7" Airline porthole
 

I've been wanting a porthole set for years, I always figured I'd find a Zenith first, but I picked up this Airline instead. It's a cool looking set, trapezoid shaped, wider on the bottom than the top. It's a 7" electrostatic set that uses 2 separate chassis, the bottom one has the power supply, tuner, IF, video, sound - the one on the side vertical, horizontal, HV. I'm not yet sure what that button on the front labeled "telephoto control" does. The cabinet really needs cleaning, what works good on these vinyl covered cabinets? pictures below...

Murphy's Oil Soap ? I think the "Telephoto" button is kinda like a "Zoom" control-it magnifies the image displayed by 1.5X or somesuch.

Cool set Adam, it's a rebadged Sentinel except the Sentinel isn't a Porthole and doesn't have the Telephoto button.

It'd be interesting to see the circuit for that button when you get a schematic.

Second the Murphys Oil Soap.

I think I have the schematic for this if you need it.

Here's the schematic at that zoom switch, it calls it an "expander switch".

I'm thinking that the switch allows you to make a small rectangular picture (with blanks top and bottom) or to fill the round screen and lose some of the picture at the edges.

There's some surface rust ontop of one of the chassis. What's worked for cleaning rust off chassis? I don't want to use steel wool, because I can see little metal bits getting in everything. I also don't want to use really rough sandpaper or a wirebrush that would put really visible scratches in the chassis. Maybe a little wet sandpaper 240 grit or so? Or what else works?

I might just sand and paint those rusty tube shields, and repaint the power transformer, but I'd rather not paint the chassis itself.

I'd try Naval Jelly before you break out the abrasives. Give it enough time to work -- at least half an hour. Clean up with wet paper towels.

You may still have some discoloration, but it usually improves things. By coincidence, I'm using this on a rusty chassis right now (well, this week -- I'm slow and lazy).

You can follow up that treatment with metal polish, if you're the polishing type. I usually don't bother for TV chassis. Too many projects, too little time.

Phil

I'm just looking to get the rust off and clean it a bit, not really shine it up. I'll try that naval jelly first, and pick up some of that oil soap at the store at the same time.

I just went and shotgunned all the paper caps and electrolytics in this set. There was lots of really messy repair work on this one, and I just wanted a neater looking chassis where I could see what went where before I tried it out. There were some caps that were replaced long ago, with leads of the old caps just left hanging there going nowhere, or new leads that were just tacked into position. Also someone just went crazy with the corona dope, covering many leads and solder joints with big gobs of it.

I'm going to clean the chassis, test the tubes, and do a little more poking around before I fire it up. Luckily, there's no rust on the other chassis, or on the bottom of the one, and also the wires going to the speaker in that pic are the only rotted rubber wire in the set, mostly this set uses cloth, and the other rubber is in good condition.

That oil soap is working good, you can really see the difference.

Messed around with this tonight, made some progress, have horiz and vertical, but no picture or sound yet.

Problem was a bad oscillator tube, works now, but could really use some vertical retrace blanking.

Hey, that reminds me about this thread: http://www.videokarma.org/showthread.php?t=247230

I was just about to slide a VT71 chassis back into it's cabinet. No time like tonight to try that circuit out!

I used that circuit on my 2 VT71s and it worked for me, haven't been able to figure anything out yet for this set though.

This 1st pic shows what I did to remove the retrace lines. 2nd pic shows the blanking pluses going into the crt grid. Any thoughts, possible improvements to my modifications?