Predicta Siesta restoration
 

This is hands down the nastiest TV I've encountered, but it was local and the price was right. I wonder how many packs of smokes it took to build up that coating ? On the bright side it seems to have preserved it well. It's a really shame about the two cracks on the safety plastic screen.


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GoJo is doing a better job that the glass cleaner.
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Steadily making progress
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I've see a lot of sets from back then and nothing this bad. I'm sure it will have an interesting odor when powered up. At least it's coming off and revealing a pretty nice cabinet.

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The original 17DRP4 CRT has been replaced with a 17BZP4 and it tests very good.
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I removed the front cover for cleaning and discovered a potential problem. There is a horizontal line burned into the face of the CRT. It must have been run for some time with a collapsed vertical. Just a thin bright horizontal line in other words. Just how visible that will be when an image is displayed remains to be seen. Worst case scenario, I do have a spare CRT, but they don't grow on trees and I'd rather not use it if I don't have to.

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Wow if that's nicotine that is really bad, no doubt this individual was a smoker and now pushes up daisies. :yes:

Wow! That is crazy. I bet it was in den where the owner often entertained large crowds of train smokers. Many of my old TV's smell like nicotine when they heat up if you smell them close up.

Good luck with the resto.

Just imagine what the inside of the owner's lungs looked like. You do good clean-up work!

Nice that they put that info where it likely wouldn't be missed!

Your cleanup job would be a lot easier if you'd throw it in a dishwasher.

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Holy Smokes! Pun intended. That was all ciggy tar? Yikes. Makes me glad I quit a long time ago. At least it is coming off.

A radio on my bench obviously lived in a house with a wood burning stove Much nicer smell than cig smoke.

Looks more like it was in the next room to a house fire that got put out...I smoke a little and I can scarsely immagine what someone would have to do to build up a tar film like that.

I agree. That makes the most sense. You just couldn't put that kind of residue on the set from cigarette/cigar smoke alone.

Yep. looks like smoke from a fire.

Bob, good luck with the restoration. Might look a lot worse once you get to the chassis. Components might be dripping with tar goo. Yuck! I never liked these sets due to the networks in them and bad air flow for heat dissipation. It will be interesting to see what the crt burn in will look like when you get a raster on the jug.

I can't wait until you post some pictures of the chassis. It'll most likely be just as nasty looking as the outside is.
This set apparently spent most of it's life high on a shelf in a Beer joint for it to accumulate that amount of nicotine staining.

I agree it doesn't seem possible from cigarettes, but it has no smoky odor - only cigarrettes. From what I can see the insides actually look ok

I've always used Scrubbing Bubbles Mega Shower Cleaner for knobs and plastic parts, aluminum I.F. can covers, whatever. It is first rate at removing nicotine and tar. It might be a little on the pricey side, but the trade off is Zero elbow grease. It might also remove some painted areas, so please test on areas that won't be visible first. I just put the parts in the laundry tub, spray liberally, both sides. Let it foam up, and completely cover the parts. Walk away and come back in 20 minutes. You will not believe the CRUD that comes off. Rinse parts in warm water and blow dry any crack and crevasses. Give it a try you will be amazed. I've also found the "lesser Scrubbing Bubbles products" ie. "pump type" don't work as well as the Mega Shower Foamer. Oh, ya, this is just my 2 cents...

https://www.walmart.com/ip/Scrubbing...unces/14862641

Bob, that is just NASTY, I can almost smell it from here. Good Luck with the set.
Tony

Restoration? More like resurrection:) You do love those challenges, don't you? Stupid thought: After you get it up & running maybe a few days with just "snow" for a raster would minimize the horiz line? Dunno.

Tony F
When I was working on a jukebox last year, I used Scrubbing Bubbles out of desperation when nothing else would remove some crud. The crud seemed to be something like tobacco residue+dust+mold. I tried window cleaner, alcohol, naptha, even Simple Green if I recall and nothing worked. It was a painted surface. The regular Scrubbing Bubbles worked like a miracle.

Good luck, but I'm guessing you will never get rid of the burn line by running a regular raster. Remember that the full raster is only 1/525 as intense as the collapsed line. You would have to run a bright raster with a dark line in the burned area, for 525 times as long as the collapsed raster ran, to even out the burn completely.

I had a set with a visible line on the screen, it was quite noticeable with the tube lit, might be less so with an actual picture instead of a blank raster.

At least the phosphor did not burn completely off...It just aged it some like how the round projection tubes from the early post-WWII projection sets that saw use have a distinct rectangle aged into them by the raster.

If Bob's lucky the difference in phosphor brightness/color could be minor enough not to notice.

Hopefully we'll know sooner than later. I intend to do a basic power supply recap and try to power it up and get a raster.

Last night I took a look inside and it's in pretty good shape.
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It's very dusty, but cleans up easily with compressed air and a damp rag.
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Here's the other end with the power supply, tuner and IF.
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A few initial findings:

The chassis was only held in by a couple screws on the tuner. Was someone working on it ? I already know the CRT was been replaced.
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* A 6FD7 was found in the 6DR7 socket and it was very loose. That's the vertical oscillator and output tube. The 6FD7 is a little beefier and should be a good sub.

I wonder if it got knocked loose and that caused the vertical to collapse ?
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* One of the caps used in the B+ voltage doubler looks like it leaked and dried out. It will definitely get replaced ASAP. The fusistor looks corroded but haven't checked for continuity yet. Was glad to see one in place and not a hunk of wire shorting it out. Hoping that is there was a problem it did it's job and protected the set.
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* Finally, the big, 4-section electrolytic can is loose but appears to be the original. There should be a clamp holding it down. Perhaps more evidence of a repair attempt.
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I spoke too soon - the fusistor has been compromised :sigh:
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At least the cleaning is progressing nicely.
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I found that Spray 9 does an excellent job. It is a harsh cleaner though so use with care.
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I think an auto finish detailing product like something from Meguires will even out the color.
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Now back to the chassis...

I'll bet you can remove and replace the PCB with all the wire-wraps from memory by now.

Some of the 17" predictas actually have enough holes under the main board to get a soldering iron in without pulling the board...I did that on mine.

Good luck. Mine is completely covered in black soot from the house fire. It looks nothing like the crud you are cleaning off that set.

I've been tackling this set over the past few weeks. Here it is up on the workbench for a closer look. Despite the filth, it's all there and appears to be in pretty good condition.

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Rather that take my usual shotgun approach, I decided to have a little fun and see how far I could get without removing any circuit boards.

First, the power supply. Although it has a power transformer, it has a voltage double for the B+. I could see the main filter caps were leaking and crusty so they had to go before attempting a power up.
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Here they are along with some new diodes installed on the existing terminal strip. Also did a little vacuuming and pulled the HV cover off.
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I traced out the wiring for the remaining electolytic caps and strategical located them where I could. Also discovered a fried resistor and replaced it.

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Ready for a power up attempt.
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No smoke, but also no vertical deflection. The replacement CRT in this set tests like new but has a badly burned line into it. I suspect it's been run for some time like this.
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It took me a better part of a day to find the problem. Would have taken a lot less if I had immediately done a resistance check on the vertical tube pins can compared to Sams.

Instead I had puttered around with swapping tubes and replacing parts in the vertical circuit.

The real problem was an open vertical linearity control. That's a wirewound control riveted to the back of the chassis and apparently a common failure point.

I tacked in a 560 ohm resistor while I track down a replacement.
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Yay, a raster!
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and with a better signal source, a stable image. No sound though.
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Something else I battled with was a damped tube that wouldn't stay lit. I had to keep applying pressure on the side of the tube. I assumed it was a bad socket or broken PCB trace.

Here's my quick fix. I soldered a wire directly to the filament pin that wasn't making good contact.

Again, a little closer observation and better troubleshooting would have found the real problem sooner.

I was a broken PCB grounding stake nearby. All of the tube filament have one side grounded and this broken one supplies the damper tube and not much else. My applying pressur to the tube was really flex the PCB for the stake would make contact.
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Then, on to doing some cleaning. I'd heard good things about Simple Green and that getting vintage electronics wet wasn't going to do any harm so here we go...

First, the tuner.
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Ok, I'm impressed!
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Next, the HV box
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Followed by the main board which I had removed by now. I got as far as I could without pulling the board.
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That just left the main chassis.
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That's better.
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Also the yoke wiring was disintegrating so I rewired it using super flexible silcone insulated wiring. The original horizontal yoke wires had thinker insulation so I assumed they needed something in the 1-3 kV range. After searching around, I went with test lead wire.
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Unfortunately, shortly after reassembly I was having screen fade issues. I could smell something getting hot and assumed I had made a wiring mistake. While trouble shooting the circuit breaker in my PR57 popped. Finally noticed it was the power transformer that was roasting! Something shorted out inside. I tried to get water out when I washed down the chassis and baked it in the oven for a while. So who knows? Might have been moister. Might have just been its time. Luckily, I had a spare handy.

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Back in business. Have sound now too after tweaking the coils a bit.
Shame about the very visible burn line.
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Nice job I would think it was used in a bar/pub I have seen things covered in tar like this from drinking establishments. The screen burn is a shame but wouldn’t put me off it .