CurtPalme.com Home Theater Forum

[Tim in Phoenix]

Guys

I was trading e.mails with someone last week, and he found this helpful:


Tubes need all of these things to light up properly:


Vacuum in the tube
Look for cracked tube face and lit filament in the gun (filament would burn up if air gets in)


G2 bias voltage ~550 vdc Measure on neckboard tip of R76
Origin-high voltage power supply


Anode voltage 34.9 kv Need HV probe to measure at HV splitter--listen for crackle at power-up instead
Origin-high voltage power supply


Video signal into neckboard 1/2 volt
Origin-VIM input section----mini coax to neckboard


Video signal to electron gun 80 volts Will see if measurable with voltmeter on the neckboard. Signal
is inverted; 80v is black.

Origin-neckboard, drives a pin on the electron gun----swap neckboard with a known good one
or check with oscilloscope


Filament voltage 6.3 vdc Measure at MB P14 connector, problem if over 6.5 vdc, will ruin the tubes
Origin-low voltage power supply

If everything measures good but filament is high, good chance that the plating has boiled off of the cathode and the
electron gun is dead---replace the tube.







I have compiled this and some other information in my Marquee by Voltmeter Doc.

E.mail me if you would like a copy.


ehometech8022@yahoo.com


Tim Martin, E-Tech Systems Scottsdale, your Marquee Pro Shop

480 253 2781 please text me first




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