Need help with repair on Rumble 200

[Mike Mackey]

I've had this amp since 201 . Played great every day till today. It started smelling of burnt electrical and then no spund. I turn it on and hear a pop with no sound. The pop resemble if you had a cable plugged in with no bass and touched the output end. That kind of noise. I removed the electronics and seen a slightly burned connector going to the board as pictured in the thread. I'm guessing it's a fuse. Is there anything I can do with this?

 

[Mike Mackey]

Sorry about the typos on my phone. I had the amp since 2014. Bought it brand new. I'd really like to get it back working cause it's a great practice amp and light weight.

 

[agedhorse]

That's an inductor. The power module is not designed for field service, it must be replaced.

When that part fails, there's often other damage so you don't want to replace the module without insuring that any additional damage is identified and repaired.

How much experience and test equipment do you have?

 

[Mike Mackey]

I fixed military equipment and automotive for about 30 years. Can read basic electrical schematics. Have a fluke multimeter and soldering iron. So probably more than an average Joe but not anything close to a technician. I think a friend plugged something into the ext speaker port and caused it to fry. Probably due to a ohm difference.

 

[agedhorse]

The most common cause of this type of failure (not necessarily this particular failure) is when the bridged speaker output (iirc that's a stereo module operated in BTL mode) is connected to something other than the speaker that's ground referenced. The shell of a signal cable with the other end connected to the amp (like an aux input or effects loop cable) is a common cause.

It almost always damages the module because a lot of current can now flow where it's not intended.

 

[Mike Mackey]

So would you say I should hang it up with this combo? Or can that board be replaced fairly easily and somewhat inexpensively? I see them for sale for about 135 buck . The amp is 4 to 5 hundred new.

 

[Mike Mackey]

I have it out now, as seen in the pic

 

[agedhorse]

They are easily repaired IME, but I would certainly want to verify that there is no additional damage before installing a new module.

 

[Mike Mackey]

So what would you do if you were me? Just scrap it?

 

[agedhorse]

I would find a Fender authorized service tech who is familiar with these amps. The cost of repair including the module (even if there is additional damage) should be less than $200 if the guy is being honest/fair.

You could roll the dice and replace the module, but if there is other damage you could be in the same place you are right now plus the cost of the module.

 

[BassmanPaul]

In my mind it's Tech Time!!

 

[rtslinger]

Qualified amp repair guy, if you are second guessing own skills.

 

[Mike Mackey]

Agedhorse, you seen quite verses with technical specs. I'm going to take a stab at replacing the icepower boar . I just want to make sure I find the correct one. I reached out to fender and obtained a schematic of the 200 Watt amp. Apparantly there was a V2 (150w) and a newer V3 (200w) and both use the same board. The exact module I am honing in on is an Icepower 50ASX2BTL class d audio amplifier with power supply module 1 x 170 watt. It says it drives any speaker load from 2 ohms and up. I believe my ext speaker jack said 8 ohms. Do these specs look right to you for my specific amp? It's only a $115 dart to throw but I'm really attached to that amp as my practice one. I also seen there's two modules. One was an SE and one a BTL. I'm guessing I need the latter.

 

[Mike Mackey]

Agedhorse, you seen quite verses with technical specs. I'm going to take a stab at replacing the icepower boar . I just want to make sure I find the correct one. I reached out to fender and obtained a schematic of the 200 Watt amp. Apparantly there was a V2 (150w) and a newer V3 (200w) and both use the same board. The exact module I am honing in on is an Icepower 50ASX2BTL class d audio amplifier with power supply module 1 x 170 watt. It says it drives any speaker load from 2 ohms and up. I believe my ext speaker jack said 8 ohms. Do these specs look right to you for my specific amp? It's only a $115 dart to throw but I'm really attached to that amp as my practice one. I also seen there's two modules. One was an SE and one a BTL. I'm guessing I need the latter.

 

[Mike Mackey]

Sorry in advance for the typos. Using my phone

 

[agedhorse]

It's the BTL version but it will not drive a 2 ohm load in the real world as configured.

 

[Mike Mackey]

Ok but it should work ok in my combo though? I appreciate the help. I'm learning quickly with all this.

 

[agedhorse]

Ok but it should work ok in my combo though? I appreciate the help. I'm learning quickly with all this.

Yes, be very careful handling it, there are surface mount parts on the top AND bottom of the module. Also, be 100% sure that the power is properly configured BEFORE powering up.

 

[MischaMischer]

Hi, what did you do finally? I am having the same isue right now... I did repair several Class-D Amps and if you hear a PLOPP when switching on, that indicates one of the End Mosfets is short circuited. Unfortunately the Class-D amps have a lot of back-coupling so a damaged MOS may burn your Power Supply (SMPS) as well. So better use it as spare parts or change the complete module. Changing only the MOS requires a better knowledge of the circuit -> a schematic diagram and I did not find any.

 

[agedhorse]

The OP’s damage is not limited to MOSFETS.