Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Mon Oct 28, 2019 1:49 pm Post subject: Some troubleshooting tips for Marquee, one color not on |
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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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