First of all Hello Diyaudio!! My names Bob and im really into car audio and electronics. im only 19 years old and live in detroit but am going to start college for electrical engineering this fall. I know a lot about car audio but when it comes to the actual circuit boards of an amplifier im a little lost. i just read allmost the whole bcae1 stuff on car audio and boy did it teach me a couple of things that i knew just happened but not how they happened. Anyways I bought a sundown audio SAE1200Dv1 amplifier used off of a guy on the internet. it worked fine for 3 months untill i blew my fi audio 12 inch q (Wrong factory bose kit for my Monte, dont wanna talk about it) Anyways i took the amplifier out of my car for a month while i waited on fi audio to send me a recone kit. I reconed the sub and it worked perfectly (for sure. tested it on multiple amps). Well randomly my amp decides not to give output. Iv installed over 60 systems before so i know how things work but this is a very weird issue. Sometimes ill start my car and the amplifier will play perfectly. I can drive around for half an hour with my stereo at full blast without a single issue. after i turn the car off and get back in it 5mins later it wont work at all for the whole trip. Rarely it will play and then stutter a little bit and stop working. This seems to me like a loose connection somewhere but i cant find anything. Allso the protect light never turns on and the power light is allways on when it should be. I know for sure its the amplifier because iv tested every other piece of system 3 times and even put a different amplifier in with the same conditions and it worked fine. What weirds me out on this is you would think that after playing for a while something would get hot or something and cause it to protect itself but thats not the issue. it either works 100percent perfectly or not at all randomly. The amp is still in warranty but i dont have the invoice so i cannot get it repaired by sundown. Db-r wants 90 bucks for repair which i dont mind doing but i am just so curious at this point and want to learn so bad it would kill me to let someone else repair it(i know he would do a great job). Going by what the bcae1 website says it sounds like it might be a FET issue. Prior to reading this i had no idea on what a fet was but i am decent at soldering circuit boards. I allso went through to every soldering connection that looked even the tiniest bit shakey and resolderd it. That seemed to help but now its acting just as lame as usual. I feel like everytime i get in there and start soldering it works, but after the car restarts its back to the same crap. Anyways wondering if anyone has any input or suggestions on this situation. Below i have some pics of the amp and a little vid of it randomly working and not working. Thanks in advance everyone!
Full system specs.
2004 Monte Carlo SS
230amp alt with 2 batterys
Pioneer AVH-P3200BT
Sundown Audio SAE1200D V1
Fi audio 12 inch Q in 2.5cu ft box tuned to 28hz excluding port
1/0 gauge wire ran everywhere including big 3
Everything is ran correctly for sure with gains set perfectly(about 1/4up) with no bass boost.
Full system specs.
2004 Monte Carlo SS
230amp alt with 2 batterys
Pioneer AVH-P3200BT
Sundown Audio SAE1200D V1
Fi audio 12 inch Q in 2.5cu ft box tuned to 28hz excluding port
1/0 gauge wire ran everywhere including big 3
Everything is ran correctly for sure with gains set perfectly(about 1/4up) with no bass boost.
Chris at dB-r would be the best source of information but we can try to troubleshoot it. The first thing I'd suggest that you do is to measure the DC voltage on the TL494 driver IC in the power supply.
Do this while it's working properly and when it's malfunctioning. Post the voltage for both conditions. Copy and paste the following into your reply. Don't allow the probes to slip. Insert a 15 amp fuse in the B+ line while testing for additional protection in case you make a mistake (probe slip, etc.).
IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
Do this while it's working properly and when it's malfunctioning. Post the voltage for both conditions. Copy and paste the following into your reply. Don't allow the probes to slip. Insert a 15 amp fuse in the B+ line while testing for additional protection in case you make a mistake (probe slip, etc.).
IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
These amps are known for vibration related failures. Sounds like you possibly have some kind of intermittent connection inside the amp. I just got this exact same amp back from chris at db-r. I've repaired quite a few amps but I could not find the issue with this one although mine was just stuck in protect so it was a different problem. Chris did a great job with the amp. You can't tell what he worked on and he even added supports for the board to help cut down on the vibration issues this amp is known for.He made it more reliable than it was before I sent it to him. I feel it was well worth the money spent to bring it back to life even though I usually make my own repairs. Welcome to the board. I live in Charlotte,Michigan which is just outside of Lansing. I have an Fi Q too, 15 incher though. Nice subs.
I should add that while trying to trouble shoot my amp I noticed that about half of the power supply fets had faulty solder connections on their leads. The only thing holding them in the amp were the transistor clamp downs as when I removed them I could pull the fets out with nothing but my fingers. Before you send it off you may just want to actually pull the board and inspect the solder connections on the underside of the board. Be careful if you have to remove or resolder any of the smaller solder connections/through holes. They are very easily damaged even with moderate heat. It doesn't take much for them to lift right off of the board.
Thanks everyone good advice. I just checked all the fets with a dmm and there all giving the same readings, I assume that means they are all fine. And ill be honest i dont even know where the power supply is. In the first picture up there you can see this black box looking thing. It appears to be glued over something that they didnt want you to mess with because i cant get it off with gentle pressure and there are no screws or anything. Is the power supply under there? and going by how the amp acts up im more inclined to think the power supply is fine but somewhere along the line it loses the rca signal. At least thats my unexperienced guess.
The driver board is encased in that black box. Don't even bother messing with it. All the components are encased into a very hard black epoxy.I don't think it is really serviceable. The driver board itself is soldered onto the main board by 10 to 20 pins. It does not simply pull off. The power supply fets are the 6 fets on either side of the board(12 parts total) that are closest to the power and speaker terminal end of the amp. If you take off the transistor clamps I believe they are IRF3205. For the most part the components on this end of the amp make up the power supply.I would still check the solder contacts on the bottom of the board. Mine all measured ok too but they clearly were loose when the solder points were inspected. I'm not saying this is your issue but it is worth a look. Definitely read Perry's basic car amp repair tutorial.
I allready tried the checking out the board and there were alot of solder spots that looked shakey. i resoldered everything that looks remotely shakey and am still having the same issue. It did seem that it worked "better" after i resoldered the connections but its still only works 30percent of the time
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