Roberts Valve Tester

[Dave Simpson]

            Thanks Mike for your reply. I'm afraid that both Roberts are beyond redemption, and are presently being incorporated into a hybrid project. Roberts' idea of examining a valve's voltages whilst in-situ in the original radio is an interesting one, but their circuitry was flawed. They have no internal power supplies, and no method of determining Gm. Hopefully, my hybrid will remedy that.
      Right enough, AVO & other VCM's & Valve Testers rely on 20mS half-wave pulses to determine mA/V. Having repaired & maintained RAF CT160's back in the '60's, and more recently owned a couple plus a MK3, I'm afraid I'm guilty of boring the pants off VRR&R Forum folk, over a number of years, with heaps of "Banging-On" thread posts. So will refrain from annoying chums on this Golborne Site.
       I've put out a heap of pictures on the VRR&R (Test Equipment) Forum relating to the Roberts Hybrid, but will add some here. Basically, the hybrid uses a trusty AVO 8/6 for Voltage & Current measurement, a series of latched on-off-on toggle switches in-lieu of an AVO's great Thumbwheel Switch, and several salvaged Roberts' wafer switches for choosing the test functions.

                                                                               Regards,   Dave