From "Hack Job" to Greatness!



You have probably read by now, about Hack Shops. I just use this as a general term to group all the repair shops in that don't do the job right when repairing your amplifier. dB-r is NOT a Hack Shop. We are experienced, have been to college for Electrical Engineering Technology, well trained and experienced with a solder iron. I suppose some of the things that Hack Shops do may come from their lack of education/training. When I was in my first semester of EET, they trained us how to properly solder. It was one of the first things they taught us. I actually already knew how to do it before the training because I had been playing around inside Electronics since I was a kid. Soldering is part of the job.

For some reason, these Hack Shops cannot solder to save their lives. I see, Cold Solders (not using enough heat), Laziness, (inability to remove components from the circuit board, they cut the legs off and solder new parts to the old legs), Blobs of solder (using too much solder) etc... They just don't have the skills or they don't care. I don't know which it is, I personally don't know any of them, I just see their work when the amplifiers they repair come into my shop after failing again and again and the customer gets tired of paying them outrageous fees to do a crappy job repairing their amplifier.

So here we have, a Planet Audio TT2250D. Big class D amplifier (relatively) basically the same board as the newer model VX2200D. It uses 16 IRFZ44N on the Power Supply section (IRFZ46N if it is the newer model VX2200D), 2 large transformers, 4 Rectifiers, 2 voltage regulators, and 10 IRFB31N20D on the output section. It's a fairly powerful amp that is supposed to be 1 ohm stable, though since it lacks a cooling fan large enough to cool the entire heatsink (the little fan inside doesn't count as a "cooling fan") it will probably not last long at 1 ohm before it overheats, the Mosfets will go into thermal runaway, start drawing tremendous currents, and eventually you will get some nice stinky smoke inside your car from the mosfets on the power supply turning themselves into very expensive sparklers/smokebombs!

If you have this amp, and want to use it at 1 ohm, let it cool off between songs. Like jam it for 1 song, then kill the bass for the next song, then crank it back up after that 3-5 minute song is over and you will be okay at 1 ohm... Maybe...



Planet Audio TT2250D Hack Job repair

Click Image to Enlarge!


Lots of bad news for this beat-up old 2250D... Click image to enlarge it so you can read the text better.




**HACK JOB ALERT!**
Output FETS 10 peices of IRFB31N20D
Closeup example pic of a HACK JOB!
Click to Enlarge, then Click Again to Zoom In So you can see just how UGLY this is...
It can't be good for your FETS...




Not sure why the extra heatpad, but I think they did this because they cut the legs too
short on the new Fets or had to solder back in the old FET and the metal back of the
FET was making contact with the Heatsink You can't have that because it is a short...
If they hadn't ghetto rigged it in the first place the extra pad wouldn't be necessary!




Smoked power supply MosFets completely removed, legs and all, residue cleaned from circuit board
ready for new MosFets!




Closeup of cleaned out circuit board holes.. If I can do it, how come the hack shops just can't do it?
It's not that hard to do....




Alright! All new Power Supply and Output Mosfets installed!
I didn't get pics of the removed Outputs, but you will see the new ones installed closeup later,
keep scrolling down this page!




Closeup, all new Power Supply FET's installed.




Closeup, all new Output FET's installed.
Zoom in you can see I had to scrape away some of the coating on the board
and add some extra solder because the Hack Shop had messed up the traces




Distant shot. Ready to pre-test, put back together and final load test.
I didn't take anymore pictures after this, the customer was in a hurry to pick it up, so I finished it up and we installed the amp in his car.
It's been months now since I repaired it and it is still bangin!



The repair bill on this amp was $97.00 before tax. Was a local customer so they have to pay sales tax, internet orders from outside of Texas don't pay sales tax. It would have been only $87.00 had the output transistors not need to be replaced also. This amp, now has 16 new matching date code mosfets on the power supply, correctly soldered to the board, and 10 new matching date code output mosfets correctly soldered to the board. It will perform as good as new and be just a reliable as new if installed properly and not run at 1 ohm for extended periods of time. Considering it was ready for the trash can when it came into my shop, $97.00 for a big class D amp that is good as new is a bargain. He would have had to pay at least $200-$300 to buy a new amp of the same capabilities as this amp.

Prices vary on parts all the time, so unless I have them in stock I have to charge more/less depending on what kind of deal I get on the parts. For instance I am working on a Planet Audio VX2200D (same amp board) right now and it uses almost the same exact parts and the prices have gone up since I repaired this amp, the VX2200D will also need all new power supply and output mosfets just like this amp, but the repair bill is going to be $107.00 this time. Again, well worth the price for the power output vs. price for this amplifier.

Hope you enjoyed this little repair/semi-lesson on Hack Shops, and the work they do!