Kenwood Power Amplifier (Basic M2A) - Help Needed

[Flamedemonzs]

Hello, this is my first post on this site. I will try to be as specific as I can. I recently acquired a Kenwood Power Amplifier (Basic M2A) from someone I knew. When I first plugged it in there was no power. I decided to opened it up to check what might be the problem and I saw that both the fuses were blown and the power supply wire was disconnected from the main board. So I replaced the fuses and plugged in the power supply wire. Powered it on and pop. Smoke started to come from the amplifier. Checked the fuses and they were still fine.

2 days have passed and I decide to take a look again. Now I try lowering the amps on the fuses to see if they will blow. This time the amplifier does power on, but again smoke. But this time I notice two resistors (image with this post) get really hot. Like you can see them turn red orange. Smoke stops. I suspect the resistors are fired. Now the power indicator light is blinking.

Any help would be appreciated. I know how to solder and use a multimeter. I want to fix it instead of recycling it

 

[cademan]

Welcome! First off, are you sure the wire is a power supply wire and connected to the right place?

2nd, if you look at where those smoking resistors are connected to, they are most likely connected to some transistors which are probably shorted. Check all transistors for shorts that are associated with any burnt resistor.

3rd, fuses should always be replaced with the exact same current rating. Voltage rating can be higher but not lower. If any blown fuse is blackened, this indicates a short and the culprit needs to be found and remedied before going any further. Usually (but not always) the output transistors are first suspect.

Blinking indicator light means that there is a problem and is probably in protection mode.

4th, might as well check the output transistors for shorts as these are usually the cause of a lot of problems when they go bad or short. In my experience, most output transistors will last forever as long as they are not abused meaning switching speaker wires and accidentally shorting them when the unit is powered up, cranking the unit into clipping and distortion for extended periods of time, improper cooling of the output transistors (blocking or no air circulation), and/or using 4Ω speakers when unit specifically says not to use speakers below 8Ω's.

Hope some of this is helpful!