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Ampeg B410 HLF PCB melting fault?

J

Jason Keller

Guest
Sep 22, 2016
7
1
#1
Hi all,
This is my first post so hello and thanks for taking the time to read!

Ok, a few weeks ago (on day one of a European tour, no less) my bass amp failed again at sound check. I immediately pointed my finger at the head and started yelling profanities and threats at it. Turns out it was the cab. I tested all the speakers and they work fine and have the correct Ohmage readings on my multimeter (although the horn has never worked for some reason, even though it reads correctly on the multi meter, but that reason may transpire shortly)

I opened up the plate where the inputs and horn switch are, and lo and behold- melted terminal.

Clearly this is the reason why it wasn't working, but what would cause this to fail so unspectacularly?

Any ideas guys?

It's a pretty easy fix if all I have to replace is the terminal and do a bit more soldering, but if the cause is deeper routed I'd like to know what it is so I don't end up with more meltiness on my hands.

You'll notice that the blue wire and white wire have gotten so damn hot they've melted the terminal and the terminal legs which connect directly to the blue and white have actually melted off the solder and lifted from the board...

Any help greatly appreciated!

Best, Jason

AMPEG B410 HLF

AMPEG B410 HLF

AMPEG, B410, HLF
AMPEG B410 HLF

AMPEG B410 HLF

AMPEG, B410, HLF
AMPEG, B410 HLF

AMPEG, B410 HLF

#AMPEG, B410, HLF
 
#4
This can be a problem where the insulation displacement connection on the female (wire) side does not make good contact when the connector is assembled.

IMO, directly soldering is the only practical repair, unless you just replace the wire harness and the male connector.
 
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#5
agedhorse said:
This can be a problem where the insulation displacement connection on the female (wire) side does not make good contact when the connector is assembled.

IMO, directly soldering is the only practical repair, unless you just replace the wire harness and the male connector.
Click to expand...

Thanks! That's two for direct soldering then so far. I guess my main concern was that it could be a faulty resistor and that simply soldering the wires wouldn't get to the root of the problem, but directly soldering it seems to be the way to go.
 
#10
RoadRanger said:
Do yourself a favor and toss the connectors and solder the wires right in. I've seen way too many of that type connector burn up for no reason.
Click to expand...
There's always a reason.

A loose/poor connection has a higher resistance then the rest of the components in series. Current starts to get limited as the resistance goes up but----- heat at the poor connection causes the destruction and ultimate failure of the system.

Heat ie watts = I squared x R ; many house fires have been caused this way,
Especially ones wired with aluminum wire connected to copper screw terminals---
Thermal creepage takes place.

Eliminating the terminal and soldering the wire directly to the circuit board is a great remedy formth OP.
 
#13
Slevage said:
There's always a reason.

A loose/poor connection has a higher resistance then the rest of the components in series. Current starts to get limited as the resistance goes up but----- heat at the poor connection causes the destruction and ultimate failure of the system.

Heat ie watts = I squared x R ; many house fires have been caused this way,
Especially ones wired with aluminum wire connected to copper screw terminals---
Thermal creepage takes place.

Eliminating the terminal and soldering the wire directly to the circuit board is a great remedy formth OP.
Click to expand...

I'm also thinking this is why I constantly had to take my Hi Watt Custom 100 for repair, and why my Orange OB1-300 had been acting so weirdly.
 
#14
by my box the fuse explode someone knows what fuse i should buy to replace it?
 

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#15
It's a special bulb, the Ampeg part number is 49-205-01 which is 36V, 1.5A

Don't know where you are located, but here's the European link: Link Removed

They do not appear to be available in the US though.

You can safely use 2 of these wired in parallel, I used something like this on my older designs that used a similar horn driver:
Invalid Link Removed

It will take some skill to solder up the assembly though. I probably have a bag of pre-assembled OEM type around the shop if you run into a bind.
 
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#16
Slevage said:
There's always a reason.

A loose/poor connection has a higher resistance then the rest of the components in series. Current starts to get limited as the resistance goes up but----- heat at the poor connection causes the destruction and ultimate failure of the system.

Heat ie watts = I squared x R ; many house fires have been caused this way,
Especially ones wired with aluminum wire connected to copper screw terminals---
Thermal creepage takes place.

Eliminating the terminal and soldering the wire directly to the circuit board is a great remedy formth OP.
Click to expand...
^ ALL THIS.
And +1 for getting out the soldering iron.
 

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