Early Electronic Television
HMV 904/905 Technical Information
Television: Single channel superhetrodyne. 45.0 mHz video, 41.5 mHz audio. The 904 uses a 5 inch CRT (Emiscope 3/1) triode and the 905 uses a 7 inch CRT (Emiscope 3/2). Magnetic focus and deflection, approx. 45 degrees. |
Radio: Short (16-52 meters), Medium (200-550 meters) and Long (750-2000 meters) wave bands.
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| RF amplifier | 1 | MSP4 | |
| Oscillator/mixer (frequency changer) | 1 | X41C | 37 mHz local osc. frequency |
| IF Amplifier | 1 | KTZ41 | Video (5.5-8 mHz), audio (4.5 mHz) and radio (456 kHz) |
| IF Amplifier | 1 | KTZ41 | Video and audio |
| IF Amplifier | 1 | KTZ41 | Video only |
| Video detector/amplfier | 1 | MS4B | |
| Sync separator | 1 | KTZ63 | |
| Horizontal (line) oscillator | 1 | KTZ63 | |
| Horizontal (line) output | 1 | KT63 | |
| Vertical (frame) oscillator | 1 | KTZ63 | |
| Vertical (frame) output | 1 | KT63 | |
| Audio detector and AVC | 1 | MDH4 | |
| Audio Output | 1 | KT41 | |
| Rectifier (HT) | 1 | U52 | |
| High Voltage (EHT) | 1 | U17 | 2500 VDC |