dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15 
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Post by dsmcasey on Jan 22, 2016 16:16:26 GMT -5
Hello, I purchased two store returns for next to nothing and have taken them home and began looking into them. Both have the same error message and here are the details on each. I also have pictures. I'm just not sure where to go from here. I have the service manual but this is my first time working on AVRs (I build computers). I tried clearing the codes but they come right back up, so there is definitely an issue somewhere. The same code shows on both of the units NG: LCRSLSRBLBR TX-NR646 I have it all apart. I cannot see anything physically wrong with it. All the fuses check out, connectors are good. I took out most of the boards and looked at all the circuits. The caps look great, I don't see any issues. I checked all the transistors and they seem fine to me.      TX-NR545 This unit has been dropped. The case has a bend on the top and it had a rattle. I opened it up and found a small black piece of plastic from the chasis inside that was rattling around. Checked all the fuses on this unit but have not dug terribly deep in it. The bend in the chasis is on the top but I cannot see where the plastic piece came from. Must be somewhere behind the front panel perhaps.   |
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Post by mastertech on Jan 22, 2016 16:52:29 GMT -5
So I am guessing that you plug it in, push the power button, you hear the main relay click, the code is displayed and then it shuts back down. Is this correct?
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 22, 2016 16:56:32 GMT -5
I hear relay clicks and the code shows. If I reset the code it shows the volume level for a second or two then shows the code. It doesn't power down till I power it down.
I am holding Standby and Enter to clear the codes as it suggests in the service manual.
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Post by mastertech on Jan 22, 2016 17:16:43 GMT -5
On the 646, go to the amp board and check fuses F6401, F6402, F6403 and F6404.
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 22, 2016 17:46:06 GMT -5
Just double checked, those are good.
for the record the 646 is my main goal here. I want to use it!
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Post by mastertech on Jan 22, 2016 21:45:38 GMT -5
When you say you checked all the transistors, do you mean the output transistors on the heat sink? They all tested good?
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 22, 2016 22:01:39 GMT -5
yes the transistors on the heatsink. Maybe I mistested though I just tested for resistance and they were all the same resistance. But they may not get stuck open- since they are transistors after all, so maybe I was incorrect.
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Post by mastertech on Jan 22, 2016 22:32:54 GMT -5
Test them in diode test mode. They are in pairs per channel. So you can compare the readings between pairs and see if there is a difference.
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 23, 2016 0:24:37 GMT -5
My multimeter doesn't have a diode test mode  I will pick up one that does tomorrow. I am assuming diode test mode is testing the voltage through the transistors, if that is the case, I should have it plugged in and "on" (as much as it can be). Correct? |
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Post by mastertech on Jan 23, 2016 9:59:07 GMT -5
No, unplugged. Meter supplies what it needs.
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 23, 2016 12:24:52 GMT -5
I picked up a craftsman multi and checked them all I got 605 - 1700 testing from center pin to each edge pin on all transistors. I checked the 545 as well and got the same. I didn't get any "beeps". Power off, as you said.
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Post by mastertech on Jan 23, 2016 16:04:17 GMT -5
Well you are going to have to start checking voltages. You will probably have to solder a jumper wire across the power relay so the main transformer is powered all the time. Otherwise you may not get accurate reading. If you do not know how to do this, ask.
Then I would start testing with you DMM on DC voltage and first check the + and - 15v regulators, Q4170 and Q4171 on the ASP board (BAAF-1720). Test for correct voltage on the outputs of each. Post your findings.
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 23, 2016 16:08:54 GMT -5
Master,
I do not know how to keep this main power transformer on all the time, can you elaborate? Thank you so much for all your help so far. I greatly appreciate it.
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Post by mastertech on Jan 23, 2016 16:47:27 GMT -5
On the power supply board, locate relay RL9001(see green circle in pic) and solder a jumper wire across the 2 legs with the red line going to them. Just remember that as soon as you plug it in now the whole unit is powered. So watch where you put your fingers and test probes.  |
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dsmcasey
New Member
Workin' on a pair of Onkyos!
Posts: 15
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Post by dsmcasey on Jan 23, 2016 18:27:11 GMT -5
   Master, Apparently I was doing the reset code sequence incorrect. I thought you had to hit enter and standby/on at same time or even hit ON first, apparently you have to hit enter THEN standby/on. Now, both units are going through AMP testing after reset. I tested both areas you suggested on the NR646 and did not have to wire the power supply to stay on. One of the spots showed 25.1 and the other spot showed -25.8 on my multimeter and were very stable, changing dramatically with power off (of course). I assume this points to a resistor or something not working as it is printed on the board right there 15v. Note: This was a bit of a bear to test. I had to take it apart, and run some lead wires to both of those areas then reassemble with the leads attached to my multimeter. TX-NR646 Amazingly, it WORKS sometimes!? After a clear it won't work, but if I unplug it after a clear and plug it back in it seems to work until I power it off and power it back on. I can't get it to consistently do it and I have NO IDEA why its working. I made it work twice, but I couldn't replicate it I'm not sure how I was getting it to work exactly.. But it is working for a few mins at least. I didn't have speakers hooked up either time I got it to work but I was able to change inputs and adjust volume and everything seemed to be working fine. The code on the display is now: NG C SLSRBLBR . When I hit enter it says: DET. PROTECT I TX-NR545 Multiple resets and it still will not come to life for me. However, the code has changed as well with my resets. After amp diagnostic runs, it shows: NG L R. When I hit enter it says: DET. PROTECT I |
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I will pick up one that does tomorrow. I am assuming diode test mode is testing the voltage through the transistors, if that is the case, I should have it plugged in and "on" (as much as it can be). Correct?
