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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Sat 25, 2020 7:55 am 
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Yes Sir. Electrical Engineering. Something I wanted to do all my life.

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Sun 26, 2020 1:53 am 
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Knowing how to build and repair things is a valuable asset to an engineer. A lot of university students think that engineering is all about computer simulation (I wonder where they got that idea?) A simulation is only as good as the data entered. When do you ever know EVERYTHING about something? But the purpose of a factory is to build stuff. Beyond the simulation, you have to know how to make it work in real life. And then, you have to know how to find out what went wrong when the production line suddenly stops because the product doesn't work anymore. I had to do all of that, more than once.

When I used to interview people for engineering jobs, I would always get about 25 resumes from applicants. Almost all of them had straight A averages. But when I read about their outside activities, I found that they coached soccer, worked in a bakery, or did all sorts of things not related to electronics. Once we hired someone with a C average over those with A averages because he had installed car stereos; at least he knew what to do with a wire. Another time I interviewed someone who was very proud of making a circuit with a microprocessor that would turn on red, yellow, and green lights like a stop light. I can do that with a slow speed motor turning a wooden wheel with contacts around the edge. Another would-be candidate told me about making a robot that would follow a line. When I asked something about the parts they used they told me they had only simulated it. Another person was interested in an opening we had for a digital engineer. I showed them part of the schematic for one of our products and asked how they would upgrade it to the latest revision of USB. When they didn't know, I suggested that they find the USB connector and see what it connected to. They couldn't find the connector even though it was labeled. Need I go on?

Experience counts. Get lots of it and make sure it gets on your resume. And include stuff like finding replacements for unavailable parts. I had to do this too, many times.

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Sun 26, 2020 6:40 am 
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Thanks Jim! Got almost 13 years of experience in electricity. Started making simple circuits from a kit my parents got me when I was 4, Got Snap-on-Circuits when I was 6, and experimented with what until I was around 9. At that age, I was reading about the history of the transistor, and "discover" that all popular, vacuum tube. Since then, I have scrapped and repaired/restored many radios, televisions, and even computers. I gather up all the parts I can find, to design and repair these sort of things now (Much to my parents disapproval, going so far to call it "junk", which, indeed, some of it is, but I digress :roll: ).

But anyway, Simulations and college problems, are never going to cover all the problems one may encounter as stated above. That's where experience comes in. May not have as much as some, may be a little slow, but I have it.

Thanks Y'all!

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Thu 30, 2020 8:13 pm 
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Update: The Picture looks Beautiful, Except for 3 things. There is AC Hum in the picture, the Vertical Linearity is off, Stretching 2/3rds of the picture, and a weird Horizontal Ringing problem. The AC Hum can be counteracted by putting a better choke in the B+, the poor linearity may be a caused by the AC Hum, and the Horizontal Ringing may be due to leakage of insulators, so that will have to addressed.


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Television Picture.png [ 976.7 KiB | Viewed 638 times ]

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Thu 30, 2020 9:24 pm 
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Is the main B+ supply half wave or full wave?

There most likely will be a vertical linearity control which needs to be adjusted or it could be a circuit problem if adjusting the control doesn't fix it.


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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Fri 31, 2020 7:42 am 
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Half Wave. It contains no large Power Supply transformer. Rectified directly from the 120V with the original part number thermistor before the diode and a fuse after the power supply.

P.S. I am trying a new 1H Choke. And your right about the linearity. Probably going to have to sub some capacitors and resistors in the vertical section.

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Fri 31, 2020 11:52 am 
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Oh ok.

If the 1H choke doesn't do it you can increase the value of the filter cap after the choke.

Also I've seen some chokes use a capacitor in parallel with the choke and it filters better. Am thinking the cap value is chosen to where it and the choke forms a higher impedance path for the ripple voltage.

I'd figure the vertical might need component values tweaked especially if you used a yoke other than the specified part number.


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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Fri 31, 2020 6:52 pm 
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Alright I had done something like this. I put a 300MFD 150V capacitor after the diode, followed by the 1H Choke, then a 680MFD 200V capacitor, and then the fuse. It worked, and there is a negligible amount of hum. The Picture has no rolling bar now. The Linearity is probably the last thing I will tackle. I am trying to solve the Horizontal ringing first.

The Yoke was a Pain in the rear to find. Sam's said that the yoke was to be a 67MH-Vertical/23MH-Horizontal Yoke. It also gave some references on the yokes. Thorardson yokes are by far the most common yokes out there, So I went looking for the yoke (Type Y-66) they specified. It may be a Typo, or a rare yoke, as I was not able to find that one. So I cross referenced the Triad Yoke Part number (Type YT-103-1) to a Thorardson yoke, Which is the Y-105. That one is a 70MH-Vertical/26.5MH-Horizontal Yoke. Very Similar, and not much to go wrong. It had some resistors and capacitors in the yoke that were not in the original diagram, so I clipped those out.

Here is the Sams: https://ia600903.us.archive.org/23/items/RCATVSchematicAG029AAG029BAG029EAG029NKCS152CSweet16Debutante/RCA%20TV%20Schematic%20AG029A%20AG029B%20AG029E%20AG029N%20KCS152C%20Sweet%2016%20debutante.pdf

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Fri 31, 2020 7:00 pm 
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Oh ok those resistors and capacitors may have been needed.


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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Jul Fri 31, 2020 11:22 pm 
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I was thinking about your statement Tube Radio, and I remember putting in a 330pf capacitor, instead of a 47pf capacitor here, to help out getting larger width. However, I got the width back width back, when I debugged a circuit error. So, I put it back to 47pf, and the ringing problem cleared up. Now to tackle linearity....
Attachment:
Ring Singing.PNG
Ring Singing.PNG [ 3.2 KiB | Viewed 608 times ]

Here is a Picture of the television with Ellen Degenerate -- err -- Degeneres, and I hope you can see the stretching. But I will solve it.


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IMG_20200731_151659_9.jpg
IMG_20200731_151659_9.jpg [ 842.28 KiB | Viewed 608 times ]

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Aug Sat 01, 2020 12:05 am 
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I see it towards the top


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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Aug Sat 01, 2020 5:45 am 
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And Now I ask everyone, What Bad Linearity?
Attachment:
IMG_20200731_215228_8.jpg
IMG_20200731_215228_8.jpg [ 738.45 KiB | Viewed 589 times ]


P.S. If you can't see it, I fixed it. Now to tackle the Audio!

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Aug Wed 05, 2020 12:09 am 
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So I got the Audio working of Friday, or Thursday, can't remember. Wasn't able to post it, as I was busy with other stuff. Anyway, Now I have to think about the Cabinet for the set now. I think I will do a Console Construction, with an AM radio (Scrapped from a 6 tube Chair side radio-phono combo), 2 speed 33/45RPM record player, and possibly a cassette tape player, If I can find one suitable. I already picked out the speaker cloth color (https://i.ebayimg.com/images/g/wooAAOSwsWpedPXF/s-l1600.jpg). The Wood cabinet is to be a mahogany wood color (https://woodwrightfinish.com/woodwrightfinish.com/wp-content/uploads/2017/07/225-mission-apple-mahogany.jpg). The picture tube Bezel is going to be a pain in the Derriere. I am thinking about casting it from tin or another light, easy to melt metal. Anyway, will leave ya with that.

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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Aug Wed 12, 2020 5:44 pm 
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Very impressive work! Regarding the bezel, perhaps something can be 3D printed or vacuformed?


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 Post subject: Re: UPDATE: RC-30 Manual Homemade television
PostPosted: Aug Wed 12, 2020 10:02 pm 
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Thanks Tym! I thought of drawing the shape of the picture tube on a piece of plexiglass (Lucite) and spray painting the edges gold. Then put it in from of the picture tube to act as a decoration and protection. I drew out the cabinet.
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HPSCAN_20200812204411763.jpeg [ 437.13 KiB | Viewed 429 times ]

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