Motorola 9T1
 

I purchased a 9T1 from an ad on EarlyTv.org. Would anyone have a complete scan like the one that I've attached? I'd like to print one out to use.

I knew the bakelite had some cracks before I purchased it. It appears to have been well packed, but it arrived in many pieces. :tears: I'll be busy working with a jig-saw puzzle. :scratch2:

One section of the ballast tube is bad. I could repair the break. I also thought about rebuilding it. Does anyone know what alloy was used for the resistance wire? Rider shows the cold resistance, but I'm not sure what it would be in operation.

One reason I might not want to rebuild it is something I read from amperite. They list ballast lifetimes of 2,000 to 5,000 hours.

I suppose I should check the 8BP4 before I put much effort into this.
John

http://www.antiqueradio.org/motvt73.htm

Phil describes building a whole new ballast tube from modern power resistors.

I just finished restoreing one of these, only in fabric covered case. I replaced the ballast with power resistors as detailed on phils antique radios web site. a great site for anyone restoreing radios or tv.

I just noticed a sticker under the tuner wafer switch that says: "Do It Right"

Anyone seen one of these? Was it meant for the factory workers or repairmen?

I've read about using resistors. I'm not anxious to do that. I might design an active regulator if I can hide it.

I guess the premise is that with today's infrastructure we don't need to worry about voltage swings. When I upgraded my house to 200amps from 90amps service I thought the power company would replace the lines to the service entrance with a more appropriate gauge. They didn't. I don't remember the gauge, but it's about 3/16" diameter aluminum. That wouldn't matter except it's about a 50 foot run. That runs to lines that I might consider using for jumper cables. They run 200 feet to a transformer with about four other houses on them. The birds enjoy warming their feet on them in the winter.

I have a Majestic 71 receiver. Even with the ballast I definately notice my refridgerator starting. Without AGC it's sensitive to line variation. I also have a lamp with a carbon filament that like to use in the evening. With carbon having a negative coefficient of resistance it's quite sensitive to voltage swings. It's interesting to watch the lamp at times.

The upshot is that I don't have stable line voltages.

Maybe I shouldn't care, but I like to keep things as original as possible.

I know that they used iron wire in hydrogen filled tubes, but it seems unlikely that they would use iron in air. I thought perhaps nickel. NiCr is meant to have a stable resistance which wouldn't help regulate much. If I knew for certain that they used Nichrome I'd just use power resistors.

John