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

[k4pf at juno.com]

> John King <k5pgw at yahoo.com> wrote
>Subject: [Test-Equipment] technical consultation needed for B&K 700 -
> 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. <snip>

Hi, John

Your problem might be C-1, a 250uF 6V electrolytic across the panel meter.  If that is leaky, the meter sensitivity will be reduced.

Also, there are two types of "83" rectifier tubes, the 83 and the 83V,
both of which are 4 pin types.  I believe you need the mercury vapor 
type 83 (no V suffix) in order to get the full 200VDC at the center tap of the 83 tube heater winding when the Gm button is pressed. 
That 200VDC is measured at the white/blu winding
near the top of the transformer schematic. 

73,
Ed Knobloch