Little white Sears 9" SS color set

[AiboPet]

Sorry....posting this from work, so don't have the actual model handy.

Bought a little 9" solid state set from ebay. It's likely from the late 70s....white cabinet (plastic of course) and pretty generic looking. Powers right up and has an okay picture with just some very mild convergence to clean up. This is actually the BIGGEST set in my collection since I collect "micro" TV sets. I got this thing for REAL cheap though (like ten bucks...was like 15 to ship it).

I'll post some pics later

It has an odd problem though, and have pulled a part off the CRT board that puzzled me...which I will also post a pic of later.

The set came up fine (I did use a Variac, even for a SS set..just to be safe) but almost IMMEDIATELY there was arching....and I could see it when looking down through the back of the set. I could pretty much see it was either coming from the CRT socket or the board itself back there. I took the back off and brought the set up again and was immediately greeted by this same arching, but I could SEE it this time.

On either side of the CRT board, are what look like VERY large ceramic disk capacitors (about the size of a quarter). The weird thing about these though, is they look to be purposely "open" at the bottom. You see the regular beige ceramic coating around the top 3/4 of the disk...but the last 1/4 or so is "bare" and you can see part of a silver metallic component inside it. I thought something was "wrong" with this part...but the same part appears to be on both sides of the CRT board.

The arching.....is coming from one of those. At first it was "from that piece to ground", but it stopped when I bent the component over to be further from the PC board (I widened the air gap to ground by twisting this part to not stand straight up). I then noticed I could watch the set WITHOUT the snapping.....but I would still get a snap about once every ten minutes or so. It still comes from this one component.

Now the dumb part.

I decided to REMOVE the little ceramic disk. First, to get a better look at what it was....and to see if the set was at all affected by it missing.

The set comes on just FINE without it, and didn't seem to change anything. it ALSO didn't change the "occasional snap" about every ten minutes to ground.

I will post a pic of the little part later...but suspect most of you have seen one before. My guess is it is a ceramic capacitor, but I never seen that weird "naked on bottom" part.

I will look later to see if the focus pin on the socket looks okay...since all I can think of that would arch like 1/4" to ground would be focus? I'm also gonna take a good look to see the shield around the CRT is properly grounded. I was thinking maybe the HV is building up around it and somehow discharging through the neck board...if it isn't the focus doing this. Can I safely run the set without the HV connected to the CRT so I can see if it's still snapping?

As I mentioned earlier...aside from some touching up to be done with convergence I can see, the set sounds, tunes...and has a decent little 9" color picture. I did notice that when I would hear this snap, the picture would go white for like a quarter second.

I do not have a CRT checker (yet), but I don't SEE anything in the picture that would indicate any problem with it's CRT. The set really looks to have had a VERY easy life. It was little more than just dusty inside.

[Eric H]

Those are "Spark Gaps" they are designed to arc, I'm not sure what the purpose of them is, maybe someone else knows that part.

[AiboPet]

I'm pretty sure they may be designed to spark INSIDE of them then if that is what they are. I kept seeing a 1/4" spark jump from one side of the one to a ground trace on the neck board. I'll hafta check if one side of that part I took out IS connected to ground....or if one side of the one that is still there is (on the other side of the neck board). Maybe for some reason I'm getting a big charge on one side and it's arching from that side to ground instead of through the part where it wouldn't be a big loud "snap".

[zenithfan1]

They protect sensitive electronics from voltage surges, supposedly. I think the one in your set is bad, hence the spark jumping to other things. There may be a bad cap or something causing fluctuations in voltage, I've never seen one spark in a tv set. check for any breakdown of insulation for the HV section, once you have an arc, usually a carbon track will form making a conductive path to whatever is being arced to, like a nearby ground. In your case something on the neck board. After re-reading your post, you may be right about the CRT grounding. It looks like a charge is building up and going to whatever ground is closest.

[AiboPet]

Cool... I'm still at work, so at least now I sorta have an idea what I'm looking at might be going on with this cute little set. I did try and do a Google image search on "Spark gap"...and really only got the sort of things you would expect to find. There was no weird quarter sized "partly naked" beige ceramic cap looking item....so I'll still hafta maybe post a pic of the one I pulled out later.

If I get to the house and pull the back off that thing again and see one side of that little part is ground, then it most likely IS a "safe path" to discharge something, which NOW I have robbed that circuit of. Removing it made ZERO difference in the picture, but I did still get the arching snap about once or twice every ten minutes or so.

I like this little set. it's very "plain" 70's....and I'd like to actually find a place for it where I'd actually watch it, AWAY from my usual little quirky collection.

[Sandy G]

If this is the li'l guy that is kinda roundish-Vaguely shaped like a '70s toadstool, I have one, too, & was VERY pleasantly surprised by the pretty darn good picture it makes...I THINK they were made by Toshiba. And-N'yah, N'yah- IIRC, I gave the munificent sum of 1 Dollah-Plus shipping, of course- for mine offa Epay several years ago... Wasn't expecting very much, so I was MOST happy w/it...Sometimes, you just get lucky like that.

[Eric H]

I neglected to mention that I think they are only supposed to arc if something is wrong.

Perhaps as suggested it's just dirty or tracked.

Blowing it out with some air might help. or maybe hosing off the board with some no residue electronics cleaner.

[zenithfan1]

Originally Posted by Sandy G

I THINK they were made by Toshiba.

Yes, Most if not all of the sets for Sears were made by Toshiba in the '70s.

[AiboPet]

Pictures....

First is the picture I have, even with this little part out.

Second pic is of the one I didn't take out..does not arc.

Third is the part I took out. It's on the other side of the neck board. This is labeled as "C902" on the board and does have the symbol for a capacitor silkscreened on there.

Fourth is a pic of the neck board, you can see that this SAME little part (is labeled as a capacitor on the board) is on the right. This one I did not take out, and it doesn't do this arcing thing at all.

I looked carefully at the board and see no burn marks at ALL anywhere....and no part APPEARS to be under stress and the board is bright and clean on it's green side with all bright solder and traces. I also did pull off the board from the CRT and see nothing that indicates any corrosion or breakdown of the focus pin (I'm gonna assume this is the seperate lone pin at the top seperated by some space from the others)

I've run the set at least a couple hours now and have NOT heard a single snap...or seen anything go weird. I'm starting to think I may have "fixed" something by removing and replacing that neck board on the CRT. I had not touched it since the set was shipped, so who knows...coulda been unhappy in some way.

[AiboPet]

Okay....Dunno why really, but decided to just put this capacitor BACK where it was after a couple hours of not getting the fireworks.

Soldered it back on the little stubs I had from SNIPPING the thing out a couple days ago (I know...shoulda removed it by desoldering it).

NOW.....comes on and plays, and turned it off and on several times without seeing or hearing a single snap. Also, as I noticed before, this cap appears to have NO effect whatsoever on the picture whether it is there or not.

I did have a go allover with just some canned air...because it was simply dusty in some places, but at this point, looks like this little set may not be in any trouble after all :-)

I have no CRT checker yet, but would have loved to practice checking the CRT on this little set. The picture is surprisingly good for what looks to just be a very plain 70's color portable set. Not a single scanline...and I can set it up to get a REAL nice B/W picture. I remember my TV shop teacher saying that a color TV in real good health will be able to produce a very good B/W picture.

[Eric H]

That doesn't look like what I thought it was, looks like a Cap.

I wonder if it was just dirty, or maybe had some Tin Whiskers where the metal is exposed?

The picture you took of the second one shows it to be quite fuzzy with dust and whatnot.

[AiboPet]

Yup....was just a little fuzzy with whatever dust was on it. A quick blast of the canned air cleaned off quite a bit of REAL fine dust....hit that whole neck board with a real soft worn out toothbrush but didn't get much more after the little shot of air.

Probly this weekend I'll get around to dusting the remainder of the set. Not really much else to do with it. I may look into what appears to be a REALLY minor geometry problem. I notice when watching HD content from the cable box (letterbox), I notice the center JUST a tad narrower. I think I may remember this as "pincushion", but it's a very slight case. I don't see this at all with a fullscreen picture, even if I play with vertical size. I'll put a crosshatch on it sometime over the weekend and see if maybe the set just hates that letterbox picture from the cable box.

The little part of course DOES look like any ceramic cap I've ever seen...EXCEPT I just don't recall ever seeing one that looks "naked" on the bottom like that. BOTH of them on the neck board do look exactly the same though. Also, since I've started molesting the set and cleaning what little dust...messing with the CRT socket/board connection, it's not at all given me that problem. I've even put the cap back that I removed...and still not.

[holmesuser01]

Originally Posted by zenithfan1

Yes, Most if not all of the sets for Sears were made by Toshiba in the '70s.

Sanyo built alot of portables for them, too. I worked there back then.

The good thing about working for Sears Service was the wealth of information they would supply to the techs on each of these TV models.

Most of the sets would have the same problems... Generally well-built chassis.

I have a Toshiba-built Sears solid state 17" color set with a brand new CRT with a lovely picture. The red phosphors in the CRT are very deep red.




Back to the topic: Not able to see this set, but the sets produced back then did have spark gap capacitors. Moisture often ruined them. Get the model number off of it. XXX.XXXXXXX The first 3 numbers is the manufacturer.

[zenithfan1]

Oh yeah, thanks, I forgot about the Sanyo built sets. Duh, I used to own one too. LOL!

[John Adams]

The 562 at the start of the model number designates the manufacturer.
562=Toshiba
http://www.applianceaid.com/sears-ma...ring-codes.php for long list.