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The EIectronics Inside 29: Retro BBC Micro Teardown

 

 

My very first experience of computing was with one of these. I was probably 5 or 6 years old, in school, one per class of 30 children. Now I'm an adult, I have one! But of course, not to learn with, to tear down!

 

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  • Great episode David!

     

    When you said, "that is not very many ports for a computer of this era," I was about to yell, "turn it over!" The awesome amount of ports is why it failed FCC certifications, at first, in America.

     

    Careful with those larger electrolytics. The ions in the electrolyte stay mobile, causing the dielectric layer to build up a decent charge even without power applied. Enough so, they'll give you a good shock. So leaving it disconnected is a good idea, but after a while, they become dangerous again! A 100-100K resistor across their leads will make them safe.

     

    (FYI. The 1uF you poined out is probably a paper X2 cap. These are EMI filters and not necessary for operation. Film/paper caps nearly always fail open. Though, I still recommend replacing them.)

     

    I never saw inside of a BBC Micro before. One thing that caught my eye is the RF modulator. It looks like the same manufacturer (and maybe part number) that Sinclar used in the ZX-81!

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  • Great episode David!

     

    When you said, "that is not very many ports for a computer of this era," I was about to yell, "turn it over!" The awesome amount of ports is why it failed FCC certifications, at first, in America.

     

    Careful with those larger electrolytics. The ions in the electrolyte stay mobile, causing the dielectric layer to build up a decent charge even without power applied. Enough so, they'll give you a good shock. So leaving it disconnected is a good idea, but after a while, they become dangerous again! A 100-100K resistor across their leads will make them safe.

     

    (FYI. The 1uF you poined out is probably a paper X2 cap. These are EMI filters and not necessary for operation. Film/paper caps nearly always fail open. Though, I still recommend replacing them.)

     

    I never saw inside of a BBC Micro before. One thing that caught my eye is the RF modulator. It looks like the same manufacturer (and maybe part number) that Sinclar used in the ZX-81!

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  • in reply to baldengineer

    Thanks James, I am always weary of caps! It comes from years of bad decisions on checking if things are off or wired right. It's just safer to assume everything is trying to hurt you!

     

    I didn't know about the FCC issues with the machine, thanks for that!