68kMLA Classic Interface

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Chip came off Classic II board and took a pad with it.
Posted by: Jon183 on 2017-11-12 02:12:18 Hi everyone, I was cleaning the Macintosh Classic II revision 1 logic board with a q-tip soaked in isopropyl alcohol and a chip I was cleaning came off the board, it read 136x 78l08a and I believe it is a texas instruments chip. I looked up the last part and it came up with voltage regulators. Could I find a replacement somewhere (still have original), and what should I do about the missing pad?
Posted by: Bolle on 2017-11-12 05:06:00 You are lucky, pin 4 is NC. You can use any 78L08 in SO-8 package. Those are still made today so I would just get a new one and not bother with the old one that might be dead due to cap goo anyways. https://www.digikey.com/product-detail/en/stmicroelectronics/L78L08ACD13TR/497-1189-1-ND/586189 this one should do it. You might want to check the audio amplifier right next to it as well as the solder points do not look too good on that one as well.
Posted by: Jon183 on 2017-11-12 06:00:30 You are lucky, pin 4 is NC. You can use any 78L08 in SO-8 package. Those are still made today so I would just get a new one and not bother with the old one that might be dead due to cap goo anyways. https://www.digikey.com/product-detail/en/stmicroelectronics/L78L08ACD13TR/497-1189-1-ND/586189 this one should do it. You might want to check the audio amplifier right next to it as well as the solder points do not look too good on that one as well. Thanks, due to shipping costs im going to use element14.
Posted by: Jon183 on 2017-11-12 06:26:06 http://au.element14.com/on-semiconductor/mc78l08acdg/ic-v-reg-8-0v-smd-78l08-soic8/dp/1211120 Would this be suitable?
Posted by: Bolle on 2017-11-12 06:31:47 Yes.
Posted by: jack on 2017-11-18 17:34:52 Saw this thread now... makes the other one make sense 🙂
Posted by: Jon183 on 2017-11-26 22:14:50 The voltage regulator chip came today. I installed it and put the system back together. The analog board has 3 new caps and I have to wait for the rest as element14 takes far longer than RS and charges for shipping too, not sure why. The logic board has been recapped, washed, swabbed with alcohol and q-tips, and has a new voltage regulator for U2. First picture is the final appearance of the logic board. The system works now, it boots from the HDD. It was set for 110v but it now works with 240v. Thanks for all the help everyone. View attachment 21290 View attachment 21291
Posted by: jack on 2017-11-27 05:33:39 Congrats! Always exciting to have one more working system!
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