Ch 27x602-00BB Voltages on all 3 Cathodes of CRT are high, in the order of 190 volts. Similar chassis print shows about 135 volts. Acts as if screen control is turned too high but this voltage is ok (variable with screen control.) Sound indicates that channels are changing and video is scoped ok at output of video amp. Need suggestions, thanks. Tom
High cathode should turn the beam off, hmmm.... There is a control grid that connects to ground through a
1.5K resistor R5 or R25 depending on which CRT board you have. I've never seen one bad, but it's easy to check.Weak 200V supply commonly causes bright retrace (R460, D460, C461) but I'd have expected lower cathode voltages if that were the case.
Otherwise dunno - runaway high voltage, gassy tube, other?
Thanks for the reply. I dusted off my scope, and observed excellent signal pulses and the 3 color output trnsistors on the crt socket at the emitters. Went to the collectors, no signal pulses. Removed picture tube PC board and had very strong pulses on the collectors. I surmized from that the picture tube was bad. Tom
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