Re: HP 853A - no CRT display at all - troubleshooting help needed
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I had a 853A CRT slowly lose its vacuum.? The deflection amps roasted as
the current increased until the tube no longer showed a picture/trace.? -J-
-----Original Message----- From: "David Feldman via groups.io" <wb0gaz@...> Sent: Thursday, October 8, 2020 11:59am To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 853A - no CRT display at all - troubleshooting help needed
So far - no hint of a glow, even in complete darkness. There's no beam finder control; there are position trimpots on the front which didn't bring anything into view. Verified (with power off) filament continuity (temporarily disconnect filament lines from HV board to CRT). No sign of residual light during power down. Also, sometimes when I turn on old-style oscilloscopes I hear a "crackling" sort of sound (as the HV comes up); no sign of this here. Status LEDs are lit except for the LED reflecting the 158V output of the display section power regulator - the test point where that LED is located is showing ~168V (supposed to be 158V.)
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