Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: jimmyjet on July 13, 2004, 05:47:08 pm
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I am working through Randy Fromm's repair flowchart. He says to check the regulated power supply at R1. "The terminal closest to the CRT should measure +120VDC." Using my DMM, what do I connect the leads to. I tried the red lead to the white wire on the resistor and the black to the chassis ground. Is this correct? I got 0 VDC. Please help a novice.
Thanks
jimmyjet
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Yes, that giant white resistor gets the "+" (red) meter lead and the frame ground gets the black meter lead. If you get zero volts then the small soldered-in fuse on the monitor is blown. When that happens, that large gray filter capacitor then holds a full 135 volt dc charge with no place to go! It packs a wallup if you touch it. With power disconnected and picture tube discharged, take the monitor board out and flip it over. Touch a 60 or 100 watt ordinary house light bulb across the + and - terminals of that large capacitor. The light buld will glow bright for about 2 seconds (it does NOT damage the bulb). That discharges that cap safely so you can work on the chassis.
If that little fuse is blown then the flyback and/or the horiz out transistor are bad.