Working on a RCA KCS72M

[dieseljeep]

Originally Posted by bandersen

Quite often there is a mica cap inside the yoke across the horizontal coils. This set has a 91pF in series with a 1,000 ohm resistor.

Here's the schematic from Riders vol 10. There are several chassis revisions and this is the earliest. http://www.flickr.com/photos/70039806@N00/11598231834/

There's a bit of difference between the KCS72 and the KCS66, schematic as shown.
The KCS72 must be the el-cheapo model, that year.
I have two 21" consoles with that chassis. It uses the older type penthode tuner and a 21mhz IF strip, which was strange, as RCA was one of the firms, that changed to 41mhz IF's early on.
The KCS72 chassis used a 5U4 and 5Y3 rectifier, power supply, where the KCS66, used a selenium rectifier and voltage doubler power supply.
The KCS66 uses a 41mhz IF and a cascade tuner, plus four stages of IF.
The horizontal sweep should be very similar. Yoke is the same.
Spellcheck didn't like the tuner description, regarding the RF stage.