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Re: Studio II schematics?

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  • erd_6502
    ... I have not opened the RF switchbox, if that s what you mean (the modulator would be built into the main board, under the RF shield). Its switch does turn
    Message 1 of 7 , May 1 12:42 PM
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      --- In cosmacelf@yahoogroups.com, "awasson2001" <andrew@l...> wrote:
      > Hi Ethan,
      > Have you checked the RCA modulator for a faulty switch or leaky cap,
      > etc..? If your Studio II is in fairly good shape, that's where I'd
      > look first.

      I have not opened the RF switchbox, if that's what you mean (the
      modulator would be built into the main board, under the RF shield).
      Its switch does turn the unit on and off, but I'm not going to swear
      that it's working perfectly.

      I'll start there; thanks for the tip.

      > I've got some Studio stuff coming this weekend (Sunday) including a
      > set of plans for extending it as a micro computer (sort of). It's
      > possible there's a set of schematics as well. I'll post whatevewr I
      find.

      Nice. I've heard of those plans and I've always wanted to see them.
      Can't wait.

      -ethan
    • awasson2001
      Ok, I ll get to the Studio II schematic in a minute but I have to say first... I really lucked out! I picked up a STG ELF-2K for a very good price from a chap
      Message 2 of 7 , May 1 9:07 PM
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        Ok,
        I'll get to the Studio II schematic in a minute but I have to say
        first...

        I really lucked out!

        I picked up a STG ELF-2K for a very good price from a chap that built
        it recently with an old ceramic CDP1802 CD. As it turns out, I could
        not have purchased the parts & partial kit for less than what I paid.

        It had nothing to do with me being clever. I was all but ready to go
        to Bob's site and order the parts when I saw this one on ebay and bid
        what I figured was too low but... What the heck. I didn't even stay up
        to watch the end of the auction. I didn't think I stood a chance of
        getting it. Low and behold, I got it. It wasn't me it was just dumb
        luck and so here I have sitting in front of me an STG Elf2K and it's
        just so darn cool!

        It's kinda similar to my Quest Elf and also a little similar to the
        Elf II I used to have but I know deep inside of it there's a bunch of
        more Ram, Expansion and a serial port. The fellow who built it also
        burned a ROM with ELF 2K Ver23 (I think?). I've got some learning to do.

        Now, I have to get the STG1861 replacement and of course the COSMAC
        Elf 2000 disk (CompactFlash), UART, Clock and Non-Volatile RAM
        expansion option. (I wish I had this while you were beta testing it.)
        I'm already working on the HEX Keypad which I'll add
        shortly.

        Bob, I've been drooling over the Elf2K since I first saw it on your
        site back in December but to actually switch it on is another story.
        This puppy rocks!

        *****************
        * RCA STUDIO II *
        *****************

        Ethan,
        I have a diagram of the Studio II. It isn't detailed and really is a
        block diagram. I'll scan it when I have a moment and upload it. It's
        part of that document I mentioned earlier about Converting a studio
        into a microcomputer.

        This is really neat document from March 3 1979 and I will scan it in
        entirety as soon as I can so that it can be added to the site.

        Cheers,
        Andrew




        --- In cosmacelf@yahoogroups.com, "erd_6502" <erd_6502@y...> wrote:
        > --- In cosmacelf@yahoogroups.com, "awasson2001" <andrew@l...> wrote:
        > > Hi Ethan,
        > > Have you checked the RCA modulator for a faulty switch or leaky
        cap,
        > > etc..? If your Studio II is in fairly good shape, that's where I'd
        > > look first.
        >
        > I have not opened the RF switchbox, if that's what you mean (the
        > modulator would be built into the main board, under the RF shield).
        > Its switch does turn the unit on and off, but I'm not going to swear
        > that it's working perfectly.
        >
        > I'll start there; thanks for the tip.
        >
        > > I've got some Studio stuff coming this weekend (Sunday) including
        a
        > > set of plans for extending it as a micro computer (sort of). It's
        > > possible there's a set of schematics as well. I'll post whatevewr
        I
        > find.
        >
        > Nice. I've heard of those plans and I've always wanted to see
        them.
        > Can't wait.
        >
        > -ethan
      • Robert Armstrong
        ... back in December but to actually switch ... Thanks! Be sure and download the manual http://www.sparetimegizmos.com/Downloads/Elf2k.pdf BTW the current
        Message 3 of 7 , May 1 9:45 PM
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          >Bob, I've been drooling over the Elf2K since I first saw it on your site
          back in December but to actually switch
          >it on is another story. This puppy rocks!

          Thanks! Be sure and download the manual

          http://www.sparetimegizmos.com/Downloads/Elf2k.pdf

          BTW the current firmware version is v60. If you have an EPROM programmer
          you might want to update it.

          Bob
        • erd_6502
          I forget if I ve already asked here or not, but does anyone have schematics for the RCA Studio II? I have one here that responds in a reasonable fashion to
          Message 4 of 7 , Jun 18, 2005
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            I forget if I've already asked here or not, but does anyone have
            schematics for the RCA Studio II? I have one here that responds in a
            reasonable fashion to button pushing in terms of beeps and noises, but
            with absolutely no picture. Scoping the video area seems to indicate
            that the TA-whatever Pixie chip is emitting reasonable signal for
            video, but nothing seems to be coming out on the TV screen.

            To ensure maximum signal compatibility, I am using an old B&W TV,
            tuned to the right channel, etc.

            So... if I suspect the problem is in the (onboard) RF modulator, does
            anyone have a schematic so I can trace out where the signal stops
            being passed along? There's a CA3086 5-NPN DIP in there that I'm
            currently somewhat suspicious of, if for no other reason, the other
            components in there look somewhat robust (1/4 W resistors and ceramic
            disc capacitors and a few coils).

            Thanks for any pointers to info,

            -ethan
          • sbirdasn
            You might also try tapping into the pixie video at the summing node resistors by the TA-xxxx chip and put it directly into a video input to see if you get a
            Message 5 of 7 , Jun 18, 2005
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              You might also try tapping into the pixie video at the summing node
              resistors by the TA-xxxx chip and put it directly into a video input
              to see if you get a picture too. The timing shouldn't be so far off
              that any normal TV with video line inputs can at least display a
              picture.

              Unfortunately, modulator circuits tend to not get documented so well,
              so you may have to tough it out and trace it on your own.

              Also, VIPER V1I6 only has a block diagram.
              :(

              Tony.

              --- In cosmacelf@yahoogroups.com, "erd_6502" <erd_6502@y...> wrote:
              > I forget if I've already asked here or not, but does anyone have
              > schematics for the RCA Studio II? I have one here that responds in
              a
              > reasonable fashion to button pushing in terms of beeps and noises,
              but
              > with absolutely no picture. Scoping the video area seems to
              indicate
              > that the TA-whatever Pixie chip is emitting reasonable signal for
              > video, but nothing seems to be coming out on the TV screen.
              >
              > To ensure maximum signal compatibility, I am using an old B&W TV,
              > tuned to the right channel, etc.
              >
              > So... if I suspect the problem is in the (onboard) RF modulator,
              does
              > anyone have a schematic so I can trace out where the signal stops
              > being passed along? There's a CA3086 5-NPN DIP in there that I'm
              > currently somewhat suspicious of, if for no other reason, the other
              > components in there look somewhat robust (1/4 W resistors and
              ceramic
              > disc capacitors and a few coils).
              >
              > Thanks for any pointers to info,
              >
              > -ethan
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