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Post by jhinzuo on Aug 31, 2022 10:35:22 GMT -5
Hey guys my dad brought me over this amp because it stopped working out of nowhere.
The relais clicks on and after a few seconds locks up and the HDMI Led starts flashing red. This is Indicating that the DC Protection kicked in. I tried resetting it but will comeback after a few seconds. I Found a manual online and starting looking for the voltages from the protection but they are both on 3.3V Temp + DC protection.
Another weird thing the Display doenst work anymore. It should display something for a few seconds before the protection trips again right ? Found that the Transformer should have 2.27 Vac to 2.28 Vac on the Orange line but its like .1 going to like .8 or so when powering on.
Does anybody have a clue where I can start the troubleshooting ?
Also took everything apart cleaned it and put it back together, there is no signs off damage on the board
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Post by tibimakai on Sept 2, 2022 10:13:51 GMT -5
DC protection, it means that you have shorted(high current) final transistors(most likely, other components are affected as well). If you keep resetting, sometimes things blow up.
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Post by jhinzuo on Sept 2, 2022 14:25:39 GMT -5
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Post by tibimakai on Sept 2, 2022 16:10:24 GMT -5
I would start with the final transistors on the heatsink. When you find shorted transistors(usually a pair of them), I would check all the parts at the channel, to find everything that is blown. Than replace all the blown parts and measure them again, to be sure that you did not miss something. It is a good idea, to parallel check with another channel, that has the same configuration(left channel has issues, then compare it with the right channel).
Usually I work only on Onkyo receivers, so I'm not familiar with Pioneers. On some Onkyos, there is an idle current adjustment as well, that should be done(if there is a small pot at each channel, than that has to done as well).
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Post by jhinzuo on Sept 2, 2022 17:19:48 GMT -5
i have just checked all the outputs transistors and none of them are shorted. I have checked the amp6 circurt transistors aswell as them on the main assembly. Im still searching for a blown part the most i can find was a little bit off dust covering the mosfets.
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Post by mastertech on Sept 2, 2022 19:29:56 GMT -5
starting looking for the voltages from the protection but they are both on 3.3V Temp + DC protection. Where are you testing for the 3.3v protection? |
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Post by jhinzuo on Sept 3, 2022 4:13:22 GMT -5
I've tested the pin85 and the pin70 on the ic2023. Since thats that the manual refers to.
I found on the Main Assy that R588 R589 got hot since on the underside its a little brownish. they both read 104ohms. the manual says those are for the swchannel of the amp circuirt. looking closer with the camera the area does look very slighty burnt /black.
my next clue would the sw channel on the amp6 board but i just found in the manual that the pin 85&70 are both just for the AMP6 Protection. So it might not even be on the AMP Assy. ( manual says : Pin85 AMP6 Assy protection detection signal input pin (ASO = 0.82 V, DC = 1.39 V)
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Post by mastertech on Sept 6, 2022 13:20:26 GMT -5
Where in the manual does it state that R588 and R589 are for the SW channel?
What do you think the manual means when it refers to "AMP6"?
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Post by jhinzuo on Sept 8, 2022 12:30:32 GMT -5
AMP6 is the name of the Amplifiing motherboard.
The manual shows a path going from SW to that. Its not written there just drawn like a path but i might missinterpreted that. I can screenshot the part i mean.
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Post by mastertech on Sept 8, 2022 18:13:33 GMT -5
From what I see in the manual, R588 and R589 are for power to ic400, +/- 6.8v. From what you have stated and looking at the manual I have not seen anything that would direct a problem to the SW channel. I would suggest you test dc voltage at R588 and R589 to see if you have the correct voltages. It would not be the first time we have seen a volume/switcher ic cause a protection error. It is odd though that you are testing the correct 3.3v at pins 70 and 85 and have a flashing HDMI led.  |
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Post by jhinzuo on Sept 8, 2022 20:11:49 GMT -5
Thats what i was thinking. But the manual explicitly says its only the AMP6 Circuit protection so that pin might not catch problems from the main assembly. How much Voltage should those 2 resitors have they both read about 0 maybe 0.01-0.02. ( its correct to test on the 2 pins of the resitor right just double checking )
I found out if i unplug the cn203 (dcprotection is written next to it) the protection wont happen. whats the next step checking where that voltage comes from right and see if the origin of it works right ?
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Post by jhinzuo on Sept 11, 2022 8:25:15 GMT -5
update:
The Amplifier wont go into protection when the whole AMP6 Assy is disconnected. So im investigating this more now.
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