzo]

That is the old series from 10-15 years ago. Note the board art on his says NEW MAX 110/112/...

Note our schematic shows throughhole parts, while the board is SMT.

[gtrplayr1976]

The picture is part of power section with L1 ,and L2. The PDFs are the complete schematic.

[Jazz P Bass]

Yes, it is a Class D output section.

As Enzo stated, the inductors, L1 & L2, are used to remove the 'digital hash' and pass only the sine wave.

L1 is the one that is off the board.
22uh.
L2 is suspect as well.

Max_115-poweramp_2012 output.pdf

Not too sure what could have blown that inductor up.
My guess is that U5, TDA8954, is bad and passed Volts dc through it.

[gtrplayr1976]

Yes, it is a Class D output section.

As Enzo stated, the inductors, L1 & L2, are used to remove the 'digital hash' and pass only the sine wave.

L1 is the one that is off the board.
22uh.
L2 is suspect as well.

[ATTACH]47176[/ATTACH]

Not too sure what could have blown that inductor up.
My guess is that U5, TDA8954, is bad and passed Volts dc through it.

I was thinking the same that U5 may be bad as well. I can't seem to find it on the layout though? Found it on the secondary side.

[gtrplayr1976]

Apparently whoever he bought it from has made it right ,and given him another amp. Maybe someone else will be able to use these schematics. Thanks to all for the help !

[Enzo]

Yep, U5 is on the solder side.