Test class d dwm drive board separately

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The first picture is tl072 pin 1,thw second picture is the lm... With resistors.. I think it is OK.
The last picture is pin 1 of irs. Common ground.
 

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I think you are doing a bit of a mess. Repairing these boards is pretty simple, intuitive and logical. The structure is formed by a modulator that generates a modulated signal based on its analog input, after being sent to a pair of transistors in "emitter follower" configuration (MMBT3904 & MMBT3906), it is then sent to a transistor that splits everything on reference of the negative rail (MMBTA92), then to the respective pin 1 of all the IRS21844, for this reason we simply proceed in step. Just know that the various tests have different reference points, for example, as long as you check the modulator (before the MMBTA92 transistor) the reference is GND, as soon as you pass the modulator (after MMBTA92) the reference is the negative rail. Among all these components there are some key interconnection components that can be damaged, for example, near the MMBTA92 there are resistors (typically 820ohm and 2.4 / 2.7k) which often break after a catastrophic failure, also on pin 1 of all IRS have 10k resistors that can take damage so they need to be checked. The modulator rarely suffers damage, because it is electrically isolated enough from the very high voltage part. Keep in mind, however, that when you test the card out of the amplifier, you should expect signals a little different from those you would have if you try the card on the amplifier, because on board the amplifier there are some components that you do not have outside, such as example 2.2k 5w resistors going to GND. To realize what I'm saying you should look at the schematic of any Korean board (which uses this driver card) and you will understand.
 
Hello, yes i think i done a mess.. It seems, that i have the audio signal on the ground +-5V line.
Maybe i should build my power supply the same like yours... Maybe that will help. I repaired allready a lot of these cards, but sometimes there are failures, which are shown only when the amp is fully build back. For that, i want to test the card outside. I think its more easy to check the deadtime and amplitudes more easy..
 
As I told you in a few posts ago, I agree, testing these boards outside the amplifier helps a lot, but don't think that's all. Testing these boards separately helps you understand if the circuit is working logically, but the actual test is another. When you test the card externally, you will be able to see if the modulator is working, you will be able to see if the low side outputs of your IRS21844S are present and through that trick I showed you in post # 31, you should be able to see too the outputs of the high sides (if all the components around the IRS and the IRS themselves are ok). Keep in mind that in my previous post, I told you about a 2.2k 5w resistor that is on the amplifier, during the tests with the card outside the amplifier, it would be good to use that resistor (even 1/4 watt) and you should place 4 (1 for each IRS) that goes from VS to GND to simulate its presence (just like when the board is mounted on the amplifier) ​​only in this way, you will get the signals identical to how you would have obtained them on the amplifier (without mosfet). As in reality there are 1000 other things that can create problems (feedback, switching times, dead times determined by the 10 / 15k resistors on pin 4 of each IRS21844, worn or shorted output capacitors, damaged or shorted output inductors ) the only real test you can do after repairing the board is to remove the power diodes and inject on the rail capacitors, a significantly lower dual voltage to avoid doing damage in case of trouble, such as + / -20v. If everything is ok, the amplifier will work (at very low power) and you can check if something is heating abnormally without breaking anything. If there is any problem, you will notice it but the low voltage will not be sufficient to create immediate damage. I want to clarify that this proof was kindly illustrated in Perry's guide, which I warmly thank.
 
So, I tried today on a 10k amp. It was impossible to get the wire trough the windings in the board, so I took my supply with +30 0 - 30v. Mounted some headlamps between the supply lines. I had to repair all vias on the drive board, because the previous owner damaged them all. Both banks on the left side are working. On the right side one bank is floating, one is dead.. But now I can work more safe. Later on, I will make the supply more clean for further works.
 

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Just think, I just finished repairing 8 pieces like yours for a guy crazy for his crazy car like him. Usually, when I have problems with broken or damaged tracks, I intercept the track where it is still visible and I reach the lead of the driver card with a cable of suitable section and twist it on the lead, then soldered with tin (strictly with pb). It takes patience and precision.
 
Between SD and Vss could be the muting transistor. Are they using a JFET or a bipolar transistor in this amp?

Resistor legs work well but I'd advise laying down enough length so that you can work with the terminal end without it desoldering itself.

Ribbon cable also works well for low-current traces. Use desoldering braid (filled with solder) for higher current traces.

Look at the Repairing Physically Damaged Traces page of the tutorial, section 5. I don't think it's possible on this amp because it appears to be more than 2 layers but it may be helpful with other amps.
 
If i remember, VSS in irs21844s is negative rail, so if you have low resistance from vss to SD, you have a damaged IC, because, from pin 2 there is only a 1nf cap go to -rail (hard to damage) that determines the delay time at power on and an inductor that connect pin 2 to the onboard (driver board side) protection system provided from LM293, in addition pin 2 of the IC go to the "external" (amp side) protection system, provided by PS driver board.
 
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