1955 Motorola 17T20

[dieseljeep]

Originally Posted by maxhifi

This looks like the American cousin of the Marconi I'm working on right now, 17" series string set, with a half wave selenium rectifier? What picture tube does this one use? Look forward to following this project.

Even though, it's not my set but I know it enough, from experience. It uses a 17HP4 CRT and a voltage doubler for higher B+. The tubes are in a series-parallel configuration, where the set you have is a newer model, using only one 600ma series string. That's the way, the US designed sets progressed to.
Yours is very similar to the US designs.

[maxhifi]

Originally Posted by dieseljeep

Even though, it's not my set but I know it enough, from experience. It uses a 17HP4 CRT and a voltage doubler for higher B+. The tubes are in a series-parallel configuration, where the set you have is a newer model, using only one 600ma series string. That's the way, the US designed sets progressed to.
Yours is very similar to the US designs.

You nailed it there, I don't want to throw this thread too far off topic, but it would sure be interesting to understand the progression in circuit design from the RCA 630 to say, the Philco Predicta or maybe a bit later.