View Full Version : blue line through the middle of the screen?


charokeeroad
06-26-2011, 09:35 AM
Does that mean that the CRT is good.

http://losangeles.craigslist.org/ant/atq/2446718400.html

VintagePC
06-26-2011, 09:37 AM
I suspect it means the vertical is gone - CRT is "good" in the sense that it works, but might be gassy, or have low emissions etc - can't tell without a tester.

charokeeroad
06-26-2011, 10:46 AM
I'm close to Palmdale, I think I'll check it out... and bring along my tester.

Thanks

Tom Albrecht
06-26-2011, 12:08 PM
If the blue line is very bright -- to the point that it practically has a "halo" around it when the brightness is turned up, that is a good sign. Basically when the picture is collapsed to a single line, the line brightness should be pretty excessive if the tube has good emission. Best not to run it too long in that state since it can damage the phosphor, but it is a reasonably good indicator of good emission.

miniman82
06-26-2011, 12:18 PM
Even an almost dead tube will show a bright line if vertical deflection has failed, since all the emission is in one line vice spread out across the whole screen.

jr_tech
06-26-2011, 12:38 PM
I'm close to Palmdale, I think I'll check it out... and bring along my tester.

Please don't make the mistake that I made once ... the heater voltage of the 17DRP4 is 2.68 Volts not the usual 6.3 Volts.
jr

charokeeroad
06-26-2011, 05:53 PM
Please don't make the mistake that I made once ... the heater voltage of the 17DRP4 is 2.68 Volts not the usual 6.3 Volts.
jr

Thanks for the reminder .. I'll be careful.

I've tested several of these CRTs over the last year or so and haven't found a good one yet. Maybe this one will be good..