B&K 707 Tube Tester - Problem with emmissions test

[AmpFix]

I recently bought a used B&K 707 Tube tester. The guy told me he wasn't sure if it worked or not. I think he knew... but that's besides the point. The thing doesn't work.

The biggest problem I see is that even with no tubes inserted, when pressing the emissions test button, the dial goes all the way up, over the "120" mark. The shorts functionality seems to work. With no tubes, the shorts light does not come up but the dial does go in the "20" range.

I think that this means there's some kind of leak somewhere? A bad ground? How do I go about troubleshooting this thing?

[JHow]

How do I go about troubleshooting this thing?

Find schematic, start with power supply?


Here's an interesting article....

http://tubesound.com/2008/03/23/bk-707-tube-tester/

This guy has schematic and calibration instructions...

http://www.tone-lizard.com/B%26K_tub...nformation.htm

And more...

http://www.tone-lizard.com/Tube_Testers.html#B&K

Looks like lots of fun!!

[AmpFix]

The power supply looks OK. Heater voltages are also good, but with no tubes in, that shouldn't really make a difference, no?

[stokes]

Go over to Antique Radios - The Collector's Resource and post in the "Test Equipment Discussions" forum.There are some guys there that know a lot about tube testers.

[AmpFix]

Thanks - I'll try that. I cleaned all sockets and switches. I think that there might be one bad socket ruining it for all the others