Author Topic: EEVblog #830 - Portable CRT TV Retro Teardown  (Read 11525 times)

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Offline EEVblog

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EEVblog #830 - Portable CRT TV Retro Teardown
« on: December 16, 2015, 03:24:21 pm »
Take a look inside a vintage 1984 B&W National CRT portable TV

 

Online richfiles

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #1 on: December 16, 2015, 05:25:16 pm »


I have a portable CRT TV that's MUCH bigger than this one, but with one notable feature...
It has a color CRT! And it still works! I want to get one of those cheap Raspberry Pi Zeros to connect to it and do "Mission Control" style "transmissions" for kerbal space program. I'd then install the CRT into the custom controller/cockpit I'm building.



Aside from that bit of awesome, old camcorder viewfinders had incredibly small CRTs. Those are also super easy to inject a composite video signal into!
 

Offline SpidersWeb

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #2 on: December 16, 2015, 05:38:46 pm »
Awesome. I have a color portable from around the same time, although mine is huge in comparison. For testing I used an old VCR with RF-out hooked to the antenna input.
I spent most of the video trying to spot a dodgy electrolytic but didn't spot anything.



 

Offline SeanB

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #3 on: December 16, 2015, 06:30:21 pm »
Going to be either leaky caps or a dead SIL package. Matsushita capacitors of that vintage do not bulge when failed, they were designed to just hold it all in, and they commonly simply reformed away the electrolyte and the hydrogen diffused through the seal and escaped, leaving behind a high ESR and a dead capacitor. 30 years plus old and at least a few will be leaky, especially the one doing the horizontal scan, as the scan has shifted so the coupling bipolar capacitor has leakage.

The nice thing about these old sets is that the tuner module output has a standard video signal as output, though it will be inverted, and then it goes to the video amplifier, sync separators and sound IF. Thus you can cut a trace and put in a single transistor inverting amplifier and use it with external video. Then it can be used as a simple monitor.

Must pull out the JVC colour portable I have, it uses a similar scheme, and the manual for it actually had the full service documentation and a circuit diagram inside.
 

Offline miguelvp

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #4 on: December 16, 2015, 06:31:45 pm »
I have a jvc cybercam gr-dva1u that someone gave me because they where junking it.

Want to reuse the optics and motor drivers with an HD webcam, and it does have a color CRT viewfinder (probably takes composite input) I did take it all apart to get it to work (mini DV tape was stuck and no charger for the battery) but after I put it back together and testing that it worked I did put it aside.

It's on the low priority bucket right now.

The CRT probably doesn't require a lot to power it up.
 

Online richfiles

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #5 on: December 16, 2015, 06:49:38 pm »
Lucky!  ;D
I've been looking for a color viewfinder CRT for years, and never seen one. I only have the B&W ones. That color portable is certainly a nice find for me, but I TOTALLY wish i could find a tinier one one of these days! Those things are so fun for little odd projects.

I wish I still had my old N scale model train layout... I thought it was stored in my storage unit... but it wasn't... and I had moved...  :'(
i was TOTALLY gonna make a drive in theater with one of these... Loop "Plan 9 From Outer Space" on it or something!  :-DD
 

Offline miguelvp

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #6 on: December 16, 2015, 07:00:09 pm »
Well, I was wrong (my wife loves it when I say that)

According to this:

http://www.cnet.com/products/jvc-gr-dva1u-camcorder-mini-dv/specs/

the viewfinder is LCD based. I took the thing apart but not the actual viewfinder encasing.
 

Offline f4eru

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #7 on: December 16, 2015, 07:34:49 pm »
When dave says : "nobody used it in the train, it's only a gimmick"
Not so in Japan !!
It probably was a hit in commuter trains in Japan.
Even today, TV airs special signals for TV on Keitai (phones).
About every third phone has TV (at least on my last trip there, in 2009)
 

Offline rs20

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #8 on: December 16, 2015, 10:09:34 pm »
I was watching this on my more-than-HD colour smartphone, when I realised how incredibly symbolic that was in terms of the technological progress that's happened over the past 30-or-so years...?
 

Online richfiles

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #9 on: December 17, 2015, 01:27:50 am »
Given the shape, it's likely the specs are being redundant,a nd only mentioning the flip out view screen device... It's I guess, possible, but the length of the viewfinder really screams CRT. The optics and backlighting, and poor resolution of an LCD that small would be horrifying, most likely.

Another common thing, was to have a B&W viewfinder for traditional use in bright sunlight, and the flip out color LCD for indoor use. It could still be color though... You'll just have to check it out.
 

Offline Hydrawerk

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #10 on: December 17, 2015, 03:44:27 am »
I have a Elektronika VL-100 TV set. It was semi-operational back in 2012 or so. It was filmed in 2012 or before, i am not sure. Nowadays the tuner cannot receive any TV broadcast.
The whole unit is shown later in the video.
« Last Edit: December 17, 2015, 03:46:27 am by Hydrawerk »
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

Offline drussell

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #11 on: December 17, 2015, 04:56:49 am »
Just get a good pro-type modulator like a Blonder Tongue and stick an antenna on it.  Feed in the video source of your choosing and enjoy TV around your home (/ yard / neighborhood, depending on how high you crank the output power and how good your antenna is) with your retro-portable!  :)

Just don't turn it up TOO high or you'll be visited by your local signal police!   :o

 

Offline TheSteve

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #12 on: December 17, 2015, 06:43:49 am »
Ahh, the Russian woodpecker makes an appearance!

Hmm, why is there no dedicated ham radio forum here, there are likely enough of us to make it worth while.
VE7FM
 

Offline Alex Eisenhut

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #13 on: December 17, 2015, 12:32:07 pm »
Super awesome. I have a Commodore SX-64, which has a color CRT mashed into a heavy luggage-like portable computer.

Flat CRT info here:

https://en.wikipedia.org/wiki/Aiken_tube

http://blog.modernmechanix.com/flat-screen-tv-in-1958/
 

Offline Tek_TDS220

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #14 on: December 17, 2015, 02:42:52 pm »
It's amazing to me that this TV draws only 1.8 watts.  It needs high voltage, has a filament, not to mention the semiconductors.   

The batteries must not have lasted very long, but maybe enough for 2 Twilight Zone shows.  The old carbon-zinc AA batteries were about 0.65 Wh, so maybe a little more than an hour if the TV drew a constant 1.8 watts.
« Last Edit: December 17, 2015, 02:46:01 pm by Tek_TDS220 »
 

Offline Tothwolf

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #15 on: December 17, 2015, 03:56:09 pm »
Going to be either leaky caps or a dead SIL package. Matsushita capacitors of that vintage do not bulge when failed, they were designed to just hold it all in, and they commonly simply reformed away the electrolyte and the hydrogen diffused through the seal and escaped, leaving behind a high ESR and a dead capacitor. 30 years plus old and at least a few will be leaky, especially the one doing the horizontal scan, as the scan has shifted so the coupling bipolar capacitor has leakage.

Leaky not just electrically, but also in the physical sense. Watching the video in HD, it looks like all the black 6.3mm Matsushita capacitors are leaking from their bottom seals with visible corrosion of their leads and nearby components, including some of the pins on the vertical deflection IC.

A complete replacement of all the aluminum electrolytics and cleaning to remove any electrolyte residue and corrosion would be the first things to do to restore one of these to functional condition. Most likely that's all it would take to get it working again.

The larger 8 and 10mm Matsushita capacitors also have a date code stamped on their tops which can be decoded.
 

Offline fubar.gr

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #16 on: December 17, 2015, 06:58:18 pm »
Dave, I see you're wearing your Australian safety boots again!  :-DD

Offline VK3DRB

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #17 on: December 17, 2015, 11:05:49 pm »
These TV's were very good for hacking. I once hacked a similar low cost tiny black and white portable TV to convert it into a signal strength meter for TV antenna alignment.

I tapped off the RF AGC voltage and devised a voltage to AF frequency converter circuit using 6 transistors. There was also a buffer circuit to drive a moving coil meter. The end result was what I reckon was a better meter in some ways than a commercial unit costing thousands of dollars. I would plug the tiny TV into the household antenna socket, connect a walky-talky with the PTT locked down and climb up on the roof and adjust the antenna for the highest audio frequency, heard through another walky-talky. Hence I would adjusting the antenna on UHF channels for the highest signal strength ensuring they were pointed directly at the transmitting towers. I could also use it near the antenna to see ghosting on the picture tube and read the meter. It worked a charm.

To help pay the mortgage, I decided to run a business on the side putting up antennas using this machine where we installed about 200 antennas in 8 months during the government's TV station equalisation programme in the early 90's. This hacked TV proved to be an invaluable tool for installing TV antennas.
« Last Edit: December 18, 2015, 09:44:40 am by VK3DRB »
 

Online richfiles

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #18 on: December 18, 2015, 07:21:16 am »


Colliers did an incredible article back in September of 1954 on "Stereatronics"... The word never took off, mainly cause the writer spun the term as a "fancy" way to refer to solid state electronics. Back in 54, solid state was the new, cutting edge concept. Transistorized radios, and such, but manufacturers were researching many potential applications, and quite frankly, the article delves into an incredible vision of where the industry believed the technology would eventually lead int he future. While there are CERTAINLY a few dud predictions... like the "Irradiated Food Locker"  :-DD they got a LOT of it RIGHT!

The thing that stood out as the most poignant shocker in their disturbingly accurate vision of the future, was a GE television concept that used an early concept of EL lighting, with a grid of fine wires to form the pixel matrix. The pixel matrix was scanned just like in a modern OLED display to excite the phosphorescent element at the point of intersection. It looks almost identical to my Samsung LCD, just playing an old sepia toned movie. It looks like there are some manner of ventilation openings at the top and bottom, and quite frankly, I can't tell if that was a mockup for the photo, or it it was real or not... Regardless, they had the right idea, and the prediction is one of the most stunning I've ever seen! I own an original copy of the magazine... Cigarette and booze adds... and the most accurate future tech prediction I've ever witnessed. They go into a lot of projections, and truthfully, a lot of them actually DID end up happening! Solar powered homes, inductive charging/power, automatic garage door openers, child monitors, door cameras, remote controlled toys, remote controls for the TV, flat panel TVs that could be hung on the wall, VCRs, automated HVAC, automated lawn watering, solid state lighting, miniaturized hearing aids... and more. they call item #18 on page 69 a "computer", but I actually am quite familiar with that particular design... It's a prototype electronic calculator, made in 1954. It's crude, but that is actually what it is! Number entry is actually by means of a ROTARY telephone dial, and a rotary switch to select the digit place. It consists of a couple of decade counters with a carry function.

http://blog.modernmechanix.com/how-solid-state-electronics-will-change-your-life/
« Last Edit: December 18, 2015, 07:24:41 am by richfiles »
 

Offline nathanpc

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #19 on: December 20, 2015, 04:18:46 am »
I think this would make an interesting repair and hack video.
 

Online RetroSwim

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Re: EEVblog #830 - Portable CRT TV Retro Teardown
« Reply #20 on: December 25, 2015, 08:51:10 pm »
Just get a good pro-type modulator like a Blonder Tongue and stick an antenna on it.  Feed in the video source of your choosing and enjoy TV around your home (/ yard / neighborhood, depending on how high you crank the output power and how good your antenna is) with your retro-portable!  :)

Just don't turn it up TOO high or you'll be visited by your local signal police!   :o

There was a wrist-watch TV on Mike's Electric Stuff, and he just used an off-the-shelf digital STB. He stuck a wire into the RF-out on the STB, and wrapped the other end around the TV's telescopic antenna (i.e. world's worst inductive coupling) and it worked well enough for the demonstration.
 


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