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Post by tibimakai on Apr 19, 2019 16:46:57 GMT -5
I have checked those transistors. The board boots up, just does not show anything on the display. All the big coils voltages are OK, as well. The Panasonic chip(HDMI OUT) was getting a bit too hot for my liking.
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Post by tibimakai on Apr 19, 2019 23:22:31 GMT -5
I have removed Q7018 and nothing has changed, at pin #1. Still shows 1.4 Ohm.
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Post by tjmotter on Apr 25, 2019 16:46:18 GMT -5
deleted
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Post by tibimakai on Apr 27, 2019 15:36:42 GMT -5
Ok here are the results:
Original board with Micom removed shows 49Kohm
Do you think that removed Micom, could effect the end result, or this regulator could be bad?
Ebay 800 board that has worked partially worked, shows 291Kohm
Ebay 900 board starts high, around 1.3Mohm and starts dropping fast and then it slows down to around 720Kohm.
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Post by tibimakai on Apr 29, 2019 19:57:57 GMT -5
I have removed Q7009 from the 900 board and at pin # 1 and pin #104, I measure 22Kohm, which I guess is good.
I have measured the resistance between 3.3V and 1.8V and it shows 278Kohm, which is very close to your measurement, that is good.
It is promising at this point.
In a few, I will look into checking the three HDMI ICs, to see if their power rails are shorted, or are OK.
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Post by tibimakai on Apr 29, 2019 23:02:37 GMT -5
I have measured some resistances:
TX-RZ900(removed Q7009):
Q8401
3.3VHT -Pin #204= 3.8 Kohm
3.3VHT -Pin #67= 3.8 Kohm
1.1VHT -Pin #11= 459 Ohm
Q8000
1.1VHT -Pin #7= 450 Ohm
3.3VHT -Pin #15= 3.8 Kohm
Q8302
5.0VHT -Pin #101= 3.9 Mohm
3.3VHT -Pin #112= 3.8 Kohm
1.3VHT -Pin #139= 0.97 Kohm
HDMI Out -Pin #18= 3.45 Kohm, if I reverse the leads, I get 4.4 Kohm
between 3.3VHT and 1.1VHT= 3.1 Kohm, if I reverse the leads, I get 4.3 Kohm.
On the second 800 board I'm getting very similar results. With Q7009 soldered in though.
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Post by tjmotter on Apr 30, 2019 11:50:04 GMT -5
I have two 900 boards that are bench testing similarly. Let me know if you would like me to ship them to you so that you can test them in your system. At the end of the day I need to end up with 2 DSP chips but we can figure that out later.
Todd
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Post by tibimakai on Apr 30, 2019 12:50:36 GMT -5
Do you think, that it is time to solder in, one of your Micoms? I think that I should, but you are the expert.
There are three diodes around the Micom, and they check out good as well. Two on one side, and one at the bottom corner. I'm at work right now.
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Post by tjmotter on Apr 30, 2019 14:28:00 GMT -5
Yes, I would install one of the MICOM's at this point.
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Post by tibimakai on May 3, 2019 1:17:26 GMT -5
I can't believe that I'm saying this, but I think that it's fixed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I did not have much time to "play" with it, but there is picture, I have only hooked up two speakers only and there it was sound as well.
Net is working as well.
Did a firmware upgrade too.
Tomorrow I will "play" more with it.
Initially I have left the 900 Q7001 in it, and the amp did not kick in, so there was no sound.
After swapping out the two ICs, everything seems like is working now.
Thanks a lot for now Todd.
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Post by tjmotter on May 3, 2019 16:44:46 GMT -5
Great news!! Congrats!
Just to be safe, I would change out that voltage regulator (Q7018). Perhaps just swap it with one from one of your 800 boards. As I stated earlier, this circuit seems to be capable of drawing more power than the regulator can handle so I suspect that in the 900, it either blows or causes the MICOM to blow. Putting a fresh one in is good insurance.
HTH
todd
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Post by tibimakai on May 4, 2019 0:06:21 GMT -5
OK, I have replaced it.
What I'm noticing, that the subwoofer is not getting signal.
At the moment, I only have left, center, right and subwoofer hooked up. In the configuration I have selected 3.1 channel and subwoofer on.
There is no sound, when I check the levels either, in the speaker settings. The pink noise, can be heard from the other three speakers, but nothing can be heard from the sub.
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Post by tjmotter on May 4, 2019 7:13:19 GMT -5
I have run into this before with systems that have been hit with lightning strikes. I suspect it is one (or all) of the following:
Q4697
Q4608
Q4617
Q4618
Q4121
Also check:
R4617
R4627
R4618
R4628
C4607
C4809
In your case, since the +/- 12V rails were damaged I suspect that Q4121 is blown. This is an 8 pin op-amp that could easily have been affected when these rails blew. The other transistors are the MUTE transistors for the SW channels. I recall that you worked through and replaced a lot of these but the SW ones may sit in a different section of the board so they are easy to miss.
HTH
Todd
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Post by tibimakai on May 4, 2019 14:36:19 GMT -5
Thanks Todd, I will go through them again. I thought that those transistors, will come back and bite me later on.
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Post by tibimakai on May 5, 2019 18:43:04 GMT -5
I have tested those components and some more.
I couldn't find R4617 and C4809.
They all checked out OK. I couldn't test the op amp Q4121, so I have just replaced it. At + & - to GND I was measuring some Mohm values, at that IC.
With the new one, only in the Kohm range.
What I have found bad, were the two 10 Ohm resistors R4913/R4914. They were in Mohm values. These supply the +/-12V to Q4121.
It is tempting to try it out, but I measure some weird measurements when I compare the two channels, at R4637= 19.9K/R4638=1.8K and R4607=20.1K/R4608=1.95k.
They should be measuring equally, no? Since they have the same values.
R4607/R4608, should measure 220K and they measure 19.9K and 1.95K? I understand that they are in parallel with capacitors, but they are way off, no?
R4937 seems OK, but R4638 only measures 1.8K.
These measurements are in circuit, of course.
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