Re: Tron: parts question

On Tue, 30 May 2000 solarfox@texas.net wrote:

> The LM3900 should be under "linear I.C.'s", then "comparators"... but
>of course, the Brainiacs at Radio Shack have managed to screw up their site
>so that you can only see page 1 of any product line; trying to go to any
>other page gives me a URL not found...

  Yes, the site is not great, but for me, its one benefit over
Digikey. is photos. At this point, I'm still learning what's what, and
what it looks like. =) At Digikey, I tend to get lost in all the spec.

> The phototransistor will only conduct when its base (B) is stimulated
>by light from the LED - so turning the LED on and off will control whatever
>circuit is connected to the phototransistor.

  Okay, I see it now.

> By the way - this whole circuit is not all that necessary. In fact, it
>has been known to take a perfectly working MCR-series game and stop it in
>its tracks by just deciding not to work one day. (Yes, I speak from
>experience. :) ) Personally, I'd suggest that you not even _bother_
>replacing U3 and U4 - just pull the bad ones out, then snip the purple wire
>at J4-15 to disconnect the RESET signal entirely.

  I will keep this in mind, if later it gives me trouble. This is my
first foray into repair, so I'm sure I'll cause enough trouble as it
is. =) I should have just replaced the pot, and then went from
there. But nooooo...I had to do it right, clean it all up, replace the
"maybe" bad parts. =)

> True... but on the other hand, it never hurts to have spares on hand,
>so if you're going to order them, I'd say you ought to order at least ten
>of each anyway. :)

  But the plan is to fix it right, and not screw anything up in the
process, and get it all right the first time, and have it work
flawlessly for as long as I have it. Isn't it? =)

  Thanks for all the help and info, that's why I love the list. =)

                                        Remy LeBeau

  The early bird gets the worm, but the second mouse gets the cheese.

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Received on Tue May 30 14:02:39 2000