These days we don’t get too fussed about miniaturized electronics, not when you can put an entire processor and analog circuitry on a chip the size of a grain of sand. Things were quite different back in the 1980s, with the idea of a credit card-sized radio almost preposterous. This didn’t stop the engineers over at Casio from having a go at this and many other nutty ideas, with [Matt] from Techmoan having a go at taking one of these miniaturized marvels apart.
On the chopping block is the FM stereo device that was featured in a previous episode. Out of the four credit card-sized radios in that video, the one with the rechargeable battery (obviously) had ceased to work, so it was the obvious choice for a teardown. This mostly meant peeling off the glued-on top and bottom, after which the circuitry became visible.
In addition to the battery with a heavily corroded contact, the thin PCB contains a grand total of three ICs in addition to the analog circuitry. These were identified by [Spritetm] as an AM/FM tuner system IC (TA7792), an FM PLL MPX (TA7766AF) and a headphone amplifier (TA7767F), all of them manufactured by Toshiba.
Although [Matt] reckons this was a destructive teardown, we’re looking forward to the repair video where a fresh cell is soldered in and the case glued back together.
the super thin adjustable capacitor is interesting
Defo! Any sources and specs for this part?
I think same. It could also be a flat potentiometer, however.
By using a varicap diode, an variable capacitor can be emulated through a variable resistor (potentiometer).
Newer radios did use that trick. That being said, I prefer the classic variable capacitor.
Not only newer radios: Variocap – diodes have been used in miniaturized tuners since the early 1970s, replacing bulky mechanical variable capacitors. At least where low max. capacity was sufficient (FM etc.). Even my 1972 “Kosmos XU1” radio experiment kit already featured a tiny variocap. It was used, among other things, to tune a simple FM receiver with a potentiometer. Beeing voltage controlled, it allowed for tricks like automatic station scanning.
Hi there, the 1970s is already new to me, in terms of radio and TV technology.
By the 70s, b/w portable TVs started to use internal power supplies as standard and integrated circuits for the flyback control.
By old, I’m thinking of radios from 1920s or 1950s, rather.
My grandma’s Braun SK2 radio had tubes and a real variable capacitor (“Rundfunk Drehko”).
Crystal radio sets and pocket radios of the 80s and 90s still used conventional variable capacitors, too.
The compact plastic models with multiple pins of capacity that could be combined for bigger capacity.
Here’s the type I mean: https://commons.m.wikimedia.org/wiki/File:Universum_UR_1886_-_tuner_part_-_variable_capacitor-2252.jpg
Real OGs know that in the 20s there wasn’t capacitors.
They where condensors.
Same content was published 4 days ago by Al Williams.
No, I had said I wished he would do a teardown. Now, he’s done a teardown!
Mea culpa Maya and Al, I had read Al’s article, but here I jumped to conclusions just by looking at the picture.
Yeah John. Didn’t you read the article?
Those Tantalum caps are probably bad also, they love to short in their old age.
Considering the end result of the teardown I’d think bad caps would be the least of your worries.
This is beautiful. I’m getting a throbbing nostalgia.
That’s some truly impressive miniaturization given the era. Learning how they managed to flatten out that adjustable cap would be fun.
They had even smaller SMD parts at the time (late 80s).
Wrist watches had used them, for example.
From an economical point of view, these chubby SMD parts were small enough though.
The CR2032 coin cell and the 2,5mm jack did define the thickness of the radio card, so it was okay.
The follow up video we all needed!
I think some hot air and even solvent would make it servicable to some extent? I wonder if that spring was actually an inductor that had broken off that might explain the whistling output from the first video.
I do like the teardown, very interesting.
But I can’t stop thinking about the destructiveness of it. Surely a hairdryer or a hot air station would have softened the glue, after which the sides would have come of without ripping them to pieces?
Yeah, I found myself skipping the ripping off of the labels as it was too painful to watch. Matt really should have borrowed the Ms’ hairdryer…
He was probably also being a bit frustrated and not in best health (a cold?),
so it’s perhaps understandable from a human point of view..
So maybe he just wanted to finish this topic and show us the insides of the radio.
It’s just a thought of me, however. I’m just thinking out loud.
Dude looked like death warmed up in his last video. First upload in a few months, apparently he’s had the flu.
I think everyone’s reaction was “Holy crap, WTF happen to Techmoan?”
While Matt does from time to time dabble with a soldering iron, electronics and precise repairs is not his field of expertise. Anything that can’t be fixed by restoring a broken trace or replacing all the electrolitic capacitors is out of the question, so for all purposes this device was already dead. I appreciate a lot the Techmoan channel, that’s why it’s in my subscriptions, but more for an historical and cultural angle than for a technical one, and that’s where it shines.
And the Techmoan channel really does shine. I have plenty of places, including youtubers to look to for technical expertise, but Techmoan is wonderful for the history and the depth and breadth of his reviews of home electronic and entertainment gear.
Without any exaggeration, I’m genuinely concerned that Matt’s deteriorating health is starting to manifest in a decline in his cognitive abilities. This wasn’t the first time he mindlessly destroyed something completely unnecessarily with an improper approach when the solution was in plain view.
Here, he needlessly ruined a historical artifact that could have been disassembled non-destructively (using the same techniques used to take apart smartphones today) and easily repaired.
To top it off, he forcibly snapped off an entire piece of the plastic chassis while rambling about strong glue and the Cybertruck, even though it was blatantly obvious that the part was held in place by melted plastic posts (I’m not sure of the exact English term for this).
It genuinely makes me feel like Matt’s cognitive abilities have taken a hit lately.
Sounds like the villagers should get together, light some torches and storm Matt’s croft. How many people will he kill with his careless lasers?
Without any exaggeration? He ruined something that was broken and never going to work. Just because he doesn’t care about this “historical artefact” doesn’t mean he’s in a cognitive decline.
Historic artifact? They made these by the thousands. They’re collectibles, but not priceless rarities. It’s not like he took an axe to that Nintendo PlayStation prototype. By all means worry about the man’s health, but do so with empathy, not needless aggression.
What an incredibly odd comment to make. Did your mother never tell you to say nothing if you have nothing nice to say? – Context here: People asked him to tear it down, the thing was broken and they made hundreds of thousands of these things over the years. I think you would be better off directing the focus of your angry comments towards more productive things.
Wow. …. Wow.
go on ebay and buy your own, whole tens of dollars!
Wow. That is probably the rudest comment I’ve ever seen on HaD.
Give Matt the benefit of the doubt, he’s clearly recovering from a pretty serious illness. Also he’s not a professional repair technician and it was already non-functional and of little value to him so he just wanted to do a quick teardown (in the literal sense lol). Would I prefer to have seen him properly take it apart, repair it and put it back together? Sure. Am I really all that bothered that he’s taken some shortcuts while he’s obviously still not feeling 100%, honestly not really and in a similar situation I’d probably do the same thing in a fit of frustration.
He just went through a very nasty flu for about a month and seemed to have lost a lot of weight.
Now if you lose weight like that it would indicate he could not eat properly due to the illness and in my personal experience, and related stories I heard from others, that in fact can noticably influence your brain (memory is one of the things that is impaired) until you recover.
Although his impatience was more a general one in my view. Note how he also says something like ‘the reason I don’t use a proper screwdriver is simply that I can’t be bothered to get one’ indicating his state of mind and his awareness of such.
So I’m not too worried about his mind.
I’ve got one of those somewhere and I got it open years ago safely because it was dead and it worked then, battery?