Bruel & Kjaer 2409 Tube Voltmeter

[PeiCB]

Howdy

Is there anyone who has disassembled the B&K 2409 in order to de-solder and test the pcb-mounted electrolytic capacitors and resistors?
Like to disassemble as little as possible but I guess I need to be able to flip the top pcb over...?

All help and ideas are most welcome

[dejv]

Hi PeiCB.

Maybe you already have solved it, but if not, here's a few hints from when I faced the same challenge.

I have partly disassembled my 2409 to replace the electrolytic capacitors, several of them showed significant leakage. Apart from unscrewing the circuit board closest to the front panel, it was necessary to unscrew the knob assemblies to be able to reach further into the meter. Both from the front panel, and the by the small nuts attached to the threaded rods on the main PCB. The purpose of that is to access the solder side on both of the boards.

With that "part disassembly", I could keep everything still connected (with some exceptions, input jack for example). I then managed to replace all the electrolytics with NOS reformed axial types from Philips.

To successfully replace the axial caps between the "twin-board assembly" at the switches, I removed the old ones by cutting out the capacitor, then desoldered the legs and cleaned up the soldering pads with desoldering wick. Then I trimmed down the legs on the new caps to have 5 mm extra on each side, and slided them in place before soldering.

I also took the time to measure the resistors in the attenuator section, and they all performed within tolerance.

After a calibration, the unit performs beautifully. Well according to spec.