Hello... I have onkyo tx-nr747 that won't turn on, protection circuit kick in, I check the unit for possible shorted components at the output of the amp, but so far none. But I can measure 22vdc at one of the channel output (SR, please see the attach circuit diagram page 40) in NH terminal 22vdc is present in both ID+ and ID- reference to ground. The rest of the channel those terminals is no voltage. any help is very much appreciated, thank you
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Re: Onkyo TX-NR747 Protect Mode
Is it +22V or - 22V?Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809 -
Re: Onkyo TX-NR747 Protect Mode
it's +22V in both NH ID+ and ID-Comment
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Re: Onkyo TX-NR747 Protect Mode
update on this problem... the +22vdc at the output of SR channel is gone, and the amplifier not power up. But I'm not satisfied with this fix, Let me share to you the history of this amplifier, the first problem of this amplifier is... it power up and stay at NG:C error code display. meaning Center Channel is no good. I reset the amp. and run the amp diagnostic again aand still NG:C is present. disconnect all the speakers and input cables and run diagnostic again still NG:C error. So I open it and check the center channel i found one resistor with little change in value but upon remving it out the board and checking the service manual and other parameter of the resistor it seems that the resistor is in acceptable value so i put it back and check every single parts in the center channel and found nothing unusual so i put it all together and test it by running diagnostic again... and the error is gone. So I return it to the owner and me myself the one put the wiring back again to make sure everything is done correctly and we test the unit and it works normally. After 4 months the owner call me again and ask my assistance again because the amp will not turn on, so i check it in his house and it's not turning on anymore. Protection circuit kick in again, but this time with no error just shutdown in few seconds. Trying to fix it via control panel, reset, re-diagnose no good because it shut off in a few second, i bring it again to my shop and check the main board for possible shorted part but none... that's the time i try to find some help in this forum. I try my luck in swapping some parts from the good channels to the faulty channel to see if the fault will transfer to the other channel . I start swapping the driver transistors of the good channel to the faulty channel. Before soldering it back i double check both transistors, and they are 100% good. I assemble it, power it up then it power on.
Last edited by benja1475; 08-12-2020, 03:46 AM.Comment
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Re: Onkyo TX-NR747 Protect Mode
Any explanation for this kind of problem... any input is very much appropriated. This is not a convincing fix.Comment
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Surprisingly enough, this receiver doesn't have the DSP chip issue. The HDMI board does not get hot, and sound over HDMI works fine.
Regardless of the input, the right channel has noise that is clearly noticeable even on average volume level. The only cases when there's no noise is when VCR input is selected (some tracks on the board are damaged, maybe that's why), or if HDMI input is selected but nothing plugged into it. In all other cases, even when no input is connected I still have the noise.
There's some logic behind it. As soon as I select an input I get only left...04-23-2025, 10:09 PM -
I am new to electronics and I'm understanding most of what I'm reading but I have a mosfet on my board that I've identified as a P-channel Trench Mosfet. I haven't a clue how to test this and what I should expect to see with the multimeter probes. I am hoping someone with years more experience than myself can help me understand how to use a multimeter to read this. Please look at the drawing I have attached to this and can you try to explain to me what I should be doing with my multimeter in diode mode and what results I should expect from a good mosfet?...
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Anyone run memory speed tests with an old X58-based triple channel 1st gen or any other >2 channel board? The one I have is a Gigabyte I think.
Anyway I had four 4GB DDR3-1333 modules in the 6 memory slots and got around 11GB/sec memory speeds assuming that it went dual channel since it didn't have enough modules for triple channel. Now I stuck in two more 4GB modules, but they are DDR3-1600. I'm still getting 11GB/sec speeds according to memtest86...
Just wondering, anyone do memory speed analysis on these triple (and higher) channel memory boards? Are there any... -
Hi,
I have this board, where I have exchanged the LGA1151 socket. During testing I discovered, that the large PCIEX16 slot won't by no force work in x16 mode, but keeps to work in x8 mode only.
I tested this with GPU-Z, also with Render Test (but tried also Furmark and Heaven Benchmark - no effect).
Tested on Core i5-9600K as well as on an Pentium G5420 and MSI NVIDIA GTX1070 and 2 other cards, including RTX3060Ti.
Board architecture definitely allows x16 mode, as all 16 PCIe lanes are present between CPU and main GPU slot (nearest to CPU).
...05-04-2025, 12:08 PM -
Hi,
i have Lenovo Thinkpad T14 gen 1 20S1 / SN: PF2M0XAG.
I moved resistor like every time and read MEC chip with SVOD4. I unlocked 3 other mainboards successfully but this one could not read. SVOD 4 Software says: "MECxxxx series in protect mode, work mass erase only". Like in screenshot.
What can i do?...
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