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    CPD1604S Vertical Collapse

    That looks pretty good to me. These monitors were never perfect, but our eyes have become used to the perfect geometry of an LCD. Tilting the yoke affects both the bowing of horizontal lines as well as the convergence. You have to pick the best compromise. I'm not surprised the CRT was...
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    NeXT 400dpi laser printer restoration

    That looks like corrosion damage to me. That resistor isn't under much stress, and clearly has not been overheated. I would take a very close look over all the boards, and the motor board for more damage. A stereo microscope would help here. In my experience, a close visual inspection is...
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    NEC Multisync APC-H4311 and JC-1401P3A

    Since there are no retrace lines, I think we can rule out things such as excessive G2 voltage, or most of the video output/CRT drive circuits. I would test it with an analog (VGA) source. That would narrow it down to something to do with the TTL input electronics, or something after that.
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    NEC Multisync APC-H4311 and JC-1401P3A

    When you get a chance, post a picture or two of what's on the screen. We might be picturing something different from what you're seeing.
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    NEC Multisync APC-H4311 and JC-1401P3A

    These types of power supplies usually don't work properly without a load. I would try measuring the voltages with the power supply connected to the rest of the monitor.
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    NEC Multisync APC-H4311 and JC-1401P3A

    Page 30 has some advice on finding the cause of abnormal brightness. I would start there. In general, if the brightness is too high, either the screen/G2 voltage is too high, or the cathode voltage is too low.
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    Commodore 1084 Phillips Screen faint lines running off buttons, title bars, etc

    You obviously have to be very careful about where you discharge a CRT to. The service manuals generally say to discharge to the CRT shield, or external coating. Even using a HV probe grounded to the wrong spot is likely to cause damage to the electronics. Some early color TVs even had an...
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    CRT monitor color issue

    It could be magnetized, but the built in degaussing coil should take care of that unless it's malfunctioning. If someone was playing with a large magnet, then it is possible to magnetize it too strongly for the built in degaussing coil to fix it. If it was dropped, the shadow mask may have...
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    Commodore 1084 Phillips Screen faint lines running off buttons, title bars, etc

    I really wouldn't worry about damaging the CRT by discharging it too abruptly. Most service manuals even say to SHORT the anode to ground to discharge the CRT. This rumor about possibly damaging the CRT seems to be a somewhat recent Internet myth that has been passed around for the lat few...
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    The longevity of vintage computer displays

    Nothing has an unlimited service life, but that's not really an issue. CRTs have a typical service life of at least 15,000 hours, and better specimens can last much longer. If only used for a few hours a month, or a year they will last almost indefinitely. I personally own some CRTs that are...
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    The longevity of vintage computer displays

    I've started to see "LCD vinegar syndrome" happening more frequently than I'd like. While it can be repaired by replacing the polarizing films, it's difficult to do without damaging anything else, and almost impossible to avoid introducing defects like dust and air bubbles. Plasma displays...
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    CPD1604S Vertical Collapse

    Errors on schematics are common, so always double check things. I've also seen errors on circuit boards. I make a habit of checking that the board is labeled correctly before I remove a capacitor.
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    CPD1604S Vertical Collapse

    Yes, 2SC, and 2SD are always NPN. 2SA, and 2SB are PNP. In general, for low power circuits like this transistor substitutions are fairly easy. Just get something with equal or greater voltage, and current ratings. Gain shouldn't matter too much as long as it's not wildly different. As you...
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    CPD1604S Vertical Collapse

    Whenever leaking capacitors and corrosion are found, any other problems are almost always directly related. I would go over the board again, looking for open traces, or damaged components. Sometimes it even gets inside ICs and causes them to fail. Also, make sure nothing dripped down onto the...
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    CPD1604S Vertical Collapse

    It would be helpful if you'd post some actual screen shots (ideally showing a grid pattern). There might be something subtle in the image that would give one of us an idea.
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    Anyone here also work on VCRs?

    Ultimately, the output from the sensor should be a binary value, so easy to see if it's working. I would start with possibly replacing the photo diode since I've seen those go out of spec before. I would resist the temptation to change resistor values since you'll just be masking another...
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    Anyone here also work on VCRs?

    If it works with the sensor covered, what's the problem? When the VCR is assembled with a tape in, the sensor is covered by the tape. If the end sensor is still being activated, then there's a real mystery since the IR LED should be the only source of light. I have occasionally seen end...
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    IBM 5154 Enhanced Color Monitor Rejuvenation

    Your symptoms sound like an electronic fault, not a bad CRT. CRTs generally fade out gradually over years, and don't come back intermittently. Occasionally shorts can develop inside the electron guns, but that usually causes the affected gun to turn on full blast. To be sure, you need to...
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    CRT repair help

    Convergence is affected by the focus and HV. It's normally not very noticeable, but when things are way off, it becomes obvious. The lack of focus is the most concerning symptom I can see. Normally, the HV and focus voltages track each other so that even if the HV is too low, or too high...
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    CRT repair help

    Well, something is obviously causing the HV to be too low, and appears to be affecting the horizontal blanking, causing that black bar in the picture. Since the B+ voltage to the flyback is correct, and there's no direct HV regulation, it doesn't leave a lot of possibilities. I see a signal...
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