VOGONS


First post, by envagyok

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I have a philips xt pc (8088)
Sadly many of cables eat a mouse, so power supply rewired.
Now when i power it on only show at monitor a k character and a flashing "_"
I search over a net info's, and jumper settings, but not find any help.
Here is some photo from pc & motherboard:

I would appreciate any help.

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Reply 1 of 2, by mkarcher

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envagyok wrote on 2023-02-11, 06:05:

Now when i power it on only show at monitor a k character and a flashing "_"

This might just be a truncated picture, if the "k" is at the left edge of the screen. You might see the memory test running, displaying " 16KB Ok", " 32KB Ok", ...
It is normal for a memory test on an XT with 640KB to require around 30 to 60 seconds.

A truncated picture might be caused by a bad horizontal width or horizontal position control at the monitor (or a bad setting of a scan coverter like the RetroTINK). Do you still remember what graphics standard your system is compatible to (Hercules or CGA?). There is the possibility of MDA monitors with very basic deflection electronics (like the IBM 5151) to be damaged when driven with a CGA signal, so a bad hardware configuration could cause damage if left running for more time. There is a basic test you can perform on your monitor to find out whether it is as vulneratble as the 5151: Disconnect the video cable from the computer, turn it on, and set brightness and contrast to maximum. If you see a bright screen, your monitor is safe. If you monitor is a color monitor, it is safe, too. If nothing happens at all and the monitor is monochrome, you better check whether it is a monochrome CGA-like monitor (which should be safe), or a monochrome MDA/Hercules mode. In the last case (monochrome MDA/Hercules that doesn't show a brigth screen if not connected to a compture), it is recommended to check whether the video output of the PC is operating at 18 kHz horizontal frequency. The XT computer is likely to support both 18kHz MDA output and 15kHz CGA output.