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I was working with an Alpine 2 channel car amp and trying to bridge outputs to a dual voice coil subwoofer. 4 ohms x2
Initially I got some output putting each coil on Left and Right but that's not a proper hookup. next step I paralleled the VC to obtain 2 ohms impedance and placed it across (what I thought were) the outer two (Left - and R +) but maybe I did it wrong, could have bridged any two terminals for a short time. (nothing was on for more than a minute or two in any config).

In any case, I don't get any output now and nothing inside looks fried. I'm using a digital monobloc amp for the sub now and that works so the speaker is unharmed.

https://pdf.crutchfieldonline.com/Image ... RPF240.PDF

Found and added this to post
https://www.manualslib.com/manual/95472 ... e=8#manual

Mostly I'm just asking if anyone Knows that this is a known way to blow an amp.

Hi. Did you connect it this way ? Being the speaker symbols actually coils of the same subwoofer ? You are a skilled non-beginner... Let's fix it. Power supply rails fine, right ?
Warm up the scope...

I agree it is repairable, I need to take it out of the car and put together a bench setup with some signal sources first. I've had these sitting on a shelf for nearly a decade and now I am completely refurbishing my 93 Explorer and these fit well under the seats. (they were insurance replacements for 2 that were stolen). That was a fun project now basically So I need to take a closer look at the whole setup, since there seems to be no output at all, not scratchy or low. I can use a scope but probably start with AC RMS measurements.done.

I studied the schematic some more, I don't think one can blow the output with an incorrect bridged hookup, I would have either one channel or ground on both sides or reverse phase because the negative speaker terminals are all common ground.



Can't see any of the ICs when I look inside, they must be on the hidden backside of the PCB and need some disassembly. The service manual does not show that side of the PCB either. its a mystery until I tear it down but not until after basic diagnostics.

Hate to be the one to say this, but, most of those amps have a fuse. Is it good?

Addendum
I see the main fuse up by the transformer. I'm sure you checked it, but gotta rule it out.

Next question.

You don't have the MUTE activated somehow, do you?

Not the fuse. Initially I didn't check because the pilot lamp was turning on and off with the remote switch as expected but than I worried there might be a current path to the LED without power but although there is, the resistance is too high to light the lamp. I checked it today and was good. Mute and remote are basically the same thing external to the amp.

your outputs are the 4 big mosfets on the left, on the right is your power mosfets and diodes for the power supply.
is there not a PROTECT led lit up ?

here is how you properly bridge a car amp.. left and right input as normal.. then follow this...

https://www.wikihow.com/Bridge-an-Amplifier

what is the model and name of the amp you have ?