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Post by mastertech on Dec 31, 2013 17:35:54 GMT -5
Now you have to see if you have DC on any speaker outputs. I don't know about checking at the speaker terminal unless the relays are closed. Otherwise you may have to figure out where to test. Anywhere either on the out side of the final inductors or past. You may have a harness from the amp board to the relay board.You probably have DC on that FL but check the others also.
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Post by jeremy on Dec 31, 2013 17:56:27 GMT -5
I checked all the speaker terminals, the relays are all closed so they all read, the FR and FL both read positive 19 volts, so do the FL FR speaker B terminals (Both were on so I left it the way it was)
The Center SR and SL both read about 2.0mv positive so they appear to be fine.
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Post by mastertech on Dec 31, 2013 18:32:33 GMT -5
Diode test D1062, D1057, D1063 and D1058.
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Post by jeremy on Dec 31, 2013 20:21:55 GMT -5
All 4 diodes read the same forward and reverse, very high resistance one way and the opposite way reads lower
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Post by mastertech on Dec 31, 2013 21:48:58 GMT -5
This schematic is a little tough following but I got the next check. I'm not sure if this in on the same board or not cause the numbers change but it says board number AWZ8776 or AWZ8716 depending on version. Anyways your just going to have to set your DMM to diode scale and start probing legs and see if you get a short anywhere. I'll give you a list for the FL and hopefully it will go quickly. If you come across 1 that tests odd you can check it against a complimentary part in a good channel. Here's your list.
Q932,Q937,Q931,Q943,Q945,Q927,Q922,Q907,Q912,Q902,Q917
D929,D933,D931,D927,D935,D947,D957,D952,D942,D917,D922,D912
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Post by jeremy on Jan 1, 2014 10:49:03 GMT -5
MT, Didn't notice it before but R1018 on AWZ8776 (it also has the AWZ8716 number as well) is smoked, can see it clear as day, its right next to Q928
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Post by jeremy on Jan 1, 2014 10:52:07 GMT -5
R1018 reads 8k and according to the schematic its 120 ohm safety resistor, I have a non SM I can put in its place, the Q928 its tied into appears to be fine though
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Post by jeremy on Jan 1, 2014 10:56:00 GMT -5
R1017 is open as well, compared it to the surround channels which all read 120 ohm, I will replace both the FR and FL R1017 and R1018 and recheck the circuit again
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Post by mastertech on Jan 1, 2014 11:11:55 GMT -5
Yes. R1017 is FL and R1018 is FR.
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Post by mastertech on Jan 1, 2014 11:13:55 GMT -5
Before you put it back together you may want to check R1013 and R1012. These are complimentary to 1017 and 1018. Also 120 ohm.
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Post by jeremy on Jan 2, 2014 10:03:02 GMT -5
Put it all back together after checking R1013 and R1012, everything checked out fine, even the resistance that was on the FETS on the FL channel went away. Turned the receiver on and it stayed on! but about 2 seconds later something started to put a faint bit of smoke out, it was on the Pre-driver board that's connected to the amp board (the board with all the parts you gave me to check).
Pulled it all apart and checked EVERYTHING on both the amp board and pre-driver board, and I can't find anything that reads odd except the resistance that was on the FL channel that went away is now on the FR channel FETS and FL channel FETs again, its a real high resistance but the Surround and center channels do not have that resistance. and I only replaced the FETs in the FL channel.
Where do I proceed? :-\
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Post by mastertech on Jan 2, 2014 16:51:24 GMT -5
Let's concentrate on the FL for now and see where we go. Check for DC again on the FL output. If it is there then remove R1067 and R1072. Also remove R1107 so we don't get any feedback. Check for DC again. If still there then we have to work backwards. Let me know.
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Post by jeremy on Jan 2, 2014 19:50:50 GMT -5
MT, checked the FL for DC, it appears to be fine now, no voltage at all besides about -10mv. The front right channel gets about -15v dc on it as soon as the 2nd relay clicks, and shortly after I can see smoke, I think its R1018 which is smoking (my flameproof I put in place). I can check the emitters on the FR and the FETs on that as well and replace them if you want me to, since I haven't done anything to the FR besides that resistor.
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Post by mastertech on Jan 2, 2014 21:42:12 GMT -5
If the DC is on the FR then remove R1068, R1073 and R1108 and retest for DC.
Did you check all the transistors and diodes in the FR preamp section like I listed previously for the FL? If R1018 is heating up there is voltage coming in from somewhere. I can relist test parts for this channel if need be.
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Post by jeremy on Jan 3, 2014 12:13:50 GMT -5
Pulled out R1068, R1073, and R1108, only when I put it together to test for DC again the receiver wouldn't come on, it would click on and then back off immediately. I disconnected the pre-driver board that R1018 is on and the receiver came on, both power & amp relays clicked, no smoke from the pre driver board (assumed because its not being powered), and there is no DC on the FR channel anymore, it reads 6.2mv just as the FL does
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