Random Light Bulb inside Sylvania Superset?
 

A friend has found a 1983 model Sylvania Superset console television inside a basement and I'm trying to help him out with it. I had him take the back panel off for inspection before trying to plug it in, and inside, on the bottom of the case, he found an incandescent light bulb in a socket that is alligator clipped into the circuit somewhere. I have no idea what someone was doing here, but my gut feeling is either some sort of 'dim bulb' tester, or otherwise an improvised resistor for a kind of 'band-aid' fix. I have attached a photo of where the alligator leads are clipped on; this is all he has at the moment, but I will try to get some more. I tried to upload more images but can't resize to VK's liking from my phone. I have never encountered something like this inside a TV!

That is weird. Guess what I would do is trace down the start and end point of the connections in relation to what they're "supposed" to be doing or subbing for and go from there. It might be a "ballast" of sorts for a something they didn't know how to repair properly or possibly feeding a little more voltage to something they think is running low. Hard to say but either way it's going to need some detective work.

So from your username I take it you're a Yamaha motorcycle fan? 1981 SECA 750 on my end.

Your thoughts seem to align with my own. On the Yamaha front, I like most of their stuff but my username comes from their stereo gear! My first system, which I inherited from my parents, was an early starting point over on the sister site, AudioKarma.

Seems to be at the AC input. I would guess for current control
( dim bulb) while trouble shooting.
Zeno:smoke:

Guess the next important question would be how large the light bulb was in the first place? A superset would take something on the order of 100 to 150 watts running and double that power-on surge, this might give a clue as to it's intended function.

As for Yamaha Natural Sound, I had a hand-me-down A-450 in high school and repaired a lot of the later Yamaha p2050, p2100 and p2200 pro amps over the years. There was an R-50 in the mix but it was stolen. I joined audiokarma in 2006 but was inactive during the split, it's been a few years.

Could it be a "There I fixed it" replacement attempt for a thermistor at the power input?

Lol. What a "fix". My guess is a power resistor. If it is, now the real question is what caused it to fail?
There's probably a shorted cap or something fried ahead of it...

If this is the chassis I think the FBT shorts, blows HOT & pass transistor.
The OEM parts net us near $100 USD. When done most of the CTR's
were soft as a grape. But when new they gave an awesome pix
for a few yrs.

Zeno:smoke:

I am unable to upload images because the site doesn't like them but the light bulb appears to be bridging a fuse socket labeled FS500, in the power supply...the main AC line fuse? This seems dangerous...times like these I wish the previous "technician" had left work notes behind!

Upload your pics to an external host & embed them here... I used imgbb to serve a lot of photos for my earlier threads on this board but my favorite service so far is catbox.moe

I had used various hosting sites in the past but grew weary of the images inevitably being deleted and links no longer working...perhaps I just need to find a more reliable site.

imgur seems to be sticking around for the long haul

The light bulb is a 100-watt. Here is a photo of the alligator clips attached to the fuse terminals. EDIT: Required fuse is a 3.2 amp slo-blow type. I think the first course of action would be to see what happens if he puts the proper fuse in the holder.

https://imgur.com/a/zenith-tv-with-c...holder-q2HPvp5

Flicker has had my stuff up since Photobucket fell apart a decade ago... Despite the 1000 free images hosting limit (if you have multiple email accounts you can get around that by opening another flickr account...Or deleting some stuff once you hit 1000) and flickr provides BB code so you can make your picture appear in posts you add it to....as opposed to Imgur which only gives it's users links (I hate it when people post URLs I have to click to see). If I have to click a link to see a picture I often won't and instead scroll past.

My apologies that my photos are too much effort to view. I've never heard of someone complaining about tapping one time to view an image, that sounds like an incredibly first world problem from my perspective.

You can also imbed with an Imgur photo, but you need to get the link to the photo and not the Imgur page.

This can be easily done by opening up the photo in Imgur and then RIGHT clicking on the photo and selecting "Open image in new tab" in most browsers.

That will open up the permalink of the photo in another browser tab.

Then you click the little photo icon here:

https://i.imgur.com/FpVyLrv.png

And then you can just paste in the permalink and the forum software will automatically embed the image. No sweat.

For example, your alligator clips photo is this permalink:

https://i.imgur.com/vPLole0.jpeg

Another issue I have with embedded images (as is apparent here) is they often stretch past the dimensions of the rest of the page, distorting the layout/formatting.

Sorry to go so far off-topic, though.

That's really a feature of this ancient forum software that VideoKarma still uses more than anything else.

Any recent forum package will resize an embedded image and format it within the text blocks.

I sometimes go to the trouble of resizing images multiple times in order to make a photo look good on a BB style forum like this one, but not always.

Regardless, it's still nicer for the whole flow of a thread for the images to be present with the rest of the text, and it makes it far more likely that people will respond. For reasons I shouldn't have to mention, people in general are loathe to click on random links.

I guess I don't consider links to the more well-known hosting sites (i.e. Imgur) to be random. I've never had issues sharing images before, so I am genuinely taken aback by the considerable aversion to tapping a single link to view a relevant image. It was the easiest way for me to share from my cell phone and I didn't think it would cause animosity to such a degree.

I would get back on topic, but I have no updates to share as of now.

Flicker lets you choose the resolution of the BB code image you get from them (regardless of the native size you uploaded) and you can post it in several sizes simultaneously. I find selecting 800x600 never disturbs forum width formatting, but they let you go bigger and smaller too. Smaller is great for when I make a for sale topic (my bianual ETF swapmeet threads are an example) or something I'm posting on has a lot of photos as I can get them small enough that 2-3 fit side by side without disturbing formatting.

I do almost all forum reading on my phone now (stealing a few minutes here and there) and cellular Internet here is often glacial speed trash....If someone posts a lot of links it can burn several minutes waiting for the link to load, videokarma to reload, the next link to load and so on.... It wastes enough time that doing it usually isn't worth the effort. But if they are embedded they often all load into the post while I'm reading down to it thus I'm not waiting for page loads.

UPDATE: I had him put the requisite 3 amp slo-blo fuse in the holder and plug it in...the set clicks once when power button is pressed, but nothing else. He says he might have felt static on the front of the tube. No weird sounds or smells, fuse intact. He wants to give up on it (not very electronics savvy) but is there a chance this is something simple or stupid? Multiple power button presses results in the same single click. Perhaps weak cap in power supply?

Zeno mentioned that this particular set tends to have a shorted flyback, and that get real soft when fixed, so it might be a lost cause.

However, if it was me, I'd probably check the all the voltages first, and I'd certainly measure any big filter cans.

You will probably need a schematic to get anywhere with it unless you stumble upon it.

I did make note of that, though I wasn't sure what was meant by 'getting soft'. The set at least has circuit diagrams inside the cabinet.

Yeah, that's like meaning the opposite of "sharp" when referring to the raster. Also can be more technically referred to in specific ways, depending on exactly how the raster looks "soft" such as "bloom" or "smearing." Not to be confused with screen "artifacts" like "ghosting" or some kind of pattern.

I would highly recommend just for starters to read the whole repairfaq of TV information. It's not going to cover everything, but it's a good start on really understanding different modes of failure and such

https://www.repairfaq.org/samnew/tvfaq.htm

A few easy things to try.
1) remove the modules & clean the contact. Check for cold joints also.
2) Look on the tuning ASSY for the standby transformer & on/off relay.
They got cold joints.
3) Post the layout chart & pics of chassis and tuner assy's

Soft tube is a low emission / weak CRT that still give a pix, but a poor one.
its usually a slow prosses that over time gets worse & worse.........

Zeno