This is on my sylvania SS set

everynow and then I will get a loud snap sound, enough to startle you, and the the pic gets a bluesh tint, that quickly fades away and is back to normal, maybe 30 seconds tops.

Of course I can look for it with the back off for hours and nothing will happen, then I will look away for a min and "snap"...

any ideas on what may be going on?

Hmmm, check the CRT for shorts in the blue gun. Also meter the drives to the CRT pins. Also could be anode arc. That would explain the loud snap. I think that can mess with drive voltage as well. Discharge the CRT and clean the aquadag and anode cap and see if it still does it.

the HV lead off the anode button has a plastic stand off, but further down the lead it come directly into contact with the metal CRT shield, and it looks a bit blackish right there. I am going to wipe that off, and get a closer look at it. Will also make up a little card board stand off to get that away from the metal shield.

there was a large amount of dust all around the rubber anode boot as well.
seems like a red substance is sealing it to the crt.


Question about a CRT short making the snap, would not an internal arc be silent, inside the high vacuum of the CRT?

I had a SS 1970's Philco that would make a loud snap now and then, it would ruin the CRT in a month or two.

Turned out to be a bad CRT socket arcing over from the Focus pin, essentially "rejuvenating" the tube over and over until the cathode was stripped.

that has the dumb socket built into a pcb, I will get out the magnifing glass and check it over.

Ok I could see the focus lead coming out of the socket, and going right by a resistor lead on that pcb.

I dressed it up and away from the board as soon as it exits the socket. watched it for about 30min, no snap.

I will be checking the crt in a bit and see how well it tracks.

Iguess it would not hurt to clean that up real well and maybe put a dolup of silcone right around that lead where it exits, that would also help maintain the lead dress.

IIRC the one time I was close to it, it did seem the sound came from around CRT socket/pcb..

I did not see it but "think" that was the area.

I sure dont want to see my nice sylvania black matrix tube ruined. I did notice the grayscale was a bit bluer than it should have been when a B&W show came on.

In color TV's of this era, arcing and/or snapping usually comes from one of three sources: The CRT anode, a cracked HV tripler, or the CRT socket. From what yours is doing, I'd say it's the socket. You may can take it apart and clean it; but, I'd probably replace it just to be on the safe side.

its an odd ball the pc mount. I will have to look thru my stash.

I guess it would not hurt if I were to use a regular socket and just cut the wires short that go to the pcb.

turned it on, 15sec later "snap" of course thinking I had it fixed I was not watching the back. So it will be left off now until I replace that socket.

searching on line for sockets, everything is coming up from china... 1.50 for socket 25 for shipping...


anyway, I was looking at the schematic, there is a built in spark gap at the cathodes says "spark gap part of CRT socket"

now I am concerned, I not only have to locate a CRT socket, but have to find one with a built in spark gap, and on top of that there is no part number in the sams.

could not find on in my stash, decided to try one more thing, some concetrated blast of mass air flow cleaner into the socket pins.

will report back later...

we had that issue back then.you can take a socket from anything and wire it in.did more than a few like that.a little ackward getting the back on it,but it works and makes it really easy to service.they seem to arc on that focus pin.also,there should be a plastic grommet that holds the anode.mounted on the degaussing shield.what ever you do,dont let that ruin your crt!

we had that issue back then.you can take a socket from anything and wire it in.did more than a few like that.a little ackward getting the back on it,but it works and makes it really easy to service.they seem to arc on that focus pin.also,there should be a plastic grommet that holds the anode.mounted on the degaussing shield.what ever you do,dont let that ruin your crt!

did you just remove the old socket and wire the replacement to the pcb? what about this "spark gap" that was "part of the socket"..

I will have to continue my hunt for a socket, I have an old color brightener that I could sacrifice. I dont like the idea of a brighener anyway.

Yeah; but, I don't know if that brightener socket has a built in spark gap.

that's the deal, I dont know how that spark gap is supposed to work.

I am thinking of removing the socket and seeing if I can do some surgery to open it up. It looks like it has 3 plastic pins that have been melted over.

If I drill them out and open the socket maybe I can see what the issue is. I have plenty of micro plastic screws to put it back together again.

sorry.socket must have a spark gap.zeniths are the best.philco s are good too.

pic of the PCB/socket, note brown gunk.

I've got ~ 18 color CRT sockets plus 3 brighteners. Anyone wants them, free + shipping.

update, since cleaning the socket, there have been no snaps. Not saying it's fixed, only time will tell on that, BUT now I have a new issue.

Vert shakes. starts up fine, but after a few min vert gets a bit jumpy, not enough to break sync, but enough to be annoying.

figure I will start with some cleaing of vert pots, reset IC and transisitors. if that does not do it I will hit it with some cool spray on suspect parts.

Next will be to monitor the B+ around the vert section.

I only recapped the electros that tested bad. maybe I am going to pay for that now.

pull the 3rd board.the horizontal/vertical module.look for solder breaks around the yoke and convergence plugs.extremely common on those set.vertical will jump and shake.drive you insane.solder those good.those sets were not known to have have any vertical issues other than joints.make sure you put the screws back in or you will get a nice set of lines on the left side of your set.good luck!