Museum Hours:

Saturday 10-6

Sunday 12-5

Early Electronic Television

  General Electric HM-225/226 Technical Information

Television: Five channel (50-90 mHz) superhetrodyne. HM-225: 9 inch CRT.  Electrostatic focus, magnetic deflection, approx. 45 degrees. HM-226: 12 inch CRT. Electrostatic focus, magnetic deflection, approx 50 degrees.

 

Function
Quan. Type
Notes

TV Chassis   

Oscillator/Mixer 1 6F8
Video IF amplifier 2 6AB7 Video (9.5-12.75 mHz), audio (8.25 mHz)
Video IF amplifier 2 6AC7  
Video detector 1 6H6
1st video amplifier 1 6F8
Video output 1
6F6
Horizontal (line) oscillator 1 6N7
Horizontal (line) output 1
6AL6
Vertical (frame) oscillator 1
6F8
Vertical (frame) output 1
6V6
Audio IF amplifier
1
6SK7 8.25 mHz
Audio IF amplifier 1 6B8
Audio detector, amplifier 1 6SC7
Audio Output
2
6V6
Rectifier (HT)
2
5U4
High Voltage (EHT)  1 2X2 4000 VDC

Radio Chassis (HM-226)

RF ampifier 1 6SA7  
IF amplifier 1 6SK7 455 kHz
Detector/AVC 1 6H6  
Audio amplifier 1 6SF5  
Audio inverter 1 6J5  
Audio output 2 6Y6  

Service manual

Technical information