Thanks for the compliment and the link. The axial ceramic cap color code table is close. But, like all of the others I've looked at they don't include silver in the multiplier. I guess I should just assume it follows form since that gives the schematic value.

John

Horizontal progress
 

I think I've found the problem with the horizontal circuit. The symptom is that it's only stable with the blanking bar down the center of the screen.

I don't fully understand the circuit. It's a sine wave type horizontal AFC.

But suffice it to say that the output of the sync clipper is fed to the horizontal discriminator through a 100pF capacitor. It was supposed to be an axial ceramic. It's actually a Micamold.

All the bad things I've heard about micamolds are justified. If a capacitor can be evil, this one is. The discriminator circuit requires it to not have any leakage. It has about 16 uA at rated voltage. But it gets weirder. The capacitor testing gives up trying to measure the value if the cap's been resting for a long time. After measuring the leakage, the capacitance tests out at 300 pF. It then gradually ramps up to 3,000 pF after a few minutes of testing.

At least this one is easy to get to. The other one that I'll replace is used to turn the line cord into an FM antenna. Given that it would probably burn my house down I'm inclined to replace it.

I wish the 13 others weren't so difficult to get to; I'd love to replace them but since they seem to be working I guess I'll replace them when their time comes.

John

Horizontal Fixed
 

Finally! :banana:

I changed the micamold and found two caps I had switched. A 0.005 and a 0.010 uF. There's one micamold left that is for the horizontal ringing coil. It's hard to get to, but I should change it.

Here are some photos. Is this the typical linearity that you should expect for a set of this vintage?

John

John, those photos represent outstanding work on your part. Congratulations on getting that old babe back to as good as, or even better than, new.

As to linearity, looks to me like you're down to the point where any deviation may only be in the eye of the beholder.

Three cheers for a job well done! And thanks for sharing all the details with us.

Roger

Awesome!
-Tony

While doing some fine tuning of the set I realized that the Zenith Wavemagnet I picked up has the right inductance to use as a loop for the AM section of this set. I tried it without doing any alignment and the reception was amazing.

This might be pretty good for AM DXing.

John

Volume Control Problem
 

I need some advice on dealing with a problem with the volume control on this set. It's a 1 meg composition pot tapped at 500K and 250K. It has a hollow shaft. The Photofact doesn't list any replacements other than Sylvania so it's pretty much going to be impossible to find.

The resistance from one end to the other is 1.2 Meg, which isn't so bad. The Symptom is that the volume jumps up to a loud leve when I start turning it up.

I've attached a scan of this section.

It seems that a spot was burned in the conductive film near the bottom of the pot. Possibly when paper cap C25 was leaky. As you go past this spot the resistance measured at the wiper jumps from 25 ohms to 250 ohms. If I measure the resistance to ground from the other taps they jump down to the correct value when the wiper is in the center of this spot. I imagine the conductive trace having a burned spot in the center of the trace, but good on both sides. I've attached a sketch of what I think it might look like.

I think the taps are there to keep the tone the same as the volume is changed. I could just short the 250K tap to ground. I'd lose a portion of the range. The tone might sound a little different. This would be the easiest solution.

I could try coating the spot with aquadag to cover the burned spot. If it's small enough, it might not be noticiable.

To get at it I have to remove the CRT, the front panel, and the plate that holds the pulley for the dial cord. I hope to avoid that.

Any other suggestions on how to attack this problem?

John

Well, the problem with the volume control wasn't what I thought it was, and the problem was fixed by an unfortunate accident.

Instead of a burned spot on the resistive trace, it was where the terminal on the ground side was riveted to the phenolic board with the resistive trace. I didn't notice that a tubular capacitor that is on the end of a coax running to the wiper of the volume control was too close to a resistor. It arced through the paint on the capacitor while I was watching and made violent discharges in the volume control. :yikes: I expected the worst. :worried: But, it turns out it just improved the connection so now the volume control tests and works perfectly! :banana:

John

While I was able to adjust the set to give a good picture, there was still a problem with the horizontal. I wasn't able to adjust it according to the service literature. Basically you're supposed to remove the discriminator tube, the 6AL5, adjust the frequency until the bar moves slowly across the screen and reinsert the tube. It should lock in at this point and then you adjust the phase.

They then have test the pull-in range by adjusting the frequency CCW until it unlocks, then adjust it back slowly until it locks in and you count the number of bars just before it locks in. Then CW and count the bars. They're supposed to be between 3-4 bars in both cases. In my case when I turned it one way it would just slowly drift across. In the other direction it wouldn't unlock until I made many turns.

I also wasn't able to adjust the phase independently.

I checked all the caps and resistors. I replaced the micas. Nothing helped. I started to suspect the horizontal oscillator transformer. But, I noticed that the DC level on the grid of the 6AU6 control tube was -1V when it should have been -3V. The 6AU6 is used as a reactance tube to control the frequency based on the output of the phase discriminator. -1V put it at one end of it's control range so it could only adjust the frequency in one direction if the free running frequency was set correctly.

The bias is determined by dividing down the -125V supply. First they divide it down to -30V with a low impedance divider then down to -3 with a 10meg and 1meg in series. I checked those and they were o.k. I was getting close to modifying it to give the right bias when I decided to swap the 6AU6 even though it tested as new and seemed to work. Well the bias went to -3V with the new tube and I was able to align the horizontal sweep as per the service manual. The grid on the 6AU6 was drawing 0.2 microamps at -1volt. My tube tester isn't going to notice that.

Now the only problem I have is with the FM. Although it worked great in the beginning, it is now fading out after 4 minutes. It runs for 4 minutes after turning on and then suddenly the volume drops.

I've replaced two micamold caps. One was leaky, the other was o.k. Some resistors are out of spec, but I don't think they're at fault.

What is curious is that the AM function works fine even when the FM has dropped in volume. They both use the same circuitry except different IF transformers and osc frequency. There must be a clue in this.

You can see the schematic for the radio section on the last page of:

https://www.msu.edu/~yurkon/Sylvania_9-2_Sup1.pdf

This is getting to be really frustrating. I swapped all the tubes in the radio after my experience with the horizontal 6AU6 but it didn't make a difference. Any suggestions for what to look for would be welcome.

I'd like to get it off my bench so I can work on my alignment generator and get it working. I want to touch up the alignment since I had to rewind one of the video IF transformers.

I'm also working on making a bezel for the 12" version of this set. A friend drew a mold up for me based on my measurements. I didn't notice however that the had made the face a cylinder instead of a sphere. It wasn't obvious in the preview. It became obvious when the shop I'm using tested their programming on a shape board.

If I'm able to cast a 12" bezel then I'll put a 12LP4 into the chassis. It should really be a 12VP4 but I'm unlikely to find one of those. I'll have to add a screen bias supply. One of the 16" Sylvania shows a circuit to do that, based on this power supply.

This is basically changing it from a 1-076 model to a 1-128 model. I have the cabinet from my family's 1-128, just nothing is left of the electronics. The 1-108 chassis was used in both. If I can't successfully cast a bezel I'll refinish the 1-076 cabinet and stick with it.

John

Have you re-capped the entire set?
Bill Cahill

Bascially. Any that I didn't change were tested. All paper capacitors were replaced. I didn't change any ugly looking ceramics based on feedback from the forum and the fact that a sample of them that I did test, tested good.

The radio section is comletely independant except for the 6AU6 1st AF and 6Y6 power amp which is shared by the TV. The problem only occurs with the FM. The TV and AM audio are fine.

There was only one electrolytic in the radio section and I changed that in the beginning since it was shorted. I changed the two micamolds that were in the radio. There are other micas that aren't micamolds. I'm hoping it's not one of these micas because I'd have to remove most of the other components just to get at them.

Also, I've checked the HV to the radio and it doesn't change. There should be 215V on the plates but it's 238V. I've tried lowering it by running the set on a lower voltage with a variac, but this doesn't change the fading.

John

Found the FM fading problem. Had to resort to using component cooler. It's the 2nd 10.7MHZ IF. It looks exactly like the Ktrans that Robert Casey repaired. I suspect it's the same problem.

Anyone have a 122-0011 Sylvania IF or Merit FM-254 you're willing to part with?

John

I found an FM-254 and ordered it, but decided to repair the original IF instead. The FM-254 would have been too difficult to use because of the pin-out.

In the first photo you can see the problem with the mica capacitor. Although it looks like silver migration might have been the problem, it was actually a break in the silver on the bottom half that you see. It appears that the mica was bent when installed. It was actually tuned to work with it open. Then it would eventually make contact as it warmed up and detune.

I measured the capacitance on the good side at 23pF. Just for the fun of it I measured the thickness of the mica which was 0.045mm, the area that forms the capacitor as 3.5mm x 5.5 mm and calculated the capacitance assuming a relative dielectric constant of 6 for mica. I came up with 22.7pF.

I installed two 22pF silver mica capacitors internally. You can see the result in the right hand photo. I think most people install them outside during the repair, but there was room and I was confident of the value that I needed.

The FM works great again and is now stable. It only took a minor touch-up on the alignment on the side that was good, on the other side I had to back the slug out many turns. I think the IF had been this way since it was made.

I'm glad that this set didn't have any serious problems to solve since it was my first restoration. Even the minor problems I had to deal with might have stumped me if not for the wealth of information that many of you have made available on your web sites.

John

John , you have done a great job .
Such a neat set to restore .
If you ever need a volume control , I "might" have one .
I've got a big box of different ones that were salvaged by a TV / radio guy back in the day.....

Thanks for the offer. So far the accidental repair by loud sparks is still going strong. I just couldn't believe my luck. I thought for sure I would have destroyed something.

John

Analog Reception
 

Since I won't have the set back in a cabinet by the time analog TV is history, I thought I should shoot a couple of photos of over the air broadcasts.

The on the left is Channel 12 in Flint Michigan, 36.1 miles away. The one on the right is Channel 6 in Lansing about 7.4 miles away. For channel 6 I don't even need a rabbit ear. Just 2" of wire.

The key-stoning you see in the right hand photo is because I'm close to the TV and at a slight angle.

I think the slight fuzziness is because I need to align the video IF. I have to finish restoring my Hickok alignment generator first.

I've also been slow in starting on the cabinet because I've been tracking down all the minor problems I could find. One was a crackling in the sound as the set warmed up. I thought I'd find that one of the electrolytics that I decided to keep was failing and I'd have to swallow my pride.

It turned out to be the 6Y6G audio output tube. I swapped it and the crackling went away. Swallowing my pride will come later.

I wonder if there is a heater to cathode short developing with it. The tube is coated so I don't think it was secondary emission from the glass.

John

Nice picture on the Sylvania! I havent forgot about the turntable John...i'll look this comming week and let you know.
-Tony

Reply test
 

I just tried to attach images and got an upload error. I'm now trying to see if I can even make a reply to my thread...

John

I can't attach files either, but it seems I can respond at least.

Mold Photos
 

Here are the photos again of the bezel/mask mold that I'm making. The left photo is the 10" bezel, the center is the 12" rear half of the mold after machining and the right is after my attempt at polishing.

John

John, how on earth did you make that mold? It looks incredible!

Thanks. I took measurements from the 10" bezel and used the radius from the datasheet for the 12VP4 CRT. I drew the cross-section that I wanted and then a friend drew it up in SolidWorks. Another shop has a new employee and they thought it would be a good training/learning experience for him. It's not a simple part even for CNC. He learned a lot and I gained a part. The risk for me was having to possibly keep replacing material if there were problems.

So, I really lucked out. I only had to pay for material. Our own shop is way too busy to even think about doing anything personal. Especially this complicated. I'd probably have gotten in trouble for even asking.

I was looking at having a rapid prototype company do it, which would have cost a fortune, when this opportunity came up.

The polishing I did by hand using micro-mesh mx and wet sanding it through all the grades, then using Mother's aluminum polish. I was worried that it wouldn't work as well as Simichrome or Wenol polish, but it seems to work as well.

John

When You Wish Upon a Star
 

More miracles. Or maybe there are more early Sylvanias out there than I realize.

Roger Dreyfoos noticed my attempt at making a mold for a 12" bezel and remembered he had picked up some freebies of some sort at CHRS flea market. It turned out one of them was a 12" NOS Sylvania bezel for the 1-108 chassis! He was kind enough to pass it along to me. Thanks Roger! :banana:

I will finish the mold, just to see if it works. Also in case anyone should need a 12" bezel similar to this.

Now I can complete my goal of having my childhood TV console again. I just need to pick up the 1-128 cabinet from my brother's place. Of course I'll have a 1-076 cabinet that's empty. No aquarium for it though. I'll just hang on to it in the hopes that I eventually find a chassis for it.

I can't blame my dad for converting his to a linen cabinet. It was a perfect use for it and he did a great job of installing the chassis and record player into the rec room. It's only when things get old that we start thinking about preserving them in their original form.

"The Wonderful World of Disney" was one of my favorite shows that I watched on the Sylvania. I've been hoping for many years to eventually find a set and the way things finally started to fall together it seemed as though a wish was being granted. Thus the title...

John

I forgot the attachments. Here's the 10" and 12" bezel.

John

I picked up cabinet from my parent's 1-128 Sylvania over Thanksgiving. It survived the trailer ride well.

http://www.videokarma.org/picture.ph...pictureid=2896

The console is supposed to look like this:

http://www.videokarma.org/picture.ph...pictureid=2897

Here's the outside front:

http://www.videokarma.org/picture.ph...pictureid=2891

The finish isn't too bad. Where it's thin it has a more reddish color.

http://www.videokarma.org/picture.ph...pictureid=2894

My dad had converted it into a cedar chest to store linens.

http://www.videokarma.org/picture.ph...pictureid=2893

http://www.videokarma.org/picture.ph...pictureid=2892

Restoring it to use the 1-108 chassis that I have that is common to the 1-076 10" and 1-128 12" consoles shouldn't be too difficult.

I had ordered some NOPP film from a US company, but the actual shipment came from Jakarta and was boxed in some fairly high grade luan/mahogany plywood. I'll see if that works for the panel. I also need to pick up some small pieces of solid mahogany.

The biggest problem is that he cut slots in the trim for the cedar.

http://www.videokarma.org/picture.ph...pictureid=2895

Since the finish is so dark, I may be able to just fill it and stain it. The recent thread on molding trims/molding will be helpful here.

If you were really observant you'll have noticed that there were supposed to be rosettes at the upper corners which don't appear on my cabinet. I vaguely remember them being there, but there are no signs of them being removed. I think they would have been attached rather than milled into the boards. The rosettes are raised and it would have required milling much wood away. They may have even been metal like the pulls.

The style of this cabinet is Hepplewhite, or so claims Sylvania.

I'm getting closer to getting my childhood set finished. I may convert the 1-076 cabinet into a cedar chest using the cedar from this cabinet after I'm done. I'll never be able to find parts to make a complete 1-076 or 1-128 without gutting one of them. Fortunately, beside the cabinet the only things that are different between the two are the CRT, band to clamp the CRT, and the bezel.

John

You are doing an awsome job John. When this is finished you will accomplished something very wonderful, especially considering the obsticles that have been in your way.

This is the first I have seen the postings about the mold you had made. What a spectacular piece of machining. Must have taken a lot of work to polish that to such a beautiful mirror finish.

If you look around at some of the woodworking web sites, I think you may be able to find wooden rosettes that might approximate the ones that are missing. Just google wooden rosettes. The first hit I got can make 13,000 different historic designs.

Bob

Are there pictures in post #65 that my browser does not see?

I'll second that.
 

Same "no pix" problem here. Maybe they didn't survive the trailer ride? I PM'd John.

Roger

Yes there are pictures. This is my first attempt at posting using images from an album. I thought I could leave the album private. Apparently not, so I've made it public.

Please let me know if this works now.

John

Looking good now! Nice set!:banana::banana::banana:

jr

I've got the pix.
 

I've micaculously got the pix now. Now here's my opinion. You don't need no stinkin' rosettes. Seems quite possible that someone decided (perhaps at the factory) that it looked as good or better without the rosettes.

Or, maybe the Sylvania legal department decided that as add-ons, a little kid could figure out how to take them off and swallow one.

One person's opinion,

Roger

After looking more closely I can see where one was glued to the left side. I don't see any evidence on the right side.

I'll leave this for last and decide then which way I prefer it. I tried a quick search per Bob's suggestion. I need to find one that's 3/4" in diameter. Most seem to be much larger than this.

John

I've started to remove the cedar lining. Fortunately my dad didn't glue them in. They're tongue and groove and were nailed as you would flooring with small brads. The nail holes are almost invisible.

I was happy to see the tube chart is still there. I'm a bit confused though. They went to the effort of making a label especially for the model 1-128. That uses a 12" CRT. Yet they show both the 10" 10MP4 and 12VP4 as possible CRTs. Why show the 10MP4 when it was used in the 1-076?

It's also curious that the "UL" label was inked out. I wonder if it didn't meet UL certification?

I'll take more photos after I remove all the cedar and figure out what's missing. I found one surprise already. Maybe it'll be clear after I remove more cedar.

John

Hmm, that is weird. Never saw a UL label inked out.

The finish on that cabinet doesn't look bad at all. I'd bet a little touch up (and maybe a couple coats of lacquer if it's worn) would do wonders.

Well, I checked the 1-076 cabinet and the UL stamp is inked out on it too.

The first picture on the left is the inside of the phono side in the 1-076 cabinet. The rear panel is Masonite. I was surprised to see that they used regular plywood on the right where they separated the TV from the phono. The left side is mahogany veneer. In the 1-128 they used mahogany veneer on the right side too. I had thought they would also use it for the back, but I think Masonite might actually look better because of the uniform surface. The color of the Masonite looks much different than the wood in the photo, but to the naked eye they are quite similar. Looking at the photo in the Sam's, it appears that they used Masonite in the 1-128 model also.

But, the record changer is supported differently. In the 1-076 it hangs into the speaker cabinet. In the 1-128 it's above the record storage area and sits on a platform. The board to support the changer fits into a dado on the right side and is screwed to a rail on the left side. It also sits on a board at the front of the cabinet. I'm not sure if they used Masonite or plywood which sat on the bottom rails to separate the space between the changer and the storage area.

The photo on the right shows the rosette that is on the 1-076 cabinet. I believe it's the same as the missing ones on the 1-128. I suppose I should make a mold of it to replicate it. However, I'm tempted to get a Carvewright to make one out of wood. But, unless I can come up with a number of other uses for the Carvewright, that would be a silly expenditure.

John

Roger Dreyfoos suggested that the rosette was made of Repwood and not carved. After examining it closely, I'm pretty sure that's correct.

That will make it easy to reproduce and has killed my immediate desire to obtain a Carvewright. I've ordered some Equinox 35 silicone putty to take an impression and make a mold.

I've also ordered some Mohawk toning lacquer in three different shades of mahogany to try out. Hopefully one will match the existing finish.

John

Here's a test of making a mold to copy an appliqué. I decided to try it on an appliqué on a Majestic 71 radio. It's about 1" long. The radio was refinished by the previous owner and that might account the the old finish around the piece.

I mixed up Equinox 35, which is a silicone putty and applied it. I removed it after letting it sit for the demold time of 7 minutes. I was surprised to see that no air was trapped.

I then mixed up some Bix staining putty and used that to copy the piece. The rough surface is due to micro bubbles that I didn't realize had formed when I added the water and mixed up the putty. If I use this in the future I will need to degas it. Otherwise I might use an epoxy instead.

The final photo shows the part next to the original after spraying with lacquer. The difference in color is because I only had mahogany toned lacquer when the original is walnut.

The rough surface is unacceptable so I will need to work on this some more, but the mold was easy to make and is more than satisfactory.

John

Awesome! Where did you get that Equinox 35?

I got it from TFB plastics since they're close to me.

http://www.tfbplastics.com/catalogse...inox&x=25&y=10

The manufacturer is Smooth-On http://www.smooth-on.com/Architectur...236/index.html

John

I've been holding off replacing the 10MP4 with a 12LP4 since I was having trouble finding the right CRT socket. I collected a bunch of brighteners to steal the socket from, but they are quite identifiable as brightener sockets due to the green cap and mediocre quality. I would have had to splice the leads also which I didn't like the idea of doing.

I finally obtained a NOS EBY CRT socket. It has nice long leads and looks like it belongs. It does have an extra lead for CRTs that use electrostatic focusing. So, I have the option of cutting off the blue lead or running it down to the chassis and just not using it. For some reason, I'm inclined to do that. Some day I might find a 12VP4 and then I'd put the old socket back. And I could save the new socket in case I come across a set that needs it.

I finally had to give up on my old Pioneer RPTV. I replaced it with a 60" Mitsubishi DLP which I mounted on the wall. I now have space to put the Sylvania console under it. I'll bring the cabinet in this weekend and be able to work on it when time permits.
John