Sylvania 1-076 arrived!

[jeyurkon]

Originally Posted by bandersen

I wonder if you could use an Eico 944 Yoke tester on it ? Supposedly they can detect a single short.

It would be interesting to try, but I think they'd give the same result. I took a quick look at the manual for the Eico. Both the Eico and the Sencore LC101 test the yoke by measuring the absorbed energy, though by different means, and are sensitive to a 1 turn short. The Sencore does it by forming a resonant tank circuit and pinging it. It then counts the number of oscillations to decay a certain fraction.

The problem is that with an iron wire core the Q is low and the energy absorbed is higher. The results I get with the Sencore are right at the border line. The Eico manual also indicates that you can run into this problem, and in that case you want to compare the reading with an identical yoke. The replacement yoke I have isn't identical, it has a powdered iron or ferrite core which gives you a higher Q.

If I remove the iron wire, then either unit should give me an unambiguous result since the Q should be quite high.

John

[jeyurkon]

I finally got around to doing more work on the cabinet. It's difficult for me since I expect everything to be square and all measurements to be a multiple of a rational number.

I replace the missing support rails and made a new base for the chassis. The square hole on the left is for the speaker cable. The oblong hole on the right is for the AM antenna wire. The small square opening is to access the adjustments that don't need frequent access. I was forbidden to touch these as a kid.

There was another hole that could only have been used to adjust the tension on the CRT strap. I don't understand why they put it there since you have to remove the chassis to remove the CRT.

Maybe they wanted to be able to re-tension the strap before shipment, after the rubber pads conformed, or perhaps make it easy for the installer to raise the base end back up if it got shaken down during shipping.

John

[ohohyodafarted]

Shit John,

If you keep doing work that looks this good, my stuff is going to start looking shabby in comparison

Bob

[jeyurkon]

I made a mount for the speaker. I suppose there's a technical name for it.

I attached a grille cloth. The proper grill cloth would have had a similar pattern, but much darker brown. Almost charcoal grey with silver thread running through it.

There seems to be a stain on the cloth. I noticed it when I went to iron it. I think it's oil or sweat. When I placed the first order for the cloth they sent me a 1'x2' piece when I ordered and paid for a 2'x2' piece. I think next time I'll order it from the place that specializes in vintage grille cloth. I suspect they put more care into it.

There's some stain, water based I hope, that I have to clean off of the finish. This was from when my dad converted the cabinet to a linen cabinet and lined it with cedar. He had to add some rails and stained them to match. There's a few holes to fill also.

I have to make some round corner molding to finish the installation of the speaker.

John

[bandersen]

Wow!! Fantastic job

How did you cut out the panel ? It looks very clean and crisp.
I'm a little surprised how red that toner turned out. I'll keep that in mind for future projects.

[jeyurkon]

Originally Posted by bandersen

Wow!! Fantastic job

How did you cut out the panel ? It looks very clean and crisp.
I'm a little surprised how red that toner turned out. I'll keep that in mind for future projects.

The round holes were drilled with Forstner bits. The large opening and the square hole were cut with a scroll saw. I then made a jig with a rectangular opening and used a laminate trimmer in a router to clean up the square hole.

I then used the router on the table saw's router table to clean up the straight sections of the CRT bezel hole. I had to touch up a couple of places on the curved sections by hand with the router.

It did come out pretty red, but the red was accentuated in the outside photo because the sun was setting on the horizon.

John

[jeyurkon]

Here are a couple of photos with it working. With just the room light the CRT shows up too bright. With a drop light it's kind of washed out. Guess I'll have to do the room light, no room light, Photoshop trick if I want a good photo.

I need to rotate the yoke a bit. Seems to have moved while carrying it out of the dungeon. I also didn't notice that I needed to center the horizontal before taking the photo. That's been fixed now.

It had good bass before mounting the speaker in the cabinet. Now it seems a bit excessive.

John

[jr_tech]

WOW! looking good! What an incredible project!

It is great to restore a set like this that is remembered from childhood, even better if the set, or in this case a major part of the set is the same one that you enjoyed as a kid.

jr

[John Folsom]

John, that set looks great. For me, the hardest thin is trying to take a good photo of an operating TV. And trying to get the exposure correct for cabinet and CRT is mostly impossible. :-)

[miniman82]

It helps if you have a camera that lets you control the aperture and shutter. I use a Pentax K200D for all my photos, but it also helps to shoot in normal room light with the brightness turned down a little.

[jeyurkon]

Originally Posted by miniman82

It helps if you have a camera that lets you control the aperture and shutter. I use a Pentax K200D for all my photos, but it also helps to shoot in normal room light with the brightness turned down a little.

Actually I have a Canon Digital Rebel and I shot the images at 1/8 sec to make sure I had full frames. I tried turning the brightness down until it was nearly invisible, but the raster was still too bright in the photo with normal room light. Maybe I should try it in the daytime in case natural light would help.

John

[miniman82]

Originally Posted by jeyurkon

Actually I have a Canon Digital Rebel and I shot the images at 1/8 sec to make sure I had full frames. I tried turning the brightness down until it was nearly invisible, but the raster was still too bright in the photo with normal room light.

Did you also stop down the aperture? I shoot in aperture priority mode almost exclusively, so I can control how much light gets in. It can also help if you use the AE lock function (if equipped), or simply meter the shot on a different object before shooting. If you meter on the screen the rest of the frame will be dark, if you meter just below the screen the brightness of the sceen will wash out the frame. You're looking for something in between.

It can help if you put the camera into auto mode, look through the viewfinder, and see what it's using for settings on and off screen. For example if it gives you 1/8 sec@f/8 on the screen and 1/2 sec@f/2.4 off screen, try manually setting it for 1/4 sec@f/4 and see what happens. Play with it, eventually you'll get it right. here's a hint: backlighting the shot helps a lot.

[ohohyodafarted]

Wonderful job John! The image quality on that set is fantastic. I would be happy if some of my sets look half that good.

BTW, I got won the Veeco calibrated leak for only $52. I hope there is still some helium in it :-) Folsom arrives on Saturday and then we start playing around to see if we can get the 925-40 to opperate.

[WA3WLJ]

Bob,
What is a " 925-40 "?
Leaks last what 10-20 years, plenty of helium in the quartz XTAL.
We send ours off once a year and they always come back within calibration.
Seems counterintuitive but, leave the valve open before and during the whole test or the value stamped on the leak won't be accurate.

[bandersen]

That picture looks excellent - very bright and clear Is that a rebuilt CRT ?

Photographing sets is a pain. The best results I've gotten have used daylight. I believe Eric photo-shopped a picture of his last restoration and it looked great.