I am working on a PDX1.1000 that currently Powers up but has no audio, or gate drive at the outputs. All outputs were replaced (IRFB4227), all 6.8 ohm resistors were replaced, both IR2010s ICs were replaced. Currently the amp powers on and idles without going into protection. The rail voltage is uneven however, +59v and -56v. I purchased a PDX1.600 to compare operation using a working similar amp. Comparing the IR2010s voltages, I can see that voltage is missing from Pin7. Also, pin11 and pin12 should be more different compared to each other.
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IR2010s voltages:
1) -56.48
2) -56.48
3) -44.92
4) -0.16
5) -0.16
6) 0.01
7) -0.01
8) -0.09
9) -0.14
10) -0.13
11) -44.92
12) -44.92
13) -46.45
14) -44.92
15) -56.52
16) -0.16
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IR2010s voltages:
1) -56.48
2) -56.48
3) -44.92
4) -0.16
5) -0.16
6) 0.01
7) -0.01
8) -0.09
9) -0.14
10) -0.13
11) -44.92
12) -44.92
13) -46.45
14) -44.92
15) -56.52
16) -0.16
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Unfortunately I am unable to get any kind of audio signal or square waves while probing this amp with the scope. All I get is the wave pictured below. This is the same wave I get on the RCA input terminal, the output legs, the ground terminal, everywhere. It's as if the amp is producing rail voltage but is asleep...
The other thing that the amp is doing is most times, when powering up, the lights come on and there is a pulse of current draw and then it shuts down and attempts to turn on again. To get it to stay turned on, I have to probe some of the IR2010s pins with the voltmeter. The black probe is on the ground terminal, and it is either pin 14 or 15 that the red probe touches and the pulsing stops.
I probed the PDX1.600 and can see all of the various waveforms that I should be seeing in the 1000.
The other thing that the amp is doing is most times, when powering up, the lights come on and there is a pulse of current draw and then it shuts down and attempts to turn on again. To get it to stay turned on, I have to probe some of the IR2010s pins with the voltmeter. The black probe is on the ground terminal, and it is either pin 14 or 15 that the red probe touches and the pulsing stops.
I probed the PDX1.600 and can see all of the various waveforms that I should be seeing in the 1000.
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Amp currently refuses to turn on again. Right now, probing the IR2010s legs no longer allows it to power up. The power light comes on when remote is applied, but quickly turns off and comes back on again, repeatedly. This time however, there is no current draw indicated by the mains testing bulbs I have installed. I will try changing the ICs again, unless there is something else to try, or change that may allow it to power up.
Lifted pin 13 on both IR2010s and connected them to pin3. Amp turns on with rail voltage every time now.
Tested for audio on R340 and R341 with voltmeter set to AC voltage since I don't get anything with the USB scope, anywhere in the amp. I have the AC voltage fluctuations on R340 and R341. Could not get to the terminals of E301 and E302 since the amp is in the case with FETs clamped down, for safety.
IR2010s: IC307 / IC308 black probe on - rail
Pin 1: 0.0 (-0.08 reduces to 0.0 as probe touches)
Pin 2: 0.0
Pin 3: 11.57
Pin 4: 0.0
Pin 5: 0.0
Pin 6: 56.03 / 55.32
Pin 7: 55.32 / 53.52
Pin 8: 55.74 / 55.10
Pin 9: 0.16
Pin 10: 0.16
Pin 11: 11.59
Pin 12: 11.58
Pin 13: 11.59
Pin 14: 11.58
Pin 15: 0.0
Pin 16: 0.16
Tested for audio on R340 and R341 with voltmeter set to AC voltage since I don't get anything with the USB scope, anywhere in the amp. I have the AC voltage fluctuations on R340 and R341. Could not get to the terminals of E301 and E302 since the amp is in the case with FETs clamped down, for safety.
IR2010s: IC307 / IC308 black probe on - rail
Pin 1: 0.0 (-0.08 reduces to 0.0 as probe touches)
Pin 2: 0.0
Pin 3: 11.57
Pin 4: 0.0
Pin 5: 0.0
Pin 6: 56.03 / 55.32
Pin 7: 55.32 / 53.52
Pin 8: 55.74 / 55.10
Pin 9: 0.16
Pin 10: 0.16
Pin 11: 11.59
Pin 12: 11.58
Pin 13: 11.59
Pin 14: 11.58
Pin 15: 0.0
Pin 16: 0.16
For future refrence:
If the caps are electrolytics with an exposed metal can on top, touch to that.
Try disconnecting the SD pin of one IC at a time to see if it's one of the ICs that are causing the amp to shut down (possibly due to a bad IC or bad input to the IC).
Are you going to be able to get the scope working again. It's going to be difficult to troubleshoot without it.
If the caps are electrolytics with an exposed metal can on top, touch to that.
Try disconnecting the SD pin of one IC at a time to see if it's one of the ICs that are causing the amp to shut down (possibly due to a bad IC or bad input to the IC).
Are you going to be able to get the scope working again. It's going to be difficult to troubleshoot without it.
The scope works fine on the PDX1.600 as I am able to see all sorts of square waves and such when probing the IR2010s in that amp. It just does not show me anything except that one waveform in this amp, no matter where I probe.
Disconnecting either pin3 to pin13 jumper returns the startup hiccups but the current draw pulse is once again visible on the mains testing bulbs. I did not reconnect either pin13 to the pad though.
I have audio on the center leg of Q303 and Q304.
Disconnecting either pin3 to pin13 jumper returns the startup hiccups but the current draw pulse is once again visible on the mains testing bulbs. I did not reconnect either pin13 to the pad though.
I have audio on the center leg of Q303 and Q304.
What do you want me to probe with the scope? I can try the various points you stipulate and we can see if we get results. The first pic below is both probes on opposite legs of the negative rectifier, so I am able to see something other than that one waveform. The second and third are of audio scoped from the top of E301 and E302.
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I get different audio waveforms depending on the ground location. The rectifier outer legs look the same whether i use the ground terminal or the RCA ground. The audio scoped most accurately when using the RCA shield ground. The pics are of different configurations with each ground.
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