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Post by mastertech on Jan 29, 2022 18:26:21 GMT -5
So you are saying the voltages are the same on the 2 resistors whether the posistor is in or out? I am questioning this because it does not make any sense.
Ok, so assuming your answer is yes lets proceed.
Remove R3232 and retest voltages on R3023.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 29, 2022 19:16:13 GMT -5
To be clear, I first measured the voltages with respect to the chassis mass, while the voltages across the resistors are (OFF, ON):
R3232 = 0, 0 V
R3023 = 3.4, 4.85 V
The voltage differences with posistor and without are minimal, if you want I can measure them.
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Post by mastertech on Jan 29, 2022 20:11:44 GMT -5
To be clear, I first measured the voltages with respect to the chassis mass, while the voltages across the resistors are (OFF, ON): R3232 = 0, 0 V R3023 = 3.4, 4.85 V The voltage differences with posistor and without are minimal, if you want I can measure them. Ok, here we are again. Me trying to figure out what you are posting. Maybe it is just the language translation. So R3023 is 3.4v on both sides in standby and it is 4.85v on both sides when powered on. Is that correct? And that is with the posistor removed. Correct? And on R3232 you tested 0v on both empty pads in standby and powered on? |
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micle
Junior Member
Posts: 57
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Post by micle on Jan 30, 2022 3:54:32 GMT -5
Yes correct, but the resistor R3232 (smd) I haven't removed it yet because I hoped not to since it is exactly 100 ohm, the last measurement I made with the posistor disconnected, touching a part of the resistor with the black lead and the other part of the same resistor with the red lead of the multimeter in VCD.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 30, 2022 4:26:19 GMT -5
Now pin 5 CN55 measures:
Vdc (OFF, ON)
0.003, 1.33 v (without posistor)
0.003, 1.31 v (with posistor)
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micle
Junior Member
Posts: 57
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Post by micle on Jan 30, 2022 8:44:07 GMT -5
CN55 (pin 5) POWER ON:
0.073v (first part> no signal)
3.13v (second part> middle blue led flashes)
1.31v (third party> no signal)
Following the Posistor line on the circuit you see TEMP_H> TEMP> TEMPSD5 (IC3004 pin 72)> ACWP5 / TEMPSD> TEMPERR (IC800 pin AC21), for this I am afraid that it is the broken BGA chip, but I was sure that it is he I could try to change it.
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Post by mastertech on Jan 30, 2022 10:42:24 GMT -5
Good luck. But I am done here.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 30, 2022 15:33:00 GMT -5
Sorry, the translator was wrong, I'm not at all sure it's the bga chip.
I meant that only if you tell me that the fault is with the bga chip, then I can try to change it because it is a difficult job.
For this reason, any suggestion to understand if the cause was elsewhere is still welcome, I know that in this way only you can find the fault.
However, I thank you from my heart for what you have already done.
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Post by mastertech on Jan 30, 2022 18:08:19 GMT -5
Sorry, the translator was wrong, I'm not at all sure it's the bga chip. I meant that only if you tell me that the fault is with the bga chip, then I can try to change it because it is a difficult job. For this reason, any suggestion to understand if the cause was elsewhere is still welcome, I know that in this way only you can find the fault. However, I thank you from my heart for what you have already done. Ok, no problem. Funny thing is, in the end you may be right. It could end up being ic800. But I do not like to assume the worst until my diagnosis takes me there. We may also be chasing a ghost on this temp thing. It does seem to be working because it goes into thermal protection when the posistor is disconnected and does not when it is connected. Maybe you should just reconnect the posistor and we check out some other things. What do you think? I am curious though, when you are turning the receiver on, do you just press and release the power button or do you still have to hold it for 10 seconds every time for it to turn on? |
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micle
Junior Member
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Post by micle on Jan 31, 2022 4:02:16 GMT -5
Perfect, I agree with you.
I have already done many tests with and without posistor, but the differences are minimal, however when I short-circuit the posistor I remember that the voltages were negative.
If you press the Standby button nothing happens, just holding it down for 10 sec. turns on and stays on (one click), then another 10 sec. to turn off in standby (one click). But the first 10 sec. it sends it to standby because as soon as it is powered it remains on without the wording "POWER ON" (just one click).
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Post by mastertech on Jan 31, 2022 12:49:14 GMT -5
So when you hold the power on button for 10 seconds the receiver powers up and stays on but there is nothing on the display, right?
So I still think we need to stay on ic3004 for now since it controls power up and display readout, speaker relays and such. I think you said you can test pins right on ic3004 when the unit is powered up so I will need voltages on a whole bunch of pins. I will give you a list of pins in a little while.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 31, 2022 14:47:43 GMT -5
No, only when powered up does the display not appear, then it always appears.
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Post by mastertech on Jan 31, 2022 14:51:01 GMT -5
No, only when powered up does the display not appear, then it always appears. Is that when it shows "power on" or does it display other stuff also? |
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micle
Junior Member
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Post by micle on Jan 31, 2022 15:45:14 GMT -5
It only shows "POWER ON" only and then freezes.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 31, 2022 16:01:13 GMT -5
Any key press, both when it is on and when in standby, nothing happens.
When the receiver is in standby, it can also be turned on by pressing together “TUNE ↓” and “MULTI-ZONE ON / OFF” keys for 5 seconds, "POWER ON" appears (one click) and it always freezes.
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