nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239 
|
Post by nashou on Mar 21, 2017 14:30:30 GMT -5
Ok, when you get back to it I want you to remove BD901 and set your DMM on diode scale and test it carefully. Have you ever tested a bridge rectifier before? Not really, give me a refresher  Athanasios |
|
|
|
Post by mastertech on Mar 21, 2017 15:44:46 GMT -5
You test it like it is 4 individual diodes. Set your DMM on diode scale. Put 1 probe on pin 1 and the other probe on pins 2 or 3. Each pin (2 or 3) should show flow in 1 direction but no flow in the other when the probes are reversed. Then put 1 probe on pin 4 and the other probe on pins 2 or 3. Again, flow in 1 direction but no flow in the other. Even leakage in the opposite direction is no good.
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 21, 2017 21:02:11 GMT -5
Tested fine.
|
|
|
|
Post by mastertech on Mar 22, 2017 10:13:22 GMT -5
What is the part number on it?
|
|
|
|
Post by mastertech on Mar 22, 2017 15:07:42 GMT -5
Well, I am not an engineer so I am not seeing how they are coming up with that 400vdc line. Usually there are a couple caps on the output line and all I see on this is the 1, 1.5uf/450v cap. But I do see it is a non polarized cap and I think you said you replaced this cap so I was wondering if you used a non polarized replacement.
Based on the voltage rating of the other caps on this line it does appear as though the voltage should be @ 400vdc.
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 22, 2017 15:37:05 GMT -5
9215. GBJ1508
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 22, 2017 15:40:16 GMT -5
Well, I am not an engineer so I am not seeing how they are coming up with that 400vdc line. Usually there are a couple caps on the output line and all I see on this is the 1, 1.5uf/450v cap. But I do see it is a non polarized cap and I think you said you replaced this cap so I was wondering if you used a non polarized replacement. Based on the voltage rating of the other caps on this line it does appear as though the voltage should be @ 400vdc. No I didn't replace it, But I did measure it and test its ESR and its fine. I didn't have another cap in that size or value. |
|
|
|
Post by mastertech on Mar 22, 2017 16:18:58 GMT -5
If I had to guess on that 400vdc production it would be the switching of mosfet Q902. I would go back and test every component in the red square. Your previous voltage tests on ic902 indicated it was not running so it was maybe not getting a correct input voltage or it is not working itself.  |
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 22, 2017 20:46:58 GMT -5
Well, i tested all the parts except ic902 .
I have another one. I guess I could pull it off the board and try to do some diode tests from pin to pin to see if there are any differences .
Nashou
|
|
|
|
Post by mastertech on Mar 23, 2017 14:16:42 GMT -5
What is the DC voltage on both sides of D903 using hot gnd?
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 23, 2017 15:27:47 GMT -5
167.8 and 167.7
And the diode test good with DMM and testers
|
|
|
|
Post by mastertech on Mar 23, 2017 16:37:03 GMT -5
And how about R969?
|
|
|
|
Post by mastertech on Mar 23, 2017 17:55:37 GMT -5
I think I see a problem. When you get back to this, check that voltage at R969 and a few more tests to confirm then we may try something.
|
|
nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239
|
Post by nashou on Mar 23, 2017 19:06:40 GMT -5
|
|
|
|
Post by mastertech on Mar 23, 2017 19:21:58 GMT -5
Ok, now after R970 then after R971.
Then value test R991.
|
|
