Got the Sylvania! - Videokarma.org TV - Video

veg-o-matic · #1 07-31-2005, 09:20 PM

Picked up the Sylvania yesterday, but didn't get it into the house until this afternoon. Nephew was helping and I noticed all 6 knobs at the bottom had fallen off at the same time. When I opened 'er up, I found out why--the chassis was bumping around inside the cabinet! I think one more good jolt and the picture tube would have been a goner.
The picture tube, by the way, must have been replaced at some point because it's an RCA Perma-Chrome Hi Lite.
The chassis is DO211, which makes the model number 25LC105, according to the SAMS.
This set has some weirdass tube sockets. They're more like just a bunch of little connectors on the PCB rather than regular Bakelite sockets. There are some regular sockets, too.
Okay, so I fired her up and the pictures tell the story. The picture actually looks focused to me, if smallish and green. The pic looks B/W, but it's really green. The first time I turned it on, the picture was more orange. The color and tint knobs don't seem to do a dang thing. I had to fiddle with the HHold knob a little to get a picture.
In poking around a little, I noticed that some of the tubes in the weird sockets were loose. This may be what the service guy meant when he said the sockets were worn out. Is there a good way to tighten these up?
Other problems are that the channel numbers don't move in the window, it needs a light for the UHF tuner, a brace inside neets to be reattached, and there's about 40 years worth of dust I have to vacuum out.
Once I get it cleaned up, I was thinking of messing with the height control to see what that does, if anything. It also looks like I'll need to straighten out the yoke, but it might be just my eyes.
Any ideas what to do next? Is the single-colorness going to be a problem? It actually looks like my Heathkit does, but then the blue gun kicks in and I get full color. Haven't had this set on long enough to see if there's any change once it gets good and warmed-up.
Forward!
veg

bgadow · #2 07-31-2005, 10:09 PM

The focus looks okay from here. I'd say by "won't focus" maybe they really meant it just wouldn't tune in clear. I'll wait until you've done more tube-jiggling & preliminary work before making any guesses.

andy · #3 07-31-2005, 11:00 PM

Focus can mean anything from fine tuning to convergence to 'regular' people.

Chad Hauris · #4 08-01-2005, 06:53 AM

The tube sockets that look weird are where all of the plastic has worn away due to heat...for a reliable connection you need to replace the socket using a new good socket with bus wire soldered to each pin to run back to a good point on each trace (the board may be burned right at the connection point the socket).

You can see in the picture of the chassis that one of the tubes is crooked...you won't get a reliable connection with the worn out sockets.

veg-o-matic · #5 08-02-2005, 08:29 AM

Okay, I spent some time last night cleaning and adjusting and stuff, and here's what I came up with (sorry no pics yet. With luck, I'll be able to take one tonight):

Got a nice, clear, well-focused green picture after twiddling the fine tuning. Messed with the height, v. centering and v. linearity controls and have a picture that fills the screen. People's heads seem to be the right shape

so I guess I got the linearity right. Straightened up the yoke, but I don't think I tightened it up again as it's a little off. Or maybe I'm a little off.

Did the gray scale adjustment in hopes of restoring some color. I got nice bright green and blue lines but no red, no matter which bias setting I used. Cleaned the drive controls for good measure but no change. Set had been on for maybe 30 minutes at this point. Snapped it out of service mode and was presented with a really nice BW picture!

This lack-of-red thing has me concerned. If there were really NO red, wouldn't the picture have a blue or green cast to it? It's really nice black and white. The convergence is off at the edges (natch) and I can definitely see some red up there. Does that mean anything? Should I test the tube and maybe give it one of those jolts that "restore" it? Anyone got a tube tester I can borrow?

The color and tint controls still have no effect on the picture, so I'm guessing they're involved in this somehow.

Color or no, I'm really pleased at how much progress has been made with just some minor tweaking. Picture to come!

veg

Chad Hauris · #6 08-02-2005, 11:47 AM

The drive controls adjust the amount of the video signal coming from the B&W video output tube to each of the cathodes. These are not adjusted during the service line procedure as there is no video signal at the cathodes at that time.

When you set the switch to service you adjust the SCREEN controls for just-visible equally balanced red green and blue lines. Careful...there can be 1000 volts at the screen controls.

veg-o-matic · #7 08-02-2005, 12:18 PM

Thanks for the heads up about those 1000 volts. I had no idea!

You're absolutely right--it was the SCREEN controls I used for the grayscale setup. Still didn't get any red though. Tweaked up the blue and green drive knobs to get a nice BW pic with no color in it.

One of these days I'll get the terminology down. In the meantime, can't I just call everything the Frammis Meter and the Gronkulator?

veg

holmesuser01 · #8 08-02-2005, 02:59 PM

Check the tubes that are marked R-Y, B-Y, and G-Y. If the Red Y is out, this can cause your problems. Most sets had all 3 functions in one tube, Magnavox did, fer sure. My RCA's have 2 6CG7's that do all 3 and a cutoff function.

Best of luck. Dont give up on it. You should find your problem pretty fast.

Be sure to check the Glonkkulation supressor and the Horizontal Disconsimulator. Sylvania invented that one!

veg-o-matic · #9 08-02-2005, 03:23 PM

The Glonkkulation supressor! Man, I completely forgot about that!

I'll drag out my cross-channel supressor compressor tonight and check it out.

veg-o-matic · #10 08-02-2005, 09:10 PM

Got out the ol' camera and fired up the set tonight so I could show the progress. I read something about maybe the color killer being misadjusted so I went around and twiddled with it, but didn't seem to do diddly.
Then, as I had heard others do, I started tapping tubes. Okay, now that made some difference! There's some color now, but not in the right places at the right time. I'm going to take a stab and guess that the color sync is out of whack?
Anyway, enjoy the pix!

veg

Bill R · #11 08-02-2005, 09:26 PM

Replace those bad tube sockets and that may go a long way to getting the color back in sync. Also check for bad solder joints on the circuit board.
Good Luck,
Bill R

polaraman · #12 08-02-2005, 11:28 PM

Veg, Can I have it after it is fixed?

polaraman

veg-o-matic · #13 08-03-2005, 08:10 AM

Quote:

Originally Posted by polaraman

Veg, Can I have it after it is fixed?

polaraman

Nope. You turned this down once already. "The time to take the hotcakes is when they're passed!"

veg, who's kind of amazed, actually

veg-o-matic · #14 08-03-2005, 01:13 PM

I did a little online shopping for replacement tube sockets. Since the original ones were apparently burned to a crisp, I guess the new ones should be ceramic? Or does it really matter?
I also came across something called a "socket saver". What is this, and do I need one? It was about 8 bucks, as compared to like a buck and change for the sockets themselves.

blue_lateral · #15 08-03-2005, 01:43 PM

I think any sockets that would solder to your pc board will be plastic like the originals probably were.

Are your circuit boards burned/crumbling too or are only the sockets bad?

John