Problem with Monitor, Picture Is Red

aznxtc

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This Monitor came off from a Blast City Nanao MS-2930 ...When i first turn it on i had no neck glow...Checked neck board and some solder was loose so i reflowed it...turn it back on and got neck glow, but there is another problem the picture is red.

Its been sitting in my storage for 6 month..The last time i used it the picture had no issue.


cp068.jpg
 
Have you tried to turn the red down?

Figure out which drive transistor on the neckboard is for red and check it for shorts. If nothing else, pull it and see if the red goes away. If so, swap it with the Blue drive transistor. Is the picture now all blue? If so, replace that transistor...
 
How would i go about locating the red drive transistor?..Can you please show me which one is the drive transistor in the picture?..Thanks.

blastcity022.jpg
 
See those three big transistors with the heat sinks attached? Those are drive transistors - one for each color. the red pot should have a trace that goes to one. Compare all three against each other. If you find a short on any, replace it...
 
I pulled one of the drive transistor and the Red went away and is all blue now with only 2 drive transistor...I went ahead and removed one from a working neckboard and replace it in this one but the red came back...Anything else i should try?..
Also broke one of the plastic screw on the Drive transistor is that needed?...
 
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I pulled one of the drive transistor and the Red went away and is all blue now with only 2 drive transistor...I went ahead and removed one from a working neckboard and replace it in this one but the red came back...Anything else i should try?..
Also broke one of the plastic screw on the Drive transistor is that needed?...

check for cold solder joints at all 3 transistors, their corresponding resistors (the large white block ones), and all adjustment pots on the neckboard.

then for added measure, reflow the solder joints for the input signal header too.

another fun thing to try before you break out the soldering iron again is tapping the side of the cab while it's on. does the red flicker in and out at all? if so then you're definitely looking at a cold solder issue. just reflow every major component on the neckboard, really.

as for the screw, I'm going to guess that the screw is what affixes the transistor to the heatsink? also, do you have thermal paste applied to these, as well as there being a mica insulator? (it's like a sheet of plastic the same size as the transistor backing)
 
I pulled one of the drive transistor and the Red went away and is all blue now with only 2 drive transistor...I went ahead and removed one from a working neckboard and replace it in this one but the red came back...Anything else i should try?..

Well, i would go to Google and learn how to test a transistor, then see if they are actually bad or not. You may have more than one bad.

If they are okay, then look for the color processing IC and check that...
 
I tested the little transitors next to the drive transistors and five of them were bad...Would that be the cause of this?...The Part Number is A1624 on the transistors, but i can not find it anywhere online.. Is there any other Part Number Equivalent to this?...
Thanks for all the help, Much appreciated.
 
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