 | | Aaargh. L272 IC needed.
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We've run into a little bit of a snag with Operation DCC. Mario has done up the TMW5 Booster board, but we're missing an IC for the decoder unit. It's the SGS Thompson L272, a dual power op amp in a DIP package. We need the L272M, the eight pin DIP (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) I'm no help on that... but I'm anxious to learn more about the project's progress when you guys have time to talk about it. I spent a bit of time talking with Tom Cook while at the fest, he showed me his installations. He's using a (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Two things discouraged us from using something like the DN140 (IIRC) he used. There's a shortage of them, and every Southern Ontario train dealer has them on back order, AND everyone seems to overvalue their price. As a result, each DCC (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) I wonder if there is a way to cheat? That is, use track connectors to jumper the power to the unpowered rail. I have to take a close look at a turnout when I get home this weekend to make sure doing that doesn't cause shorts but I don't think (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) IIRC there are pads on the bottom of the frog where jumper wires that could be soldered onto. But the track connectors idea is very doable, it should work great. (...) If you wanted to start a side business of selling integrated decoder plus (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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Having built a number of non-DCC reversing loops, I can tell you it's pretty straightforward to jumper using track power leads, as Larry suggests. It can get pricey if you're buying them from S@H, but I expect most trainheads have more leads and (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Not sure I agree. I left traditional MR because I prefer the resiliency of the brick and don't have a lot of interest in soldering any more... (...) I think this is a valid argument in the general case but fails in my case for two reasons: (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) One small savings possible is that you do NOT need to jumper the outside rails! (think about it, they run through) So you can get away with a track power connector that connects to just the two inner rails... depending on whether you have more (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Or connect one half of the connector to each rail in question (provided they are close enough, of course), and take an additional short Lego wire and "short" it - that is, connect it to itself at a 90-degree angle - and clip it on top of the (...) (23 years ago, 17-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Hi Calum, have you found the chip yet? OpAmp in 8 pin dip is a common thing, you'll probably be able to find a equivalent of that chip that will do the job. Bring the spec of the chip with you to a store so you can check the spec in databook (...) (23 years ago, 19-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Actually yes. Among fighting corporate Real Estate this morning, demonstrating my two fisted project management skills, and the usual critical nonurgent at the office, we also managed to hunt down a source of L272M's at a component firm. With (...) (23 years ago, 19-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Yes..... it looks like DCC is a closer realization at (or with) rtlToronto than was possible...Awesome....I still like that DCC joystick/controller for $150... it looked very neat (I saw it at my local hobby shop).... but I really don't want (...) (23 years ago, 19-Jul-01, to lugnet.org.ca.rtltoronto)
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| | Re: Aaargh. L272 IC needed.
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(...) Well, the first rtlToronto DCC will be switchable. Here's the deal from the enduser standpoint: a) your motor pack has to be modified to allow for the DCC decoder to drive it. This means installing a small switch inside it and some extra (...) (23 years ago, 19-Jul-01, to lugnet.org.ca.rtltoronto)
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