fusion fp-1002 problems

[leftys4js]

hello ive got a problem with my amp not sure if needed but heres the specs on it.
Fusion FP-1002

2 Channel Amplifier

Fantastic amp for running two average 12" subs or one really powerfull one.

2 Ohm Stable MOSFET Amplifier Design
FUSION Regulated Amplifier Technology (F.R.A.T)
FUSION Intercooled Semi-conductor Technology (F.I.S.T)
FUTRANZ Efficient Heat Sink Transfer Technology
Gold Plated 4 gauge Power and Ground Connections
Gold Plated Audio Input and Output Connections
Gold Plated RCA Output for Multi-purpose installations
Compatible with FUSION bass control remote

Product Specifications

Bandwidth 10Hz - 40kHz
Signal to Noise >95dB
Fuse Rating 2 x 25A
Separation >60dB
Input Sensitivity 300mV-8V
LP Variable Crossover 40 Hz - 160Hz @ 12 dB / octave
HP Variable Crossover 40 Hz - 600Hz @ 12 dB / octave
Variable Bass Boost 0dB + - 18dB Gain @ 45 Hz
Variable Sub Sonic Filter 20 Hz - 55Hz @ 18dB / octave
Input Impedance 20K
Damping Factor >200
T.H.D 0.05%
Dimensions D 57.5mm L 290mm H 220mm

12.6 Volt Power Output Specifications
95 WRMS per Channel @ 4 Ohms and 1% THD+N
140 WRMS per Channel @ 2 Ohms and 1% THD+N
300 WRMS Bridged Channels @ 4 Ohms and 1% THD+N

14.4 Volt Power Output Specifications
130 WRMS per Channel @ 4 Ohms and 1% THD+N
210 WRMS per Channel @ 2 Ohms and 1% THD+N
425 WRMS Bridged Channels @ 4 Ohms and 1% THD+N

being new to electronic repair id like to try myself but no clue where to start. or what to look at i did pull it apart but no clue what i was seeing didnt see any burnt or black though

the proble is it worked great for about 1 1/2 years and now it powers on ok lights green and stays green when 1st turned on it works ok but after a few minutes all you can hear is a solid bass thumping(and out of sync with music being played) noise if that makes since.volume stays the same whether you turn it down or up...and it feels warm to the touch..i have 2 cars with amps and subs so i removed it and hooked it to the other and it does the same thing..
any advice would be appreciated thanks

[spooney]

can you get us some pics of the amp ? inside and out(outside pics aren't necessary but I like to see the heatsinks )

[Perry Babin]

It sounds like you have an open shield ground connection. Measure the resistance from the RCA shield on the RCA input jacks to the non-bridging speaker terminals. Do you read ~0 ohms?

Disconnect the RCA cables from the RCA jacks before checking the resistance.

[leftys4js]

sure i will dig it out of the basement and snap some shots for you as soon as i can

perry sorry as stated im kind of a noob when it comes to electronics how do i do that thanks

[spooney]

I think I repaired one of these same amps a while back. My buddy has been running it for quite a while now and he seems to like it.

[spooney]

Now that I look it up the amp I see it isn't the same. Looks to be a smaller maybe newer version on my friends amp. I did however stumble across a free service manual for this amp. I hope it can help you out some : FUSION FP1002(Car Amplifier)

[Perry Babin]

Do you have a multimeter?

[leftys4js]

no i dont i will get one though

[leftys4js]

ok got it out and took a few shots of the insides if you need different just let me know

SDC10289.jpg

SDC10291.jpg

SDC10292.jpg

SDC10286.jpg

[Perry Babin]

You need to check the output transistors (those near the large white transistors).

When checking transistors (bipolar or FET) with your meter set to ohms, you should not read anything near 0 ohms when the probes are touched to the terminals of any individual transistor in any configuration. If any are shorted (~0 ohms between any 2 legs of any individual transistor), they will likely be shorted from leg 2 to leg 3 but you should check 1-2, 1-3 and 2-3.

Check all of the transistors individually. If it appears that several are shorted, you'll need to remove all that appear shorted from the board and check them individually. In the case of the output transistors, if you find only 1 shorted in a group of parallel-connected transistors, you can reinstall the ones that are not shorted to see if the amp will power up. If it does, you need to replace all in that group of parallel transistors. This is generally only viable for audio output transistors.