View Full Version : I've got a CRT tester! Questions too!!


leadlike
08-17-2008, 03:01 AM
Okay, I finally got myself a CRT tester-a sencore cr128. Now I'm pretty sure this is a bottom of the barrel model, so I don't plan to do any rejuvination with this...I just want a basic emissions tester for now. It came with a thick(ish) book, so I thought it was all there, but it turns out it is only the operating manual. I'd like to know if there is a source for tube charts. Another alternative is that I will be getting a copy of a GE crt manual which will have all the tube data I need. But how to I apply that to the tester? Specifically, I'm most concerned with the G2 switch which has three settings: lo 1, lo2, and hi.

From the manual: "G-2: this switch is used to select the proper B plus voltage to the G-2 electrode. Some tubes are designed to operate with the first anode potential of only 50 volts. Some later tubes have a G-2 voltage as low as 30v. If these tubes are tested in the lo-1 position, the emission indication will be above normal. An lo-1 or lo-2 G-2 type tube can be damaged if it is operated with the switch in the hi position. This is common to all modern crt testers and is set from the set-up chart."

So, pouring over the few tube data sheets that I have here, most give a G2 voltage of 300v. So I guess that would be "hi"? I just don't want to toast a crt with this thing...

leadlike
08-17-2008, 03:35 AM
Okay, bit of an update:

just opened it up, and found a diconnected electrolytic. Never a good sign. But I tested some possible trouble areas, and the only failed component I found was this electrolytic cap. Little wonder, as it is only a 150v unit and it is the input unit that takes all of the crap coming off of the AC lines.

I'm actually surprised to find that anyone was in here; as the tester looks (and even smells) brand new. Hopefully a cap swap is all it needs. I guess I shouldn't be surprised, though-this came from a flea market and it only cost a couple bucks. Just all part of the fun of getting what ya pay for.

andy
08-17-2008, 09:34 AM
...

eberts
08-18-2008, 01:48 AM
http://www.sencore.com/support/index.php?id=46