I’ve compiled a list from information available on the internet that may help date a Hammond console (A-100, C3, B3, D-100, RT-3)
1958 – Vibrato line box changed from wood to metal
1960 – Side blocks change from wood to plastic
1961 – Pilot lamp added
1962 – Vibrato knob changed from smooth to ribbed (‘fluted’)
Mid-1962 – AO28 transformer colour change from silver to black
Spring 1964 – Start of using red caps
1965 – Hammond script changed from small to large with new logo
1965 – Foam replaces felt
1965 – Introduction of R/C (resistor/capacitor) networks to tones 37-48 to reduce hum and crosstalk
1969 – Drawbar plastic knob style change to have engraved tones
Additional information can be gleaned from the components in the organ. Speakers (A-100 series) are usually stamped with a production date; the same applies for tubes / valves as well as capacitors.
Here’s some information I found on the tubes / valves in Hammond consoles (A100-series, D100-series, B3, C3, RT3)
A0-28 pre-amp: 6X4, 12AX7/ECC83, 12AU7/ECC82, 12BH7, 6AU6 (2), 6C4 (2x)
A0-35 reverb-amp: 6X4, 12AX7/ECC83, 12AU7/ECC82, 12BH7, 6AU6 (2), 6C4 (2x)
A0-44 reverb-amp: 6CA4/EZ81, 6GW8/ECL86(2x)
A0-39 power-amp: 5U4GB, 12AX7/ECC83, 6BQ5/EL84/6P14 (2x)
An inside look at a Hammond tone generator. Shows the oiling system that uses cotton wicks, and explains and demonstrates the workings of the tone wheels.
Here’s a Hammond B3 / C3 User Manual in PDF format. The manual applies to both the B3 and the C3 equally, since the only difference in these models is the different cabinet. Much of it will also apply to the A-100 series Hammonds, which also have a power- and a reverb amp, not found on the B3 or C3, but use the same tone generator, pre-amp and other components as these models.
Mike Finnigan on Hammond. Nice bit of squabbling in the second part.
Hammond Documentary by the BBC featuring Keith Emerson, Steve Winwood and Jimmy Smith
Barbara Dennerlein – Jimmy’s Walk
Rhoda Scott – Moanin’ – 1972
Jimmy McGriff – I’ve Got A Woman (Parts 1 & 2). The video is a compilation showing shots of Hammonds and well-known Hammond players.