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Post by tibimakai on Nov 5, 2018 16:13:13 GMT -5
I'm wondering, the EEPROM shouldn't be from 838 as well?
Somewhere(I can't find it again), I have read that MICOM's software has to match (don't remember which IC it was), with the other IC's software(nand or EEPROM), to be able to "talk " to each other.
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Post by tibimakai on Nov 5, 2018 16:15:03 GMT -5
I'm also wondering, how did I have these(or some) of these voltages on, with the 717 MICOM?
Maybe a 646 software would be closer?
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Post by tibimakai on Nov 5, 2018 16:18:13 GMT -5
I'm also fighting, with the 838 that recently I have picked up. Blown center amp. Replaced everything, that was blown, but it keeps smoking the pre-amp center channel part. I can't find anything wrong there, or on the mainboard. Weird.
I also have two 646s, with HDMI in and out issues. I'm stuck. Waiting on the SII chips to arrive.
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Post by tibimakai on Nov 5, 2018 17:11:53 GMT -5
The original MICOM, that is not good anymore, can not be read by the programmer anymore?
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Post by tjmotter on Nov 6, 2018 7:59:43 GMT -5
I'm wondering, the EEPROM shouldn't be from 838 as well? Somewhere(I can't find it again), I have read that MICOM's software has to match (don't remember which IC it was), with the other IC's software(nand or EEPROM), to be able to "talk " to each other. Q7001 serves as the EEPROM for the MICOM. The issue here is that it holds the "personality" of the Receiver with things like default settings and the model of the system. If you change this out, your receiver will be an NR838 and you will not be able to turn it into an RZ800. This EEPROM is not updated by the firmware update process but the firmware update checks its value for the model number so the issue you have is that if you change this part out, the receiver won't let you load RZ800 firmware. |
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Post by tjmotter on Nov 6, 2018 8:06:38 GMT -5
I'm also wondering, how did I have these(or some) of these voltages on, with the 717 MICOM? Maybe a 646 software would be closer? Don't forget that the 717 MICOM had a blown protection circuit so it would not have gotten a signal that the main amp was blown. I suspect what you are dealing with here is that the 838 MICOM is trying to turn the system on but is finding a fault so it is shutting it down. Have you checked all of the MUTE transistors connected to directly to the MICOM? Q7000 through Q7010 and Q7021-Q7023? Note that these are listed on the schematic with a space between the last digit (so Q7000 shows as Q700 0).
I suspect you still have a blown channel on this receiver and it will always cause the MICOM to shut everything down. Have you probed the iProtect and vProtect signals to see if one of them (or both) is driving high during power on?
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Post by tjmotter on Nov 6, 2018 8:10:26 GMT -5
The original MICOM, that is not good anymore, can not be read by the programmer anymore? If the 3.3V line (pin 9 on the MICOM) is not shorted to ground (pin 11) it may be possible to read it. This is assuming that Onkyo has not set the "read protect" flag in the CPU (which they tend to do on their higher end products). |
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Post by tjmotter on Nov 6, 2018 8:21:59 GMT -5
I'm also fighting, with the 838 that recently I have picked up. Blown center amp. Replaced everything, that was blown, but it keeps smoking the pre-amp center channel part. I can't find anything wrong there, or on the mainboard. Weird. I also have two 646s, with HDMI in and out issues. I'm stuck. Waiting on the SII chips to arrive. Obviously you missed something. Did you check R5392? Your problem is likely that you missed a blown resistor higher up in the circuit. R5392 sits far enough away (physically) from the damaged areas that it is easy to miss. You really need to check every resistor on that channel and compare the values to a what you read on a good channel. In some cases you will get a reading that you think makes sense only to find that a "good" channel has a different reading. This happens because some of the resistors are installed in parallel. For example, I repaired an NR806 with a blown channel and found that they had 2x 100ohm 2 watt resistors that were (effectively) in parallel. When I checked either of them with a meter they seemed good since they would read 100ohms but when I checked the next circuit I found that they were supposed to read 50 ohms and that one of the two had blown. There was no visual evidence but when I pulled them off the board I found that one was open. Once I replaced this, the amp was perfect again. |
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Post by tjmotter on Nov 6, 2018 11:31:49 GMT -5
I'm also fighting, with the 838 that recently I have picked up. Blown center amp. Replaced everything, that was blown, but it keeps smoking the pre-amp center channel part. I can't find anything wrong there, or on the mainboard. Weird. I also have two 646s, with HDMI in and out issues. I'm stuck. Waiting on the SII chips to arrive. Also, please tell me that you are using 2SA1962/2SC5242 Power Transistors (or the new 2SC5200/2SA1943 replacements) and NOT TTA0001/TTC001 parts sourced from China. A "real" TTA0001/TTC0001 pair will cost you close to $40 with shipping. The cheap parts marketed as TTA0001/TTC0001's out of China are all fakes. I ordered a set to see if they were real and found that both transistors were actually NPN parts instead of an NPN/PNP pair. I got my money back but the vendor didn't even want them returned. If it is too cheap, they aren't real! There is one vendor in the US who sells them, B+D Enterprises. The TTA0001 will cost you $12.89 and the TTC0001 will cost you $14.86. When you tag on shipping, the total will be at least $37. |
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Post by tibimakai on Nov 6, 2018 11:35:09 GMT -5
RZ800- I will check the V and I protect levels. Good point.
These mute transistors measure a bit weird, I guess due to the internal resistor. Some of them show, like 1.2V, but some of them, 1.6V. That is normal?
I did not measure the the mute transistors next to the Micom. Did not realize, that there are more there. Course you are right, I'm looking at the schematic now.Those are different transistors, then the other ones, on the lower board, right?
I have measured the transistors in the amp section and did not find any of them shorted. Maybe I should remove the whole amp section out, while we testing the rest of the receiver?
I will check the original Micom for short. The bigger problem is, that I have used Quick Chip solder to remove it and it is full of it. Pins are bent as well. If things won't work out with this new Micom, I will give it a try and I will clean it up, and straighten the legs, as best that I can and I will measure for pin #9 for short.
NR838- I have replaced that SMD resistor, usually that and the 1037 transistor go out, I know.
I know, that I'm missing something, but I thought that I have went through measuring everything, multiple times at that channel. That is why I'm asking help, maybe I'm missing something here.
I did these amp repairs, many many times already and only once I had issues and now. 99%, I repair only amp issues, the 800 it was an impulse purchase($145 shipped with remote). I don't have knowledge, on how to repair other problems with these receivers, I'm sticking with amp repairs.
I have another 646 here, that has no HDMI output, that one has a blown channel, but it seems like it may have damaged something on the HDMI board as well. I have never had an issue like this in the past. Usually I repair the amp and the receiver will work.
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Post by tibimakai on Nov 6, 2018 11:38:14 GMT -5
I don't have at the moment, a 2x0.22 Ohm/5W resistor. I have used, two old blown ones and I have joined them, and I use them like that, it shouldn't be a problem, right?
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Post by tjmotter on Nov 6, 2018 11:49:44 GMT -5
I don't have at the moment, a 2x0.22 Ohm/5W resistor. I have used, two old blown ones and I have joined them, and I use them like that, it shouldn't be a problem, right? As long as each side connects to the middle with 0.22ohm's of resistance, it should be fine. I have seen people simply solder 2 5W resistors together and use that connection as the center pole without issues. If you can find them, I find the "Noble" brand to be the best:
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Post by tjmotter on Nov 6, 2018 12:22:00 GMT -5
I have another 646 here, that has no HDMI output, that one has a blown channel, but it seems like it may have damaged something on the HDMI board as well. I have never had an issue like this in the past. Usually I repair the amp and the receive will work. Warning: Rant in progress
I don't like the designs of the newer Onkyo Receivers. From the cheap tin heat sinks to the use of parts that are not available without a license (HDMI, DSP, MICOM ...), to components that are almost impossible to replace (take a look at the regulators they are using for Q8942, Q8952, Q8932) they simply aren't designed to be repaired. It almost seems that Onkyo (and others) have designed these to fail after 3 years so that users have to buy a new Receiver. Maybe they are following Apple's example of forcing users to buy a new phone every 3 years. In Apple's case they simply stop allowing OS updates to older iphones and wait for the application vendors to stop supporting the old OS so that the user has no choice but to upgrade. I don't like this strategy but it is less frustrating than designing a piece of hardware that is designed to fail.
I have sent many emails back and forth with TI tech support on the DSP issues. They refuse to answer any questions and refuse to make the "D" rev parts available for repairs. They claim it is a licensing issue with Dolby. Similarly, reputable vendors are not allowed to sell SiI parts due to licensing issues with HDMI and don't even ask Mouser or Digikey for a quote on a Renesas MICOM because they will come back to you in 3 weeks to explain that Renesas won't offer that part for sale.
As for the voltage regulators, take a look at one of those. On the plus side, they are available through Mouser but on the negative side, they are incredibly hard to replace. The part is about the size of the head of a pin and it has 6x 0.15mm solder-balls on the bottom (as a comparison, a DSP uses 0.60mm solder-balls). Worse, it weights only 0.000060 oz and has a reflective coating on it so if you apply heat, it is not absorbed easily by the device so the solder-balls won't bond and it is so light that any amount of air flow causes it to blow away.
Even after you do all this work, the Receiver is worth almost nothing which is why I donate all the Receivers I repair to charity. At least this way those in need can benefit.
End Rant
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Post by tibimakai on Nov 6, 2018 15:23:07 GMT -5
I'm trying to fix an Asus laptop, which has a 3.3v/5v power supply IC, It is a QFN20 package, with heatsink at the bottom. I'm having a very hard time, soldering it in properly. I never know, if it is soldered in properly or not. The kicker is, every time I remove it, somehow I manage to rip a trace as well. I have to ask a coworker, who has access to a microscope, and he solders for me a tiny wire, to make the connection. In the near future, I will get a microscope. I';m thinking of getting one from Ali, simul-focal 7x45, or 3.5x45, with a 0.5x lens and ring light. Everything is getting smaller and smaller. I don't see, why Onkyo has to go so small, with some of the components, most likely there are cheaper. What else I have noticed, that not much newer receivers show up on the bay. It's like, they have dried out. Only older generations you can find there. The newer ones, don't break anymore? I have purchased these, waiting for them to arrive: www.ebay.com/itm/Non-Inductive-5W-5W-0-22-Ohm-0-22R-Flat-Alloy-Resistor-Audio-Resistor-x5pcs/391961825009?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 |
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Post by tjmotter on Nov 6, 2018 16:41:03 GMT -5
I'm trying to fix an Asus laptop, which has a 3.3v/5v power supply IC, It is a QFN20 package, with heatsink at the bottom. I'm having a very hard time, soldering it in properly. I never know, if it is soldered in properly or not. The kicker is, every time I remove it, somehow I manage to rip a trace as well. I have to ask a coworker, who has access to a microscope, and he solders for me a tiny wire, to make the connection. In the near future, I will get a microscope. I';m thinking of getting one from Ali, simul-focal 7x45, or 3.5x45, with a 0.5x lens and ring light. Everything is getting smaller and smaller. I don't see, why Onkyo has to go so small, with some of the components, most likely there are cheaper. What else I have noticed, that not much newer receivers show up on the bay. It's like, they have dried out. Only older generations you can find there. The newer ones, don't break anymore? I have purchased these, waiting for them to arrive: www.ebay.com/itm/Non-Inductive-5W-5W-0-22-Ohm-0-22R-Flat-Alloy-Resistor-Audio-Resistor-x5pcs/391961825009?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649The newer ones are still covered by warranty and yes, I agree that the "micro" sized parts are probably cheaper because they are used in cell phones so they are manufactured in huge volume. Personally, I would pay more for something that will last more than 2 years and was repairable. Perhaps its time to walk away from Onkyo and build a home theater using Outlaw Receivers? |
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