View Full Version : Testing: 3KP4 vs 7JP4 on Sencore CR70


Phil Nelson
07-27-2009, 07:18 PM
I just got a Sencore CR70 CRT tester and have been happily testing everything in sight, except my single 3KP4 for which no settings are given.

This tester has a universal adapter with little clips that you connect to CRT pins for heaters, grids, etc. Works fine to test a 7JP4.

I have seen oldgoat's Youtube video about testing a 3KP4. Seems like all he did was build an adapter cable for the CRT.

http://www.youtube.com/watch?v=wZH-nRMSnPw

Is there some technical reason why my unit can't test a 3KP4 or did Sencore omit 3KP4 from their chart simply because it was so little used?

http://scottbecker.net/tube/sheets/049/3/3KP4.pdf

http://scottbecker.net/tube/sheets/137/7/7JP4.pdf

I'd like to check the 3KP4 in my Pilot TV-37, but it's the only one in the house, so I'm leery of rash experiments.

Phil Nelson

bandersen
07-28-2009, 06:57 PM
I love those oldgoat videos :)

The 3KP4 seems to have lower recommended operating voltages than the 7JP4 so I'm thinking the test results won't be valid. Anode voltages are a lot less too.

Does the Sencore put out high voltage to the anode or just test the emission?

mbates14
07-30-2009, 10:52 PM
too bad the guy lost his workshop. i feel sorry for him, too bad i didnt live closer, i would help him move and setup.

Phil Nelson
07-31-2009, 02:59 AM
Does the Sencore put out high voltage to the anode or just test the emission?
No HV, just an emission test. It also test shorts, cutoff, does life test, rejuvenate/restore, etc., but what I'm most curious about is emission.

Phil