nashou
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Post by nashou on Nov 21, 2016 22:50:15 GMT -5
ok installed. Powered up it is still good. R137 out. Voltage on Drains are 3.4 but the tr105 gate side is -.557 it should be 0 . I think the gate is safe on NPN as long as it doesnt go + right? R153 has -24 each side. Nashou
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Post by mastertech on Nov 21, 2016 22:58:20 GMT -5
What are the B+ and B- rail voltages?
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nashou
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Post by nashou on Nov 21, 2016 23:06:06 GMT -5
What are the B+ and B- rail voltages? -B= -24.98 +B= +25.29 Also just rechecked the gate on TR107 and its 110mv on TR105 side TR103 side is 5mv Also Checked Gates of unpopulated TR108 the one is -2.04( TR106 side) other is mv Nashou
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Post by mastertech on Nov 21, 2016 23:10:30 GMT -5
Looks like the rails are good now. That diode was a problem. That gate would have -24v on it now if R137 was still in.
Now we have to figure out why the -24v is on the output. What are the BEC voltages on TR103 and TR105 now?
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nashou
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Post by nashou on Nov 21, 2016 23:11:17 GMT -5
I think it all looks good . -13.9 on the Sources for TR108 that be the -25 through the 9.1 zener dropping voltage to about that . not sure how the -2 gets to that gate. I like to learn how
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nashou
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Post by nashou on Nov 21, 2016 23:16:56 GMT -5
Looks like the rails are good now. That diode was a problem. That gate would have -24v on it now if R137 was still in. Now we have to figure out why the -24v is on the output. What are the BEC voltages on TR103 and TR105 now? tr103 B=3.83 C=24.92 E=3.61 tr105 B=3.89 C=24.4 E=3.63
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Post by mastertech on Nov 21, 2016 23:20:15 GMT -5
Those look great now. How about BEC for TR109
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nashou
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Post by nashou on Nov 21, 2016 23:27:44 GMT -5
Those look great now. How about BEC for TR109 B=24.69 C=11.51 E=24.91
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Post by mastertech on Nov 21, 2016 23:33:33 GMT -5
Ok, here is where the problem starts to show itself. Test for value R149 and R151, both 47 ohm, especially R149. Lift 1 leg on each to be sure.
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nashou
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Post by nashou on Nov 21, 2016 23:39:14 GMT -5
Ok, here is where the problem starts to show itself. Test for value R149 and R151, both 47 ohm, especially R149. Lift 1 leg on each to be sure. Yeah I see that the 11 is wrong. Both are good
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Post by mastertech on Nov 21, 2016 23:47:46 GMT -5
Well I think we are down to TR109,TR111,TR113,R143,R145,R147,R139. If you value test these resistors and they are ok then I guess you will have to wait until you get the replacement transistors you ordered.
Off to sleep. I'll check in tomorrow.
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nashou
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Post by nashou on Nov 22, 2016 20:48:34 GMT -5
I checked all those resistors earlier today and all measured fine.
Any other voltages you might want off the TR's
Nashou
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Post by mastertech on Nov 22, 2016 20:53:41 GMT -5
Maybe the BEC voltages of TR111 and TR113
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nashou
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Post by nashou on Nov 22, 2016 22:25:20 GMT -5
TR 111
B=22.27
C=-24.91
E=11.90
TR113
B=-24.94
C=25.39
E=-24.47
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Post by mastertech on Nov 22, 2016 22:57:39 GMT -5
Lift 1 leg of R139 and retest BEC of TR111.
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