View Full Version : Tube Tester question


jstout66
05-20-2004, 03:58 PM
Can you guys help me out on this one? I have a B&K 667 tube tester which has never given me problems in the past. When I get a tv or radio, I test all tubes and replace any weak or "shorted" ones before I proceed with anything else. Currently I am working on a Sylvania "roundie" that has no color. (the color "rainbows"). I had 2 bad 6GH8's in the sync section and 1 bad 6JU8 which is a color killer / sync tube. Anyway... Got my tube order today, and I tested the tubes. Both 6GH8's were good, BUT... both 6JU8's had a dead short in the same position on the tester. I suspect I did get 2 bad tubes, but how common is that with N.O.S. ??? Would you try the tubes in the set to see if it works? I didn't want to put in a shorted tube in case it caused further problems. Have you run into a tester where it will test the same tube tybe as "bad"? and what do you think of B&K in general?? Thanks!!!!!

kc8adu
05-20-2004, 06:58 PM
read the setup book.
look for a symbol before or after the settings.
the short may be normal with this tube.

jstout66
05-21-2004, 06:49 AM
nope.... it doesn't say that is normal. One of the tubes shows a slight flicker in "E 2" position the other makes the short light come on like a high-beam headlight! I'm going over to where my set is stored tonight and will test the "old" tube, and see if it showed a short in that position as well. I'll replace the 6GH8's in the sync section and I'll try one of the suspect 6JU8's and see if that restores color to this tv. When I tested all the tubes I was sure when the 6JU8 tested bad that that was my problem....

Chad Hauris
05-21-2004, 07:10 AM
You may be able to replace those 6JU8's with silicon diodes...the later versions of those sets did.

jstout66
05-27-2004, 07:22 PM
I just wanted to give you all an update and a reminder. I tried both of the NOS 6JU8's in my Sylvania roundie, that my tube tester showed a dead short in the same position, which kind of gave me doubts about my tube tester. . . I still had color bars but the color would lock in if I "de-tuned" the set a bit. I contacted my tube seller and he was great and sent 2 more out at no charge. The tubes that arrived were a different brand. 1 tested fine, and the other showed a short in the SAME position. I tried the one that tested fine, and the color was perfect!!!! Locked in and no color bars. So...... my reminder to you is that you should test ALL tubes in your sets to eliminate any problems, AND test the NOS ones that you purchase from your provider. Just because they are new, don't assume that they are good. I won't doubt my B&K in the future! By the way.... were 6JU8's known to be crappy tubes?!?