nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239 
|
Post by nashou on Nov 19, 2016 19:32:33 GMT -5
Yeah, that is about where we ended up before. The circuit has to be active for it to show up. How about try this. TR115 still has me bothered. Take tr116 out and put it in TR115 place. Leave tr116 empty and leave TR108 empty. Put in good transistors in tr107 and see what your B- is. ok Will do. But I was thinking about the main power in on that board from the main amp board TR343. I get about 4 volts higher there than I should be. about -53 and -54 on outer legs and -24.65 on middle leg. TR342 is inhale 49 volt range on outer legs and +26.xx inner leg. But TR343 is fine. Might be something before it? Pre amp board is connected for the readings above. www.flickr.com/photos/21885221@N04/30314168403/sizes/o/ c2.staticflickr.com/6/5582/30314168343_1e6e26a1e5_o.jpg |
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 19:40:56 GMT -5
The silk screen on the PCB show the diodes the same way. Both going to the Source's of the 2sk146's. As should be according to the Layout board and the schematic.  |
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 19:57:15 GMT -5
Just did a diode test on D329 and D328
D329 was .595 + on Band and .323 - on Band
328 is .573 + on Band and .719 - on Band.
Something is a miss here
|
|
|
|
Post by mastertech on Nov 19, 2016 20:14:02 GMT -5
The silk screen on the PCB show the diodes the same way. Both going to the Source's of the 2sk146's. As should be according to the Layout board and the schematic. Actually this picture does not show d102. |
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 20:20:05 GMT -5
oh sorry i showed D109 and D110.
'
But the Cathode side both go to the middle pins of the TR106 and 105
|
|
|
|
Post by mastertech on Nov 19, 2016 20:26:58 GMT -5
Ok, so just the schematic is wrong then.
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 20:28:50 GMT -5
Yes, I pulled D329 and am replacing it with a new NZX6V2B I didnt like the numbers there.
Nashou
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 20:40:35 GMT -5
Ok Mac. Changed D329 and now I am getting voltages that I like on TR343 !!! Under 50 and the center pin is now -25.75 .
Ir was 10 uA and the new is 1.5 uA the original spec should be 1 uA I think it was bad .
-B = -24.57
+B is now +24.96
How should I proceed ?
|
|
|
|
Post by mastertech on Nov 19, 2016 20:44:31 GMT -5
Try assembling the channel with tr107 and see what happens with the B-.
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 20:56:01 GMT -5
Try assembling the channel with tr107 and see what happens with the B-. -B voltage stayed but voltages on TR107 were bad and it blew the one half for sure not 100% sure about other half. Will pull to see. I now have 4 pieces left. But have more on order . Nashou |
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 20:58:02 GMT -5
both halves blown , so now only three good parts.
Nashou
|
|
|
|
Post by mastertech on Nov 19, 2016 21:02:12 GMT -5
Do an ohm test between tr107 each gate to B- and then to gnd.
So:
gate to B-____
gate to B-____
gate to gnd._____
gate to gnd._____
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 21:22:39 GMT -5
Do an ohm test between tr107 each gate to B- and then to gnd. So: gate to B-____TR103 side: Rose and fell then rose slowly to 3M lowest was .7M gate to B-____TR105 side: Rose from 7M slowly , stopped reading at 9M gate to gnd._____TR103 side: 47.1K gate to gnd._____TR105 Side: Jumps around shows OL then in the kOhm range then up to 40M the slowly goes down. |
|
|
|
Post by mastertech on Nov 19, 2016 21:39:26 GMT -5
That looks fine.
With tr107 and tr108 both removed what is the voltage on both sides of R139 and R140?
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Nov 19, 2016 21:47:26 GMT -5
That looks fine. With tr107 and tr108 both removed what is the voltage on both sides of R139 and R140? about 24.87 it started lower but as amp warms up it rises ever so slowly. All are about the same. Nashou |
|
