Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: Mauzy on December 12, 2007, 08:51:13 pm
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Hey everybody.
I have a G07 that was bought in a junked cocktail table. The tube was backwards and all cables were cut. I reconnected everything, and saw some sparks. Crap. I bought a new set of chassis with a new cap kit preinstalled, and it works fine, but it takes about a minute to a minute and a half for the picture to come up on the tube. I don't know how long the tube sat without being used, but it had the heaviest Galaga burn I had ever seen.
Is it normal for it to take this long to come up?
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a weak crt will take some time to display a pic.
a strong tube should have a pic within 10 - 15 seconds ...
sometimes a rejuve procedure may help for awhile .
phosphor burn can not be fixed short of replacing the crt :'(
qrz
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The burn doesn't bother me when the game is on. A piece of smoked plexi fixed that.
How does one rejuvenate a tube?
Do you think this is a case of a tube not being used for so long that it has weakened, or just a case of a 24 year old monitor being a 24 year old monitor?
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sencore made a couple of models that do a nice job . i think b&k may have had some as well.....
seen some sencore on ebay for far less than i pd new in '84 :'( ( cr70 )
a weak tube can be compared to a mineral build up in plumbing. the more gunk in the pipe the lower the flow.
a weak crt has less available electrons in which to bombard the phosphor. the greater the kinetic energy of the electron impact, the brighter the emited light ( hence the high 2nd anode voltage )
what the rejuve procedure involves.. briefly increasing the filament temperature by applying a higher than normal
voltage . this will increase the volume of available electrons at the cathode .
a momentary high positive voltage is applied to g1. the sudden presence of the voltage attracts the electron cloud from the more negative cathode . the sudden burst of current ( limited to 100-150 ma ) will burn off a layer of cathode "crud" thereby restoring normal beam current. however.......,
cathode material has a finite life. eventually, the emitting material will be depleated . nothing further can be done short of replacing the gun assembly . this is called a rebuilt tube .,or grade B crt
tubes generally will not degrade from disuse.
sorry u asked ? ;)
qrz
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Hmm... sounds interesting. Thanks for the great info.