Note
QST, Jul 1946, p. 158.
Millen catalog, 1947–1948
QST, May 1955, p. 158.
Millen catalog, 1959
The 90900-series scopes were basic rack-mount units that could be used for transmitter monitoring. They came with a power supply and controls for brilliance and centering. The last digit in the model number indicated the scope tube size.
90902 – 2 inch scope
90903 – 3 inch scope
90905 – 5 inch scope
These scopes do not contain sweep generators or amplifiers, both of which were subsequently sold separately. So out of the box, they are adequate for transmitter modulation monitors, and not much else.
The 90905B is an up-rated version of the 90905, and was sold concurrently. It uses a flat-faced Dumont 5ADP1 tube for improved sensitivity and focus.
Specifications
-----------------------
90902
– DC supply volts: 800
– Plate volts: 705
– CRT: 2BP1
– Rectifier: 2X2-A
– Deflection
Vertical: 36 volts RMS per inch (100 volt peak-to-peak)
Horizontal: 43 volts RMS per inch (120 volt peak-to-peak)
90903
– DC supply volts:
– Plate volts:
– CRT: 3KP1
– Rectifier: 2X2-A
– Deflection
Vertical:
Horizontal:
90905
– DC supply volts:
– Plate volts:
– CRT:
– Rectifier:
– Deflection
Vertical:
Horizontal:
90905B
– DC supply volts:
– Plate volts:
– CRT: 5ADP1
– Rectifier:
– Deflection
Vertical:
Horizontal:
All versions operate from 115 VAC, 60 Hz.
90902 – 19 watts
90903 –
90905 –
90902 – 3-1/2 in. high, 8 in. deep
90903 – 3-1/2 in. high, 13 in. deep
90905 – 7 in. high, 18 in. deep
