? on testing a crt

[azbigsam]

I have a Sencore CR161 and trying to test a 21EAP4 from a Predicta. When I set the filament voltage to 2 it jumps all the way up to 3 on the voltmeter even with the fine adjust all the way down?? When set at 1 I'm not able to adjust it all the way up to the 2.34 that I need. Would it be OK to test at 3v or is that too high. Hope this made sense!

[old_coot88]

Originally Posted by azbigsam

I have a Sencore CR161 and trying to test a 21EAP4 from a Predicta. When I set the filament voltage to 2 it jumps all the way up to 3 on the voltmeter even with the fine adjust all the way down??

Is this the no-load voltage? If so, it may come down to the proper value with the CRT connected.
Try 'blipping' the tester on for justa second with the CRT connected and see.

[walterbeers]

Most CRT testers are designed for 6.3volt. I'm not sure if the Sencore CR161 will accurately set to that low of a voltage. (never used one) Yes, try it on another CRT and see if you can set the voltage to the 2.3 volt with it connected. Might be a dirty, or bad control in the CR161, or maybe you have an open filiment or loose connection at the pins of the 21EAP4 Check the CRT pins for continuity with an ohm meter. My Beltron CRT tester will vary the voltage all the way from 0 up to 15 volts. Not sure about the Sencore.

[zeno]

If you have the universal adaptor put a maybe 10 ohm
5W resistor in series & adjust for 2.3 VAC on the filament pins.

73 Zeno