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| Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Prima 27 inch tv.
model number Q 2770 lack of red on the screen, replaced the crt board,
with one from a working tv, but after finding r 936 open (220 ohms), picture is still lacking red, & I ca't find any resistors open, or leaky, or shorted diodes, or drive transistor. What could it be? Thanks for your time, Robin. |
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#2
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Prima 27 inch tv.
Take a 68k resistor and ground the red cathode, screen should go red with
retrace. If not you have a bad crt. Then trace the signal back from the red output devcie to the video processor is to determine if indeed you are getting red video bias and drive from that area. Good schematic and scope will assist greatly. wrote in message ps.com... model number Q 2770 lack of red on the screen, replaced the crt board, with one from a working tv, but after finding r 936 open (220 ohms), picture is still lacking red, & I ca't find any resistors open, or leaky, or shorted diodes, or drive transistor. What could it be? Thanks for your time, Robin. |
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#3
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Prima 27 inch tv.
thanks for the help but the CRT board IS bad, the unit works fine with
a test one from a working set and the pix tube is fine. I can't find what's bad on the crt board, except the 220 ohm risistor. Robin. On Sep 18, 7:55 pm, " wrote: model number Q 2770 lack of red on the screen, replaced the crt board, with one from a working tv, but after finding r 936 open (220 ohms), picture is still lacking red, & I ca't find any resistors open, or leaky, or shorted diodes, or drive transistor. What could it be? Thanks for your time, Robin. |
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#4
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Prima 27 inch tv.
If the 220 ohm resistor is bad, did you change it yet? Check the driver
transistors on the board. If it is an IC that does the drive, change that also. -- JANA _____ wrote in message ups.com... thanks for the help but the CRT board IS bad, the unit works fine with a test one from a working set and the pix tube is fine. I can't find what's bad on the crt board, except the 220 ohm risistor. Robin. On Sep 18, 7:55 pm, " wrote: model number Q 2770 lack of red on the screen, replaced the crt board, with one from a working tv, but after finding r 936 open (220 ohms), picture is still lacking red, & I ca't find any resistors open, or leaky, or shorted diodes, or drive transistor. What could it be? Thanks for your time, Robin. |
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