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Post by mastertech on Mar 12, 2017 12:38:14 GMT -5
For those optocouplers, you can just bridge pins 3 and 4 with solder and they are bypassed. You do not need to jump power to the standby at the connector when these are bridged.
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nashou
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Post by nashou on Mar 12, 2017 16:35:22 GMT -5
For those optocouplers, you can just bridge pins 3 and 4 with solder and they are bypassed. You do not need to jump power to the standby at the connector when these are bridged. Should I jump them all or just the one I think is bad? 3 and 4 are the emitter and collector for that chip right? Aslo still only 169 vdc on the rectifier. Could those Octocouplers be stoping that 400 volts that shpould be there? |
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Post by mastertech on Mar 12, 2017 18:27:42 GMT -5
Only 169vdc on pins 1 and 4 of that rectifier?
What is the AC voltage on pins 2 and 3 of the rectifier?
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nashou
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Post by nashou on Mar 12, 2017 21:49:21 GMT -5
125 AC.
Nashou
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Post by mastertech on Mar 13, 2017 19:50:24 GMT -5
I am not convinced that you should have the voltage indicated in the troubleshooting section. That 169vdc looks right but lets see.
I would jump all 3 optocouplers and see what happens.
Did you change C935?
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nashou
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Post by nashou on Mar 14, 2017 11:04:15 GMT -5
If you mean C955 yes . I don't see a C935 .
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Post by mastertech on Mar 14, 2017 11:14:42 GMT -5
It is off pin 1 of the rectifier. 1.5uf/450v
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nashou
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Post by nashou on Mar 14, 2017 11:23:46 GMT -5
Just found it , it measures fine on the board , don't have
A film of that size in stock to replace it with .
I just shorted those pins and now have no voltage on the connector
At all points .
On the jumped pins for all three I have 71.1 volts .
Forgot if it's pos or neg
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Post by mastertech on Mar 14, 2017 12:21:54 GMT -5
1 of the opto couplers may be internally shorted. I would remove them all and jump the pads on the board. Just pads 3 and 4.
Also get me the voltage on both sides of R976 after you remove the opto couplers.
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nashou
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Post by nashou on Mar 15, 2017 10:53:17 GMT -5
1 of the opto couplers may be internally shorted. I would remove them all and jump the pads on the board. Just pads 3 and 4. Also get me the voltage on both sides of R976 after you remove the opto couplers. - 67.4 both sides |
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Post by mastertech on Mar 15, 2017 11:11:17 GMT -5
Are you using hot ground when testing at that resistor?
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nashou
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Post by nashou on Mar 15, 2017 11:34:20 GMT -5
Are you using hot ground when testing at that resistor? Not sure, I was using one of the grounds that the screw goes through. I assume now that it is wrong and that is a chassis ground. So I'll recheck at one of the grounds on a connector , correct? |
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Post by mastertech on Mar 15, 2017 12:42:31 GMT -5
Just look at the schematic for a location easy to access. An open triangle is hot gnd. Triangle bars is cold gnd. You must use hot gnd for these tests. Just be careful and not touch your probe end with your finger when testing. Hot gnd is not connected to protection gnd like the chassis gnd is.
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nashou
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Post by nashou on Mar 15, 2017 16:04:33 GMT -5
3.001 and 3.072
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Post by mastertech on Mar 15, 2017 16:10:10 GMT -5
That seems a little to low. What do you have on ZD913?
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