Blown part in PS of Fender Rumble 200 bass amp

[cowasaki]

Hello,

I can't find a schematic for this amp but located a blown component located where a connector attaches to the power supply/power amp board.  The part is labelled as FE101 and there are three of them in series with the three conductors of the input/output? lead.  The friend, who's amp this is, plugged another amp into the output of this one!!  And it stopped working.  He gave it to me and I checked by plugging the FX loop SEND to another amp and it worked so I presumed the power amp was at fault.  THEN when I took it apart and hooked it all up it worked.  I put it back together and it stopped working. I then took it apart again and saw this.  I think it was making an intermittent connection but the part FE101 is goosed.

FE?  Inductor of some sort?  It is in a SMD package with no markings.  There are two others FE100 & FE102.  The part FE101 measures as a 200 ohm resistor whilst FE100 measures under 1 ohm and as a 4.8uH @200KHz on the Peak meter and doesn't measure as a cap.

I can fix the board and replace the component but I can't identify it.

[free_electron]

ferrite bead. worst case : replace with a piece of wire...

[cowasaki]

ferrite bead. worst case : replace with a piece of wire...

This is exactly what I thought.....  just hate not having schematics for things I'm repairing and going in blind.

I'm emailed Fender but they usually take forever to reply

[geekyoyd]

I have just repaired a Rumble 200 with exactly the same fault.  Obviously those little HF blocking ferrite inductors are not up to the job of passing the required current.  The one that unsolders itself seems to be the 0V connection for the +/- 25 Volt supplies to the preamp circuits.  I replaced with a wired inductor that should suffice.

[CaptDon]

That would seem to indicate Ferrite Bead but it looks more like a resistor like maybe
a 1/8 watt .1 ohm SMD? All of the SMD ferrite devices I have dealt with have an
identifiable wire running through a tubular piece of ferrite. Our bass player has one
of the 200 Rumbles and the smaller one. It surely must have a neodymium speaker
because the unit is incredibly light!! My twin-12 guitar amp weighs A LOT more than
her 200 Rumble. I worked on her Ampeg Mosfet bass amp with blown finals. That
thing is a huge disappointment!! Those mosfets are biased to nearly self destruct
before you even play the first note!!! I tried to back the bias down but then when
the amp is cold I get zero crossing distortion which sucks!! I told her "Play it hard
until it blows up again and next time I'll add a fan. So far it still works. I used massively
over rated FETs when I fixed it.

[geekyoyd]

Thanks for the information.  I have had the same problem with a Fender Rumble 200, a burnt out ferrite inductor.  When it blew, it damaged the tiny PCB track so I had to put the new (wired) ferrite on the back side of the PCB.  Worked in the end.  Designwise:  FENDER, WHAT THE BLOODY HELL WERE YOU THINKING!!

Electronic engineering design hit a high somewhere in the 80s and 90s with solid fibreglass double sided PCBs and tracks that are stuck down properly.  Since then it has regressed into shite.

[gamalot]

That would seem to indicate Ferrite Bead but it looks more like a resistor like maybe
a 1/8 watt .1 ohm SMD? All of the SMD ferrite devices I have dealt with have an
identifiable wire running through a tubular piece of ferrite. Our bass player has one
of the 200 Rumbles and the smaller one. It surely must have a neodymium speaker
because the unit is incredibly light!! My twin-12 guitar amp weighs A LOT more than
her 200 Rumble. I worked on her Ampeg Mosfet bass amp with blown finals. That
thing is a huge disappointment!! Those mosfets are biased to nearly self destruct
before you even play the first note!!! I tried to back the bias down but then when
the amp is cold I get zero crossing distortion which sucks!! I told her "Play it hard
until it blows up again and next time I'll add a fan. So far it still works. I used massively
over rated FETs when I fixed it.

They are clearly ferrite beads, pay attention to the designators next to them (FE100, FE101).

[samholloway]

hi mate, can you share what that component value was ? I have the same issue and what to get one of those inductor coils but not sure what to order.?

cheers

[samholloway]

any idea what value it is?

[samholloway]

I removed the old ferrite and replcaed with a small coated wire. Works fine now. lol

[pienari]

 Look like they have redesigned board.
https://shop.icepoweraudio.com/wp-content/uploads/2023/02/ICEpower50ASX2_Datasheet_1_9.pdf