Fosgate 1000a2 with blown output

81300sd · 26th February 2009, 01:48 PM

I am going to try to repair this. Any help is appreciated.

All of the components with red arrows are confirmed blown

Perry Babin · 26th February 2009, 02:04 PM

Do you have a variable temperature soldering iron?

Do you have a small butane torch?

Did you check for rail voltage on the blown channel when it was powered up?

In the defective channel, pull all of the 0.1 ohm source resistors and cut the output transistors free from the board. Confirm that all of the small surface mount resistors are within tolerance. The 100 ohm and 33 ohm are the most likely to have failed. There are ~20 100 ohm resistors to check.

You should replace Q321, 322, 324 and 325 even if they appear to be OK.

81300sd · 26th February 2009, 03:56 PM

My butane torch doesn't seem to be working anymore so I need to go get one.

It does have rail voltage similar to the other side.

I have cut it all free am now testing.

Perry Babin · 26th February 2009, 03:59 PM

The Radio Shack torch works well.

81300sd · 26th February 2009, 07:35 PM

Just got back with a rad shack torch and a better multimeter

R379 - 6.9k

R372 - 100.5

r378 - 4.39k

r370 - 99.6

r377 - 3.31m

r368 - 99.5

r376 - 3.39k

r366 - 99.5

r375 - 206k

r364 - 99.6

r382 - 4.55m

r383 - 24.1k

r384 - 59.1k

r385 - 35.6k

r380 - 2.14k

r381 - 489

r386 - 813

r387 - 31.5

r330 - 10.3

r332 - 22.4m

r345 - 99.5

r327 - 100.5

r329 - 470

r361 - 158k

r351 - 66.6k

r345 - dead

r359 - 101.9k

r358 - 20.02k

r357 - 56.3k

r355 - 15.3m

r356 - 817

r360 - 30.2k

r353 - 20.01

r354 - 509

r326 - 22.3

r350 - dead

r341 - 68.4

r349 - 46.6k

r330 - 101.2

r348 - dead

r337 - 99.7

81300sd · 26th February 2009, 07:35 PM

Going thru it again with the schematic. I missed some and some may be misnumbered.

Perry Babin · 26th February 2009, 07:50 PM

You don't have to post them unless you don't know how to read the value. If you post them again, post the markings also.

81300sd · 26th February 2009, 08:11 PM

Ok, so what I have found bad is

320
355
361
391
374
352
351
343
341
350
349
348
379
378
377
366
376
375
380
382
386

I do question these. Not sure what the tolerance is.
383 marked 2002. Tested 17.56k
387 marked 303. Tested 27.5k
384 marked 563. Tested 49.5k

Is there anything else I should be checking?
How many watts are these .1 ohm resistors?
Where is the best place online to get all these parts?

Perry Babin · 26th February 2009, 08:36 PM

The ones you're not sure about are probably OK. There's likely something in the circuit that's skewing the readings. Compare these to the ones in the other channel.

Mouser is probably the best place to get the parts.

Mouser part number for 0.1 ohm:
71-LVR3-0.1

The SMD resistors are in two sizes. The smaller ones are 0805. The larger ones are 1206. You'll need to order the correct ones. Order extras. They're inexpensive. On the schematic, the ones with a 'B' suffix are 0805. The ones with a 'C' suffix are 1206.

The SMD resistors that have 4 digits are 1% tolerance components and need to be replaced with 1% components. The ones with only 3 digits are 5% tolerance and can be replaced with either 1% or 5% tolerance components.

You also need to check the protection circuit transistors. They are:

Q226
Q227
Q228
Q229
Q230
Q231

81300sd · 26th February 2009, 10:16 PM

Ok some of the transistors are bad too. What am I looking for at mouser for transistors? Got everything else ready to order.

I am ordering twice the parts I need, might need them later anyway.

Edit,
Nevermind I figured it out. Just have to wait on parts. I think I will start playing with some other stuff getting my soldering mojo going

26th February 2009, 01:48 PM	#1
81300sd diyAudio Member Join Date: Feb 2009	Fosgate 1000a2 with blown output I am going to try to repair this. Any help is appreciated. All of the components with red arrows are confirmed blown

26th February 2009, 02:04 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you have a variable temperature soldering iron? Do you have a small butane torch? Did you check for rail voltage on the blown channel when it was powered up? In the defective channel, pull all of the 0.1 ohm source resistors and cut the output transistors free from the board. Confirm that all of the small surface mount resistors are within tolerance. The 100 ohm and 33 ohm are the most likely to have failed. There are ~20 100 ohm resistors to check. You should replace Q321, 322, 324 and 325 even if they appear to be OK. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

26th February 2009, 03:59 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The Radio Shack torch works well. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

26th February 2009, 07:50 PM	#7
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	You don't have to post them unless you don't know how to read the value. If you post them again, post the markings also. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

26th February 2009, 08:36 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The ones you're not sure about are probably OK. There's likely something in the circuit that's skewing the readings. Compare these to the ones in the other channel. Mouser is probably the best place to get the parts. Mouser part number for 0.1 ohm: 71-LVR3-0.1 The SMD resistors are in two sizes. The smaller ones are 0805. The larger ones are 1206. You'll need to order the correct ones. Order extras. They're inexpensive. On the schematic, the ones with a 'B' suffix are 0805. The ones with a 'C' suffix are 1206. The SMD resistors that have 4 digits are 1% tolerance components and need to be replaced with 1% components. The ones with only 3 digits are 5% tolerance and can be replaced with either 1% or 5% tolerance components. You also need to check the protection circuit transistors. They are: Q226 Q227 Q228 Q229 Q230 Q231 __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


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26th February 2009, 03:56 PM	#3
81300sd diyAudio Member Join Date: Feb 2009	My butane torch doesn't seem to be working anymore so I need to go get one. It does have rail voltage similar to the other side. I have cut it all free am now testing.

26th February 2009, 07:35 PM	#5
81300sd diyAudio Member Join Date: Feb 2009	Just got back with a rad shack torch and a better multimeter R379 - 6.9k R372 - 100.5 r378 - 4.39k r370 - 99.6 r377 - 3.31m r368 - 99.5 r376 - 3.39k r366 - 99.5 r375 - 206k r364 - 99.6 r382 - 4.55m r383 - 24.1k r384 - 59.1k r385 - 35.6k r380 - 2.14k r381 - 489 r386 - 813 r387 - 31.5 r330 - 10.3 r332 - 22.4m r345 - 99.5 r327 - 100.5 r329 - 470 r361 - 158k r351 - 66.6k r345 - dead r359 - 101.9k r358 - 20.02k r357 - 56.3k r355 - 15.3m r356 - 817 r360 - 30.2k r353 - 20.01 r354 - 509 r326 - 22.3 r350 - dead r341 - 68.4 r349 - 46.6k r330 - 101.2 r348 - dead r337 - 99.7

26th February 2009, 08:11 PM	#8
81300sd diyAudio Member Join Date: Feb 2009	Ok, so what I have found bad is 320 355 361 391 374 352 351 343 341 350 349 348 379 378 377 366 376 375 380 382 386 I do question these. Not sure what the tolerance is. 383 marked 2002. Tested 17.56k 387 marked 303. Tested 27.5k 384 marked 563. Tested 49.5k Is there anything else I should be checking? How many watts are these .1 ohm resistors? Where is the best place online to get all these parts?

26th February 2009, 10:16 PM	#10
81300sd diyAudio Member Join Date: Feb 2009	Ok some of the transistors are bad too. What am I looking for at mouser for transistors? Got everything else ready to order. I am ordering twice the parts I need, might need them later anyway. Edit, Nevermind I figured it out. Just have to wait on parts. I think I will start playing with some other stuff getting my soldering mojo going

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