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Post by Decibel on Sept 29, 2015 14:50:09 GMT -5
Master ... if I set the meter at 20kohms scale and the value is 0.8 I assume that's 800 ohms.
If value is 1.28 I assume that's 1280 ohms.
I'm wrong?
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Post by mastertech on Sept 29, 2015 15:01:02 GMT -5
Master ... if I set the meter at 20kohms scale and the value is 0.8 I assume that's 800 ohms. If value is 1.28 I assume that's 1280 ohms. I'm wrong? Yes, but you would post "0.8k" so I know that without having to remember what you have your meter set at. You have to realize that I am not only assisting you but others here on the site also, "and" also what I have going on here "and" if assisting others in other places. So I really need you to post accurately so when I hop back to you, I don't have to try to remember everything. and post it as 1.28k Otherwise, I will think it is ohms and that would put my thinking somewhere else. Just like now. I may be leaning more to I1, based on the clarified readings. |
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Post by Decibel on Sept 29, 2015 15:16:33 GMT -5
Ok I'm sorry.
The read of R2 out of circuit is 2.4 kohms.
The read of R2 in circuit is 0.87 kohms.
The read between empty R2 pads is 1.28 kohms
The read of R62 out of circuit is 2.4 kohms
The read of R62 in circuit is 1.87 kohms.
The read between empty R62 pads is 8.08 kohms
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Post by mastertech on Sept 29, 2015 15:21:54 GMT -5
Ok, great. Here is what I want you to do. Have these 4 resistors removed: R2, R23, R62 and R83.
Then do the ohm test again on pads for R2 and R62.
Give me those 2 readings.
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Post by Decibel on Sept 29, 2015 15:55:48 GMT -5
Checked
Removed R2, R23, R62, R83
R2 pads 1.31 kohms
R62 pads 8.22 kohms
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Post by mastertech on Sept 29, 2015 16:00:36 GMT -5
Ok, it does not look like I1 is the problem. I think now would be the time to change I90. Leave those resistors removed for now. After you change I90 retest the empty pads of R2 and R62. let me know what you get.
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Post by Decibel on Sept 29, 2015 16:03:11 GMT -5
Ok I'm going to bed now. Tomorrow I'll replace I90 with one pulled from donor board.
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Post by Decibel on Sept 30, 2015 5:22:51 GMT -5
After you change I90 retest the empty pads of R2 and R62. let me know what you get. I90 replaced R2 empty pads = 7.97 kohms (was 1.31) R62 emty pads = 8.22 kohms (unaltered) |
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Post by mastertech on Sept 30, 2015 8:32:14 GMT -5
Great. Now install R23 and R83 and recheck ohms at R2 and R62.
If ohm testing is still around the same then install R2 and R62.
Leave all the jumpers in place and test board in projector and see if the blue grid now moves properly.
But only do a quick test to see if it moves. Do not try to make continuous other convergence adjustments with the channels crossed. Just see if the blue is now correct.
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Post by Decibel on Sept 30, 2015 10:26:47 GMT -5
Great. Now install R23 and R83 and recheck ohms at R2 and R62. If ohm testing is still around the same then install R2 and R62. Leave all the jumpers in place and test board in projector and see if the blue grid now moves properly. But only do a quick test to see if it moves. Do not try to make continuous other convergence adjustments with the channels crossed. Just see if the blue is now correct. Checked Now the values of R2 (mounted or empty) are the same of R62. I tried to power on the projector and the result is strange. The issue is always to blue, that's normal because I leave "crossing" circuit. So the replacing of I90 don't fix the failure. The red grid follow the green as must to do but is unstable. |
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Post by mastertech on Sept 30, 2015 11:25:14 GMT -5
Well first off I would have to assume that I90 was properly replaced and no pins are solder bridged.
Next I would ask if you tested the capacitors for short.
Then I would ask if you tested Q1 and Z2. If questionable then replace from donor board.
Last would be to replace I1 from donor board.
If still no go then I would try another I90.
Also note: that if the red grid is now unstable I would really look at pin 1 of I90 that you replaced to be sure of no solder bridging.
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Post by mastertech on Sept 30, 2015 11:37:45 GMT -5
I removed a post. Just stick to the one above for now.
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Post by Decibel on Sept 30, 2015 11:43:03 GMT -5
Master I would remove the temporary "cross"circuit. Now it generates confusion in my mind: in fact I don't understand why now the red grid appear unstable. I replaced I90 in the red circuit OK ... but with cross condition the effect of the replacing should have to show in blue.
In your opinion is helpful to other tests? I already desolder other DG445DY from donor board.
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Post by Decibel on Sept 30, 2015 11:45:38 GMT -5
You've edited the post while I was writing. What I must to do?
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Sept 30, 2015 11:52:50 GMT -5
The current limiter is common to all three colours. I think you created a new problem or the new part was broken etc. Do the tests mastertech told to do!
Pictures of what was done are also usefull.
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