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I acquired a used IBM 5153 monitor. The model number is 5153002. It was manufactured in Taiwan and supports AC100-250V.

enter image description here When I first powered it on, the monitor turned on, but nothing appeared on the screen. (Literally, there was no light coming from the screen.) After adjusting the SCREEN knob on the FBT, the screen finally lit up.

enter image description here When I connected the monitor to a CGA card, something appeared on the screen, but it was not normal. By adjusting the V Hold knob, I was able to stop the vertical movement of the screen. However, the content on the screen was vertically overlapping.

enter image description here enter image description here enter image description here I wanted to fix the issue by adjusting the V Size knob, but it seems this monitor is missing the V Size knob.

enter image description here enter image description here Additionally, I ran Checkit to check if the colors were displaying correctly, and there were several issues.

I have no knowledge about CRT monitors. How can I resolve the following issues?

  1. Correcting the vertically overlapping screen
  2. Restoring the incorrect colors to their proper state
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    Interestingly, you get a non-overlapping image in the "graphics mode" test screen. The vertical CGA sync signals should be identical in text and graphcis modes, so I wonder whether your CGA card is outputting spurious sync pulses in text mode. Regarding the color: The image looks you might have a short between the "R"ed and the "I"ntensity line. It's not obvious whether the fault is in the graphics card, the video cable or the monitor, though.
    – Michael Karcher
    Commented Jun 6 at 23:05
  • You can see that the image overlap vertically even in the graphic mode test screen.
    – Sung
    Commented Jun 7 at 3:02
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    "I have no knowledge about CRT monitors." Hopefully you know that there is very high voltage inside, enough to easily kill you. And it can take quite some time to discharge to non-hazardous values.
    – Ralf Kleberhoff
    Commented Jun 7 at 13:43
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    @RalfKleberhoff Just to add, it is also very easy to damage the monitor as well as yourself if you do not know what you are doing (I have personally done this). The recommended advice is to 1) leave such a job to a professional or 2) at a minimum, understand what each of the basic monitor components is/does and which leads carry high voltages. Some old monitors can store charges for a long time. Also, be very careful about making accidental contact between any two components.
    – Noel Whitemore
    Commented Jun 7 at 15:49
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    @Ralf Kleberhoff, Noel Whitemore Thank you for your advice. So far, I have been lucky not to get shocked. I discharged the tube using an alligator clip and a screwdriver, but I’m not sure if this completely prevents electric shock...
    – Sung
    Commented Jun 7 at 16:35

1 Answer 1

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I ultimately solved all the issues.

I had the following the following issues:

  1. Correcting the vertically overlapping screen
  2. Restoring the incorrect colors to their proper state

The 2nd issue was simply a poor connection, which could be resolved by using a contact cleaner.

To solve the 1st issue, I had to carefully adjust several pots on the monitor, and it was crucial to know which ones to adjust.

enter image description here enter image description here

What I considered important in the troubleshooting process was identifying the names of the pots. The resistors related to vertical adjustment started with VR3, and those related to horizontal adjustment started with VR6. Here is a brief documentation:

VR303 - V Size VR304 - V Hold VR305 - V Position

In conclusion, I successfully obtained the correct display by carefully adjusting the VR304 and VR305 pots.

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