Curiosity teardown: cable TV box
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- Опубліковано 24 тра 2023
- I found this Motorola DCT170 cable TV box recently.
Time to crack it open and discover some of its secrets.
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This isn't the only way to do it.
It's probably not the best way to do it.
But it's how I did it. - Наука та технологія
I keep the wound wires from these for building scrap FM radios. I just like building them and teach my nieces to build them. (5 siblings who had 12 kids and not a single boy except my son.) I just copied FM radio kits and found the parts scrapping other devices. These things are a good source of the wound wire inductors, crystals and resistors.
Great teardown. And a nice little project box, too.
Lots of quality parts inside and a project box as a bonus. Never pass up these little cable and router boxes.
I waiting for a tea review. We've had beer and coffee but can't remember a cup of tea. We need a balanced drinks review process. 😂😅😊
Lol.....a nice strong Assam cuppa...mmm ;-)
SRAM is probably stream cache, decoding is in the CPU with it's dedicated SDRAM and the bootloader and code flash.
Edit: The SRAM since it's only 256kB could be authorization and decryption codes. Having the battery backup could be to protect the contents of the SRAM.
That NXP part is almost guaranteed to be a powerpc processor. They really, REALLY loved that architecture at the time. That header on the side also match the number of pins used in their "low" pincount version of the COP interface :)
Another interesting vid
Don’t forget and keep your rubber feet for recycling on another project
That was cool... nothing like a nice teardown to start a Saturday of overtime at work. I open a lot of these up with the hope that I can repurpose the SOC but that always works out as "too complicated", even if I CAN find a datasheet... but you can often get a decent power supply out of them at least. All those (populated and unpopulated) headers round the digital parts.... I wonder if there's JTAG?
Thanks for the very interesting video tear down!
I love these teardowns because of your knowledge on the subject. Alps make the pots and Analog control sticks for videogame controllers.
Was that thing pulled from the Krusty crab? Thanks for the tear down. Nice to see what's inside
As to video compression, the customer bandwidth requirements are getting crazy. Where I work, we currently supply 1, 2, 5 and 10 GIG via FTTP to residential customers.
Crazy, who'd ever thunk?
I think that black five pin box is the SAW filter you mentioned as often associated with those chips, not a transformer. Betcha if you break it open you’ll find a little glass slab with quartz slivers glued to its edges.
That’s all I’ve got. I used to have a bunch of Motorola catalogs that could have identified that chip but I gave them all away when my eyes went bad.
Well that's not gun'a buff out 😆
The op-amps over at the power section are likely error amplifiers.
I'd hang on to those diodes, and x-tals.
Cool vid, thanks.
;)
Those receivers had the ability to decode mpeg2, but not mpeg4.
They also had a subscription system, the base channels worked fine without paying, but all the premium channels needed to be authorized. I presume there was some kind of unidirectional provisioning on them to allow them to get "those premium sports/movie" channels.
🍻
I think the auth data gets sent about every half hour or so. It's all about encryption. There are keys which need to be validated and they somehow send the needed keys to subscribed devices in a protected manner. The provisioning data also contains the mappings from virtual channel numbers to RF channel and subcarrier IDs.
the battery is likely powering some memory where the decryption keys are stored. Motorola (and its predecessors) loved to do it that way instead of using non volatile storage, and it also meant that when the battery died in 10 or so years after manufacture the box would be dead unless it is serviced and the keys installed.
Similarly, the unknown motorola chip in the vented can is possibly the decryption chip - there's an interesting video about one person's reverse engineering of a much older moto cable box here ua-cam.com/video/lhbSD1Jba0Q/v-deo.html
you might have been on the right path with the conexant CXP chip, as they were involved with cable TV / video processing and a quick google says NXP bought that business unit from them
That's a good probability.
I dont know to much about compression and video formats but i would have thought AVI would be better than HEVC. I heard Video cards are building in better Video compression for Streming.
Nice tear down - any of those chips/components worth a desolder? 👍😀
I always keep the ferrite toroids haha
Maybe some of the power supply components.
The rest seems pretty specialist.
Just love a tear down. I wonder if the processor is part of an early Android OS for the software to use the box.
I dont think they use android. That box seems way to old for running android. Probably runs a lightweight linux kernel and a oem os. Or some simple os. I bet that cpu is powerpc and not arm or mips. Powerpc seems relevant for that time. I have lots of old settopboxes from the same era use lightweight linux or simple os. And they where based on mips or powerpc
But where are the spy components that listen to you and record your every move?
That's done on the server side.
Where is the Conditional Access Module?
I assume any of that stuff is done in the main processor.
Does it have the spyware camera in it?
There's no camera in this old thing.
Well these old things did not have them yet because people actually respected privacy and had a brain to respect that, but nowadays everything does spy on you because some people dont have the brain power to think ab privacy