Found something interesting in the video output circuit on the tv400. Both the riders and my set show the 1meg resistor from the grid of the 6au6 video output tube going to the contrast control and through the wiper to ground. The SAMs shows the 1 meg resistor going straight to ground.

The way it's connected the contrast control controls the cathode and grid of the tube. So it makes sense that when its low you will also have low volume and sync output? The SAMs shows the resistor connected to ground and changing the contrast control will not affect the grid of the tube.. Should I modify my set to show what SAMs says it should be?

I'm currently going through the resistors in my set to cure some issues that recapping didn't fix. Got a double image vertically and you can see the flicker of the scan. I assume that's running slow. The horizontal is causing me the most trouble. As the set warms the oscillator drifts for about twenty minutes making me adjust it every minute. Horizontal and vertical lock are also very touchy. I'm currently going through the SAMs and organizing my replacement resistors for the video output, sync output and horizontal and vertical oscillators.

Any advise on anyone's issues with working on the sentinel tv400?
Thank you! Matt Davala.

Odds are there was a production change. One schematic represents pre-change the other post. Sam's also is known for having a generous smattering of typos and errors in it's various folders over time, so never take a sam's difference from factory wiring too seriously.

I'd leave the original wiring configuration as is.

I assume you replaced all the paper & lytic caps. Resistors is a good next step, but don't forget to change the deflection/sync stage mica capacitors....Deflection/sync stages put much more strain on mica caps than other stages, and thus micas in those circuits are prone to fail.

Yes I have already caught a few errors in the SAMs. As for replacing mica caps, there are none in the tuner chassis. All ceramic, except for the paper and electrolytics.. I'll pull the deflection sweep chassis later and check for mica caps.

Thank you!

You're welcome.

I recommend that you don't replace micas in tuner or IF stages unless you know for a fact the cap your changing has failed. The tuner/IF sections are much gentler on the micas, and they almost never fail in those circuits. Also if you change mica caps in the tuner/IF stages you will likely need to realign the set.... TV alignment requires a lot of specialized, costly, complicated, accurate equipment and skill/practice, and is something you want to avoid.