ADVENT Videobeam
 

Got a line on one.. non working but apparently good CRTs.

Anyone have experience with them? Looks very cool

Back in the 90's I did contract work for the cat that bough out all
the Advent parts & service stuff. It put him into a $1,000,000 house
in a rich Boston suburb.
All the chassis I saw were either Sylvania or Electrohomes. I think
there may have been one more. They were modified console chassis
so easy to fix. Most of the failures were CRT's. You will need the
OEM screen that is curved. Otherwise it doesnt register right.
BTW all the stuff is gone now & his shop closed.

73 Zeno:smoke:
LFOD !

We had a Advent 750 in the 70’s. It operated well all the time we owned it. It had a built in cross hatch generator which had to be tweaked a few times during warm up. It was fun.

The below photo was in 1978 in my home in Wisconsin. You can see the faint outlines of the console and on top the first Artari video game system. You can also see the first generation JVC VHS VTR on the right, an original Sony KV 7010UA, on the left, SAE components, Marantz SLT 12 turntable and a Sony TC 850.

I have the original sales brochures and paperwork for anybody interested. I can put it on line for download.

https://visions4netjournal.com/wp-co...D7DBE35D0.jpeg

This is interesting.

I would very much like to see the brochure and associated info. That's wss a very nice setup you had back then!

Zeno: could you get service info easily for these, or did you have to find the sylvania/electrohome data? I dont see any Sams for them.

I will post a link here when the materials are online.

I think the one I am going to get is also a 750. All I need to do is find the time to pick it up now, the arrangement to get it has been made. Look forward to troubleshooting it and getting it going - I hope it doesn't need all the capacitors changed! Also, have been unable to locate a schematic or service info so far.

Advent supplied manuals & IIRC they were a cross between there
own & the chassis OEM. The Sylvania was the common 3 module
Super-Set chassis. The Electrohome was there one & only Canada
built solid state set. Both were very well built & used straight forward
design so very easy to fix. Tons of manuals came in the lot & probably
paid for his kitchen & several baths ! Hundreds of CRT's of all
3 colors sold out 100%. Add to that all the small parts & complete chassii
& you can see the $$ made.

I think this one is a 750, but won't be sure until I actually get my hands on it.

Do they use one flyback for all three tube?

Also, can these tubes be tested with a normal CRT tester?

Yes & yes

Thank you!

Got it home - It's not an Advent, but a Canadian made ELECTROHOME/ADVENT. It looks just like the Advent 750, but everything is labeled made in Canada. The screen has ELECTROHOME molded into the plastic on the back.

My screen is missing a piece of cross bracing, so I couldn't get it to stand up. Projected on to my usual Stewart home theater screen, the image is very, very dim. It does converge though, and all the colours work. The controls are all dirty, it needs some contact cleaner. Going to get the screen set up and see how it looks on its proper screen - the one I have is full aluminum, hopefully it reflects well, because this projector has very weak light output!

Odds are the dim pix is all 3 CRT's are weak. You can test them with
a universal adapter on a Sencore etc. The G-2 setting may be different than the usual 50V. An adapter can be made up for any checker if you have the
schematic for the checker & pin out for the CRT.
Aside from that you can check the CRT voltages. educated guessing is cathodes 125-150V ( the higher the dimmer ), G-1 0-50V, G-2 400V. For focus the
controls should focus best apx mid range. I never measured HV so have no idea. A normal chassis with a tripler gives 25-32 KV but these may run less.

If nothing else you have a piece of TV history. These were the first big screen
projo's to sell VERY well & lead to all the ones to come.

73 Zeno:smoke:
LFOD !

When we got one of these for evaluation at Zenith, we set it up in a dark room. Then someone hooked up a video camera and we played with video feedback - we made a VHS tape with video feedback set to music - kind of a high tech abstract fireplace.

I connected the B&K 466, and neither of the socket adapters which fit would test a tube, but one of them would light it.

I baked each CRT at 8.4V for 9 minutes, and 9V for one minute (timing and voltage here my best guess for what might work based on filament glow and previous experience with normal CRTs)

I turned it on and got a much brighter, washed out, green picture. Then I set grayscale, and things started coming together.

Watched an episode of that new show Letterman has on Netflix, and also tested it with video games. Had to make an adapter to use the giant video input connector, but it works well.

For the screen stand, I cut a piece of 3/4 plywood to hold the supports together, since the original cross brace was missing.

There are some subtle geometry defects which to me suggest bad capacitors, namely a bit of an wave horizontally

Convergence is great though. Need to find a manual, do a recap, and dial it in. It sits right in front of the couch, where I can play with the controls.

Glad it’s working. The curved screen has a gain to it and focuses the brightness dead center, and falls off dramatically if you sit a tiny bit off center as you probably noticed.

BEWARE. The screen will scratch if you look at it wrong. Any kind of liquid will damage the screen. I’m a bit tardy on the brochures, but I will post them.