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Post by mastertech on Jan 3, 2014 12:39:13 GMT -5
Ok, that doesn't make sense. Is ic903 populated?
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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 mastertech on Jan 3, 2014 13:12:09 GMT -5
On that board look for connector CN902. Should be a 5 wire harness. Test for DC on pin 4 (-15v) and pin 5 (+15v)
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Post by mastertech on Jan 3, 2014 13:13:20 GMT -5
Might as well check pin 2 also for +5v
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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 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 13:28:48 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 13:33:43 GMT -5
And R1068, and R1073 are removed as well (the emitters from the FR channel)
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Post by mastertech on Jan 3, 2014 14:05:11 GMT -5
No, all those parts, other then R1068 and R1073 are protection parts. I'm just not seeing why the no turn on condition with these 2 resistors removed but it must be something with what is causing the problem.
With the amp board disconnected so it will turn on can you test for DC at CN901 pin 11?
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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 mastertech on Jan 3, 2014 14:53:33 GMT -5
Alright, put those 2 emitter resistors back in and lets see what happens, R1068 and R1073.
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Post by mastertech on Jan 3, 2014 18:34:01 GMT -5
Did you remove D1053 previously like I had asked?
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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 20:08:39 GMT -5
I'll check D1053 out and remove it, then let you know quick
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Post by mastertech on Jan 3, 2014 20:49:19 GMT -5
You might just have a leaky fet. If you don't have spares maybe you can swap them with another channel to see.
You should be able to pull the 2 fets and it should turn on and you can then see if the DC is still there or not.
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