Sylvania Dualette resto.

[Electronic M]

Anyone else here ever wondered what is inside a Dualette?



I finally had some bench time yesterday, and decided I wanted to start by giving this a turn on the variac. It came up with a loud hum in the audio and a raster with a lot of spacing between each scanline....However that raster was only visible while turning the brightness knob.

Pulling the back and checking the CRT revealed a rather healthy CRT and that most of the tubes are original Sylvania. Also many of the paper caps on the main board were replaced by Sprague labeled yellow film caps similar to the yellow film caps commonly used by the radio community in restos presently.



As I figured, an afternoon recap session was all it needed to bring it back to life. I did leave one 2uF 50V lytic in the sound, but it does not seem to be adversely affecting anything. The recap was fairly straight forward, though some caps on the main board needed the vert out trans unmounted to get at them and a few caps on the board had their traces partially blocked by the mounting frame rails making access without removing the board tricky. The sweep section of the chassis is also a bit cramped to recap, but would have been easier if I had warmed up a smaller iron.



Post recap I took it completely apart, hosed the dirt out, cleaned the safety glass/CRT face, and scrubbed the cabinet. Once it drys enough to power up again I'll adjust the yoke and centering, reinstall the back and call it done.

It has very good sound for a portable with a single ~2" speaker. I'm also somewhat impressed how light it is for a 17" series string set. I like the engineering in this set. The chassis is held in by 2 screws at the top and slide tracks at the bottom with spring grabs to help hold it. It is also cool how the speaker is retained by a single spring clip at the back. They did a good job of protecting the CRT neck too...The entire neck is recessed a bit behind the chassis frame such that you would have to pierce the back dead center with something fairly small to have a shot at necking it. One thing I find weird is that a set with 3 IFs would extend the AGC out to the back and give it it's own user knob...I'd love to find a schematic to see if there is some electrical reason for it.