68kMLA Classic Interface

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Colour Classic analog board issues
Posted by: Jon183 on 2018-01-04 06:23:43 Hi everyone, first of all, system is totally lifeless, no sounds at all when trying to power it on, I haven't measured anything yet because I need a new 9v battery for my multimeter, any idea what to around the burnt areas (picture 2) and in general? Planning to replace every electrolytic cap also. Found this topic which mentions replacing horrible looking RF11: https://www.thinkclassic.org/viewtopic.php?id=202&p=2 RF11 - 390 Ohm, 5% Tolerance 2 Watt RL62 - 47 Ohm, 5% Tolerance 2 Watt Is there any other methods of repair I should use instead of exact replacement besides from moving from 1 watt to 2 watt resistors? What should I do about zener diodes?
Posted by: techknight on 2018-01-04 08:40:02 and you know the logic board is good? the analog board wont turn on unless the logic board sends the signal from its EGRET.
Posted by: Jon183 on 2018-01-04 17:31:53 So it can still behave totally dead due to logic board? Its been washed, pads cleaned and old caps gone but no recap yet, waiting for caps in post. Board looks great though.
Posted by: Jon183 on 2018-01-05 02:58:01 I hope it not turning on wasn't the logic board (not really), analog board is already out, decided to recap it and replace some other stuff, gunk was spotted under some caps. The bad looking resistor fell apart when i tried to remove it, I do know its values though.
Posted by: techknight on 2018-01-05 07:24:32 Yes the logic board WILL stop the unit from powering on, but some analog boards need caps by now anyways so.
Posted by: IlikeTech on 2018-01-05 09:26:37 If you take out the logic board and turn it on, the board should come on and the hard drive should spin up.
Posted by: techknight on 2018-01-05 09:37:36 Not always. I have had boards that wouldn't.
Posted by: Jon183 on 2018-01-05 20:43:40 Fuse was blown, replaced it.
Posted by: Jon183 on 2018-01-12 08:47:46 Anyone know the value for DL21? I know DL22 is bzx85c18, accidentally broke DL21 while removing it.
Posted by: olwilli on 2018-01-13 07:46:21 Anyone know the value for DL21? I know DL22 is bzx85c18, accidentally broke DL21 while removing it. They are the same - you can use BZX85C18 for DL21 and DL22
Posted by: Jon183 on 2018-01-13 07:50:09 Thanks, Ill order all the new parts soon.
Posted by: superjer2000 on 2020-05-17 18:24:55 Anyone know the value for DL21? I know DL22 is bzx85c18, accidentally broke DL21 while removing it. They are the same - you can use BZX85C18 for DL21 and DL22 I recognize I'm bringing this thread back from the dead - I'm just recapping my colour classics and on my unit I don't have 2x BZX85C18 but instead 2x 1N5931B. Does anybody know if the 1N5913B was a change Apple made in later boards (it's a beefier part 3W vs 1.3w) or were people just recommending the BZX85C18 because they thought the specs were the same? The analog board is still a bit toasty there so I'm going to replace the two diodes even though the board worked fine but I'm going to get them off the board a bit to help with cooling.
Posted by: Franklinstein on 2020-05-18 01:29:26 There were four revisions for the CC's analog board (A through D), though usually in the States you only encounter the Rev. A or possibly B in the CC; the Rev. C and D were usually in CC II/P275 units sold elsewhere in the world. There's a thread here about modifying early Rev. A boards to get them to safely output VGA by replacing a number of components. However later revision boards have different component values or things populated/depopulated compared to the earlier boards which makes following the mod guide tricky. First order of business is to figure out which revision analog board you have. It should be on the bottom; you have to remove the shield tray to see it. It'll be something like 830-0360-X where X is your revision. Apparently those diodes run really hot regardless, so as soon as you install new ones they'll start to darken. It doesn't seem to negatively affect them.
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