68kMLA Classic Interface

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Color Classic no power issue debunked!
Posted by: uniserver on 2015-06-13 17:36:32
if that Y2 is rotted off, then your cc is going not not only need it but a lot more, including a re-cap.

the nice thing about that Y2 is, its the same on quite a few other 68k mac boards.
Posted by: mraroid on 2015-06-14 12:11:31
OK .  Thanks.  I have replaced this board with a Color Classic II board.  I thought I would use my original color classic logic board to try to do a re cap my self.  That way, if I screw it up, I will still be running my color classic II board.

But I do not know what that part is, and if I can buy a new on on, say, Mouser or Allied electronics.

Can you tell me what it is and what I should search for?  It is the crystal right?

Thanks

jack
Posted by: dougg3 on 2015-06-14 12:50:07
It's definitely a crystal. The only identifying info I can find on mine is: "S3238E", which when I google brings up other threads including one you participated in over on AppleFritter. A thread over here indicates the SE/30 uses the same crystal, and according to schematics I've seen that crystal is 32.768 KHz. This is a very common frequency used for real-time clocks so it's no surprise that it's 32.768 KHz.

This will be a crystal you can find at any supplier. Just search for a through-hole 32.768 KHz crystal. You'll see plenty of results that look just like the original (cylindrical can, radial). The unfortunate thing is that I can't find anything about the original part number, so I don't know the details about the load capacitance of the crystal. Typically you're supposed to match the load capacitance to the circuit. You might just have to guess and hope it works (it will probably be fine).
Posted by: uniserver on 2015-06-15 00:10:47
the one on this se/30 parts board says (Y1) F39APAA  i think, its half rotted off, it was a battery explosion.
Posted by: uniserver on 2015-06-15 00:17:30
yup and unlike in this thread "https://68kmla.org/forums/index.php?/topic/24193-repairing-se30-battery-acid-damage-whats-on-d1-and-d2-and-crystal-speed/"

the Color Classic needs that Clock to the EGRET, or else it will not power up.
Posted by: elemenoh on 2019-07-14 15:41:58
While attempting dougg3's fix with the wire between the crystal and C56 I managed some spectacular feat of clumsiness and lost C56. I looked everywhere but it's in the land of left socks or some other mysterious locale.

Does anyone know the value for that cap or what I can sub with? I tried 10uf but that didn't seem to work. I'm still getting the static noise when the power switch is flipped but no chime on soft boot.

Here are a couple of photos of the board as it is.

IMG_7713.jpgIMG_7714.jpg
Posted by: elemenoh on 2019-07-23 16:44:34
Any advice on how I can fix my blunder mentioned above?
Posted by: AwkwardPotato on 2019-07-23 17:04:31
10uF is way too high for an oscillator circuit like this, try a 33pF cap.
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