Restoration of the DuMont Industrial Color Monitor


Posted on Feb 5, 2014

There is not a coaxial input to the motor control chassis, so I doubt that composite sync was fed to it (cables would be 5 or 6 feet long), which might rule out a sync pulse for the red field. Some other interesting things. The CRT has the pin type anode connector that DuMont used in the late 40s. That means the tube was a 12J or Q probably. There are two flybacks -


Restoration of the DuMont Industrial Color Monitor
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one for horizontal sweep and one for HV. It will be interesting to see how high the HV is. The video amp uses parallel 6BG6s as ouputs. I guess they needed it to handle 18 mHz The power supply is a monster, with two regulated B+ outputs. I will be posting schematics as I get them done, starting with the video and vertical sweep chassis. Today I finished documenting the 3 chassis and everything fell into place. I am still trying to figure out what kind of horizontal oscillator transformer was in the set. It plugged into an octal socket and I think it was wired like this. I think there were 3 windings on it, and since it will be difficult to find a 3 winding transformer, I will try and modified circut, also shown on that link. That schematic is very similar to the oscillator used in the HV section of the DuMont Royal Sovereign, which was from the same year as this monitor. I have replaced all the paper and electrolytic capacitors. Everything seems to work - HV is 15 KV. I used a standard horizontal blocking oscillator transformer, and it worked fine at 46 kHz. Since I don`t have a signal source yet I`m not sure how the sync will work. Cliff Benham has the wheel, and is building a replica. He has also volunteered to build a motor control circuit, which will be locked to the power line. Here is the schematic of the CBS slave receiver motor control, which he intends to duplicate: I looked at how the motor control would work if...




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