1960s Sylvania Color TV: My first all tube color TV

[vortalexfan]

Originally Posted by old_tv_nut

I haven't heard of problems caused by tipping a picture tube forward. Camera tubes, yes, but not picture tubes.

That's interesting because I've worked on several old portable color TVs from the 1980s and and even a few non-portable units from the 1980s that when I tipped the TV forward (or maybe it was on its side) the picture tube would get messed up by looking like someone ran a powerful magnet across the screen and that would be the end of the TV.

Any ideas as to what I was experiencing and what would be the best way to avoid that?

[dieseljeep]

Originally Posted by vortalexfan

That's interesting because I've worked on several old portable color TVs from the 1980s and and even a few non-portable units from the 1980s that when I tipped the TV forward (or maybe it was on its side) the picture tube would get messed up by looking like someone ran a powerful magnet across the screen and that would be the end of the TV.

Any ideas as to what I was experiencing and what would be the best way to avoid that?

You have to use a degaussing coil. I also used a tape demagnetizer.

[zeno]

Several ways to handle chassis

GOOD
Remove legs if it has them. they either unscrew or twist off. Put the
set on its side & remove all but one rear chassis bolt. The chassis will swing out to work on.

BETTER
Same idea. Put TV on bench upright with a few feet behind it. Find a box
about the same HGT, pull chassis & flip out onto box.

BEST
A test jig but you dont have one !

BTW the purity will be way off while on its side running. Also just
be sure you dont pull wires too tight. Take it slow.

73 Zeno
LFOD !

[old_tv_nut]

Originally Posted by vortalexfan

That's interesting because I've worked on several old portable color TVs from the 1980s and and even a few non-portable units from the 1980s that when I tipped the TV forward (or maybe it was on its side) the picture tube would get messed up by looking like someone ran a powerful magnet across the screen and that would be the end of the TV.

Any ideas as to what I was experiencing and what would be the best way to avoid that?

This sounds like the shadow mask was previously broken loose and got permanently dislodged when you tilted it.

[vortalexfan]

Originally Posted by old_tv_nut

This sounds like the shadow mask was previously broken loose and got permanently dislodged when you tilted it.

OK thanks for letting me know.

[vortalexfan]

UPDATE: I finally got around to removing the chassis from the cabinet and I tested the electrolytic caps and they all tested good yet according to my ESR Meter, and that would make sense seeing as the TV still had full screen deflection.

I also poked around and tested a few of the resistors on the various boards in the TV and the resistors for the most part tested within specs yet, those two 68k Ohm 2W resistors were the only resistors that measured out of tolerance and so I put in an order for some over at Digikey (because Mouser didn't have any 68k Ohm 2W Resistors in stock unfortunately) also the two 68k Ohm 2W resistors were the main resistors you guys said would give me the most trouble.

I also was able to clean the pots and the switches better with the chassis out of the cabinet.

[vortalexfan]

UPDATE: I finally got those two 68K Ohm 2W Resistors replaced.

But I have a question about a couple of capacitors I saw in the chassis that look like they might be paper caps but I'm not sure because there were film caps that looked like these types of caps as well, and plus it seems a little odd that they would of been using paper caps in the late 1960s when Mylar/Film caps were the predominate type of capacitor in use by that period in time.

See pictures below.

[vortalexfan]

OK, so I've pretty much replaced every single tube in the TV except the Vertical Output/Vertical Oscillator Tube which is a 6LU8 tube which I unfortunately do not have in my stash, and the Color Output Tube which is a 6MD8 tube, both of which are compactron tubes and both of which I do not have access to in my tube stash; this is odd because all of the other tubes in this TV I had at least one or more of in my tube stash, and most of them were Sylvania branded tubes ironically enough.

Unfortunately all I'm able to get the TV to do right now is to do a barber pole effect when I have the color turned on, and the vertical isn't locking in at the right frequency, its running at half frequency right now (where the picture is showing a bar in the middle and the top half of the screen shows up at the bottom and the bottom half shows up at the top half of the screen.)

I've tried adjusting the height and linearity controls on the back and it doesn't seem to help much (which is why I'm thinking the Vertical output and oscillator tube is either weak or bad.)

I'm guessing that the barber pole effect (the color not locking in) is either due to a bad color output tube, a bad 3.58 MHz Crystal, or the color demod transistors are bad.