When [Dr. Moddnstine] saw a 1978 General Electric TV in the trash, he just had to save it. As it turned out, it still worked! An idea hatched — what if he could turn it into a vintage Chromecast TV?
He opened up the TV and started poking around inside. We should note that old TV’s are pretty dangerous to open up if you’re not familiar with the components inside — high-voltages that could kill you linger on some capacitors. [Dr. Moddnstine] didn’t go into too much detail, so do a little extra research before you open up a TV.
Part of his goal for this project was to keep everything self-contained within the TV so all you would have to do is plug it into the wall in order to use it. Since the TV is so old, it doesn’t even have an analog RCA connections for a video input — just a VHF input. Because of this he needed to use three separate connection adapters to get the video signal to the TV.
First step was an adapter for HDMI to composite video, then composite video to an RF modulator, and then the coaxial output from the RF modulator to a two-lead VHF plug adapter. Phew. We’re surprised he found enough space inside of the case to fit it all in!
We’ve shared a lot of retro TV builds over the years, but this is the first one we’ve seen that utilizes a Chromecast. Most use Raspberry Pi’s, and some versions that just replace the old tube with a brand spanking new LCD!
[via r/DIY]
I have roosting here its B&W relative…… Nice though.
If anyone is going to have a go at this sort of thing, please be aware some old TVs had live chassis, that is, there was no mains isolation transformer so they can really be a death trap! If you find this, use an external isolation transformer when working on them, and DO NOT connect external Ethernet, USB, audio…..
Keep safe.
In fact, if you watch the long version of the video, there’s a lovely label “WARNING: THIS CHASSIS 70 VAC ABOVE GROUND, USE ISOLATION TRANSFORMER WHEN SERVICING. 738141821-1”
Yeah a friend had this Ancient NEC Behemoth, signal was extremely grainy even though other TV’s were good on the same whip the ring had been stretched and the center part of the socket for the PAL RF was looking like a working girl after accommodating several elephants quick squeeze with Needle nose NOPE It’s peanut butter SHOCKING TIME fell backwards onto floor damn 240v stupid no grounding damn old dangerous people.
Properly implemented Ethernet has 1.5kV isolation.
Or.. you could just rewire it to not be that way anymore…
The hack here is fitting it inside the chassis. A better hack would be to “simply” find where to inject the composite video after the demodulator in the TV, and ignore the RF Modulator and un-balanced to balanced balun.
And tat sort if thing was described in Don Lancaster’s “TV Typewriter Cookbook”, which he may have put online. Probably warnings about shock too. Though it came out in 1975, when most could only afford B&W set for a monitor, so the book my be less detailed about interfacing to color sets.
That’s the advantage of through the antenna jack, there is isolation, and no fusing inside the set. The disadvantage is that the text on the screen will not be as sharp.
For a while, it was so common to modify tv set. There was at least one article that used opto-isolators to provide a video interface to a tv set.
Michael.
This book is incredible. Full of epic hacks, highly recommended!
sometimes that is not possible as ic’s tend to hide that path from you. I have a nice b/w Panasonic TR-5030S and there is no composite injection possible there.
I did this exact thing with an old panasonic TV I had. I recall having to use some kind of serial decoupling cap. Worked great for many years as the monitor for my C64. Including that time I built a pre-GPS in-car navigation system for my VW bug. (Took up the whole passenger footwell…)
I think I had the schematics in-hand somehow as a guide, but one option is to feed the TV RF somehow and carefully poke around with a scope until you see a signal that looks like composite video. The board layouts in the old days were usually pretty well organized.
“…saw a 1978 General Electric TV in the trash”, the fact this still happens is upsetting.
Should have converted from hdmi to rgb +sync and connect sync to appropriate pin(s) found with 15 minutes of googling for datasheets. RGB straight to video amps, typically found on the neck board. That is if the chassis is isolated.
Why not just hook up the Chromecast to a short range NTSC transmitter, no fuss, no muss and no need to fool with the internals of a TV that you either want to keep as is (an old 50’s model) or could kill you if it wants to be mean.
Because in the US at least, unless you’re a ham, transmitting television wirelessly is thoroughly illegal without a license. There is no Part 15 carve-out for television as there is for radio.
True, but my transmitter only goes about 200 ft and I use channels that haven’t had a license since 2007. None of my neighbors have complained that their channel 9 snow is now showing video.
If you can find the chip responsible for the video processing, and then find a datasheet, the chips have a pin for composite video. Maybe not on these older sets, but my 5″ B+W sets from the 80s and 90s do.
Wish he’d replaced that power supply cap while he was in there… recapping the whole thing is probably overkill, but the power supply capacitor was right there when he had it open. Would save the whole set from eventual loss of magic smoke…
Confused on the RF modulation used here. Modulators usually output channel 3/4. TV tuner is channel 10?