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Post by mastertech on Aug 18, 2015 17:42:47 GMT -5
Ok. Well we have some options. We can continue hunting around and try to narrow it down more or we can take a quick shot in the dark and change the crystal. I have had the same exact problem before on a different piece of equipment and it was the crystal causing it. It would be nice if you had one on an old parts board. It is location X7001 and looks like a 3 leg, 5mhz crystal. I cannot tell if it is SM or through hole.
Now if you change that and it still pulses then we can continue to try to narrow it down but I think just trying this first could save a lot of time. Many micro processor use a crystal in order to function.
You can try removing it and see if the pulsing goes away but I suspect it will. But the chip is just dead then anyways so it would not be a conclusive finding. Only changing it with a known good one will tell you if that was the problem or not.
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Post by dolivas27 on Aug 18, 2015 17:49:46 GMT -5
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Post by dolivas27 on Aug 18, 2015 17:54:53 GMT -5
Ok I found one on an Onkyo TX-NR626 HDMI board I have here going to remove it right now.
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Post by mastertech on Aug 18, 2015 17:57:04 GMT -5
ok
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Post by dolivas27 on Aug 18, 2015 18:36:49 GMT -5
Ok new crystal is in and it's still pulsing?
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Post by mastertech on Aug 18, 2015 18:48:03 GMT -5
Ok, testing will be the same, board out and only P/S harness. Lets check Q7013. DC voltage, secure you neg probe on a common ground and just leave it there. Give me the voltages on pins 1,2,3,7 and 8 of Q7013
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Post by dolivas27 on Aug 18, 2015 18:57:43 GMT -5
Ok here you go.
Pin 1 = 3.3v
Pin 2 = 3.28v
Pin 3 = 3.27v
Pin 7 = 0v
Pin 8 = 3.3v
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Post by mastertech on Aug 18, 2015 19:05:22 GMT -5
No pulsing?
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Post by mastertech on Aug 18, 2015 19:08:01 GMT -5
If answer is no then check at R7073 off of pin 14 of Q7009
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Post by dolivas27 on Aug 18, 2015 19:29:14 GMT -5
No it's not pulsing and the voltage on pin 14 is 3.3v
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Post by mastertech on Aug 18, 2015 19:51:54 GMT -5
Ok, I guess we need to speed this up. You are probably not going to like this next one but it is not as bad as it sounds, lol. Same testing process but I need you to test on every pin on Q7009. But all you are looking for are any pulsing lines. But don't just look at 3.3v lines. You may find one or more that are only tenths of a volt but pulsing. I need to know these pins also. So I need you to check all 144 pins but only write down any pins you find a pulsing voltage on.  |
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Post by dolivas27 on Aug 18, 2015 21:00:46 GMT -5
Ok here's the pins I found pulsing on Q7009
Pin 3 = 0 - 2.4v
Pin 58 = 0 - 3.3v
Pin 59 = 0 - 3.3v
Pin 71 = 0 - 3.3v
Pin 72 = 0 - 3.3v
Pin 109 = 0 - 3.3v
Ok for kicks I decided to test the voltage on Q7001 EEPROM seeing how the Pin 109 was pulsing on Q7009
Pin 1 = 0 - 3.3v
Pin 2 = 0v
Pin 3 = 3.3v
Pin 4 = 0v
Pin 5 = 0.00 - 0.17v
Pin 6 = 0.07 - 1.4v
Pin 7 = 3.3v
Pin 8 = 3.3v
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Post by mastertech on Aug 18, 2015 21:20:35 GMT -5
Ok, remove R7077 and R7080. Should be near Q7010. Retest for pulsing at R7030. If still pulsing, remove R7035, should be off pin 109 of Q7009. Recheck for pulsing at R7030. Let me know what you find.
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Post by mastertech on Aug 18, 2015 21:26:14 GMT -5
Ok for kicks I decided to test the voltage on Q7001 EEPROM seeing how the Pin 109 was pulsing on Q7009 Pin 1 = 0 - 3.3v Pin 2 = 0v Pin 3 = 3.3v Pin 4 = 0v Pin 5 = 0.00 - 0.17v Pin 6 = 0.07 - 1.4v Pin 7 = 3.3v Pin 8 = 3.3v Ah, I see we have a small pulse here. Could be a bad Eeprom. But it is not shorted out. Removing R7035 may stop the pulse but if still pulsing with suggested resistors removed you may have to remove the Eeprom and test for pulse at R7030. |
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Post by mastertech on Aug 18, 2015 21:31:17 GMT -5
Oh, I forgot. If after all this it is still pulsing then remove R7048, off pin 3 of Q7009 and retest for pulsing.
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