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Post by jeremy on Jan 3, 2014 20:08:39 GMT -5
I'll check D1053 out and remove it, then let you know quick
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Post by jeremy on Jan 3, 2014 19:33:39 GMT -5
Okay, well now I know what's causing it to not turn on. I put those back in and it powers on, but now that smoking issue is back on the pre-driver board The DC on the FR stabilized at +20.52v DC, the FL had a bit higher negative voltage for millivolts this time, around -30mv DC still pretty much nothing compared to the FR.
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Post by jeremy on Jan 3, 2014 14:33:14 GMT -5
On CN901 Pin 11 there is no DC voltage (well 1mv if that counts)
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Post by jeremy on Jan 3, 2014 13:33:43 GMT -5
And R1068, and R1073 are removed as well (the emitters from the FR channel)
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Post by jeremy on Jan 3, 2014 13:28:48 GMT -5
I don't suppose my issue could have anything to do with the amount of parts removed from the amp board would it? I still have D1052, D1055, R1108, R1107 removed from the amp board, as well as Q1056 and Q1057. Should any of this be put back in?
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Post by jeremy on Jan 3, 2014 13:26:13 GMT -5
+5v is there in standby and powered up on pin 2
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Post by jeremy on Jan 3, 2014 13:23:33 GMT -5
If by CN902 you are referring to CN1651 in the schematic which has a 902 next to the 5 pins (and also the +15 and -15v dc) then yes I checked those pins and both have -14.7v and +14.8v dc (with CN155 unplugged) if I plug CN155 back in, then the receiver will not come on, and it doesn't stay on long enough to do a voltage check.
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Post by jeremy on Jan 3, 2014 12:48:17 GMT -5
Yes there is an 8 pin through hole chip with number 4558DX in that spot
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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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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 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 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 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 10:49:03 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 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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