[Test-Equipment] technical consultation needed for B&K 700

[John King]

Greeting technical folks. I have a nice B&K 700 tube tester. I have replaced the 83 rectifier tube, 6BN8 tube, NE 51 and NE 55 bulbs. I have also replaced C-4, C-5 capacitors and measured ALL of the resistors,which measured as they should.
All switches have been cleaned with De Oxit.
All tubes under test, including NEW tubes, test VERY WEAK  or BAD. They do not test shorted.
The test results are the same for sockets at the top  (for  popular regularly used) tubes AND   the sockets at the bottom in the lower tier..... ........BAD !!!
I am really puzzled by the poor performance of such a great tube tester. I have a feeling that it might be a result of something  I did  during recapping. I have checked the polarity of C-3 and C-4 that I installed and the polarity is correct and I made sure the # 51 bulb was the original type.  

I really need my B&K 700 to perform well as I am a boatanchor "nut" and I have many many tube transmitters and receivers.
Please walk through the schematic with me. I have a complete manual and need to determine the poor performance problem. Thanks for sharing your knowledge and experience with this very nice tube tester. 73, John, K5PGW