Audison SRX1D DIY repair

Hey everyone,

I've googled car audio stuff enough times for the diyaudio forum to pop up with some results, so it sounds like a good resource.

half of us are here because we messed something up, me too! Anyways I was running my Audison SRX1D amplifier (have been using for a couple years in the same fashion) driving two subwoofers (4ohms each / SVC) at a 2 ohm load (800watts). Recently I was listening to music and the subs / amp stopped working, wasn't too loud / and was only about 10 minutes into listening to music (so I suspect heating wasn't an issue). I looked at the amp / blown fuse / replaced and started it back up. then I got a wonderful waft of electrical burning. who knows how long that was happening, fuse wasn't blown but the red protection light was on.

so upon removal of the amp to replace it with another for the time being - I notice that one speaker wire had come loose / potentially grounded out against the outside of the amplifier housing (that's the only different variable - that's part of my equation in life with troublehsooting, either worn out / or some variable).

anyways I opened the amplifier up and took some photos. I found one transistor (I believe this is what it is) which is secured with the spiral spring design to be melted. its smoke was left on the bottom removable cover as well.

now I know this needs to be replaced, but would there often be other components which should be checked. My experience with circutry is limited - I'm very comfortable with 12 volt systems (have done car re-wires / previous job) but circuit boards...different beast. Now I may luck out, and this is all it is - and could be a relatively simple fix if the board isn't hooped and prevents me from having to learn about circuitry or buy fancy tools in an attempt to be cheap and avoid buying another $1000 amp

also included are a few other questionable things from the untrained eye, of which might just be flux or something:
-flux from capacitor (brown with clear protective tube around wire picture) appears to have stained cover plate
-thick wire coil "L10" appeared to have weeped flux / glue? the other one is clean. of course my finger is in the way but you can see some of it.
-Little resistor where it says "Q48" - flux?
-

I'll try to link some pictures from my drop box. next to it, the transistors read: 2N0605 - it appears I would need at least one need one and one spring?

[IMGHTTPSDEAD]https://dl.dropbox.com/s/39l2yolvj2ab8g6/20160409_221831.jpg?dl=0[/IMGHTTPSDEAD]
[IMGHTTPSDEAD]https://dl.dropbox.com/s/ltjtpsuzbtoqk6j/20160409_221843.jpg?dl=0[/IMGHTTPSDEAD]
[IMGHTTPSDEAD]https://dl.dropbox.com/s/8hutcszdy98undb/20160409_221849.jpg?dl=0[/IMGHTTPSDEAD]

[IMGHTTPSDEAD]https://dl.dropbox.com/s/ksae5512o9povc4/20160409_221911.jpg?dl=0[/IMGHTTPSDEAD][IMGHTTPSDEAD]https://dl.dropbox.com/s/3qkjreedvzsgfka/20160409_222121.jpg?dl=0[/IMGHTTPSDEAD]
[IMGHTTPSDEAD]https://dl.dropbox.com/s/pgywfygxpz8uvaq/20160409_222204.jpg?dl=0[/IMGHTTPSDEAD][IMGHTTPSDEAD]https://dl.dropbox.com/s/0q1im3nw4pn7iuo/20160409_221920.jpg?dl=0[/IMGHTTPSDEAD][IMGHTTPSDEAD]https://dl.dropbox.com/s/if9sa34kuaypmv7/20160409_222713.jpg?dl=0[/IMGHTTPSDEAD][IMGHTTPSDEAD]https://dl.dropbox.com/s/w9zoldfv6wbnmp5/20160409_222528.jpg?dl=0[/IMGHTTPSDEAD]
 
The burnt part appears to be a switching mosfet for a push pull power supply using a TL494 PWM chip, although I'm not familiar with this amp it is fairly common to see this is a lot of car audio amplifiers.

You will need a VOM or DVM to check all of the sm resistors marked 100. They are either 10 or 100 ohms.

You will have to replace all of the mosfets (maybe 8, hard to tell from pics) and make sure they are batch matched (same date code) order them from mouser, digi-key or another reputable parts wholesaler. E-Bay is plagued with sellers who sell counterfeit parts!!!

You will need to check the output section for shorted output devices. This can get fairly involved and will require a good DVM or VOM, soldering iron and a 20 amp or better power supply and time!! You may want to read through Perry Babins website Basic car audio electronics. before you take the plunge. It may be more economical to have the amp repaired. Check with Audison to see if they have authorized repair facilities or technical support such as parts, schematics etc. There are good reputable repair techs here in the states that can be recommended as well.

The pics you posted make it difficult to navigate your post, btw. Photobucket or some other photo server should work better.
 

Perry Babin

Member
Paid Member
2003-11-20 11:01 am
Louisiana
www.bcae1.com
PapaZBill:
If the photos are too large, reload the page after all have completely loaded and they will resize to fit the screen resolution you have.

sir ruckus:
Did you have a question about the inductor?

The liquid from the capacitor is electrolyte, not flux.

If you repair it, you will have to free the spring so that it moves freely. If the heating has caused it to lose its tempering and is now weak, you'll need to swap it for one on a component that's not as critical (doesn't produce a lot of heat).

Q48 is the component that clamps to the heatsink. The orange component is a diode.

The flux on the diode may mean that it's been replaced and whoever did it didn't clean the flux.

Before checking the gate resistors, remove the six power supply FETs.