128k Mac Analog Board - Help, I need to identify the parts. — #5

Post #5 by giolicious

Source Forum	68kMLA
Category	Troubleshooting
Post Date	Sat, 12 Nov 2011 - 04:58
Original URL	https://68kmla.org/bb/threads/128k-mac-analog-board-help-i-need-to-identify-the-parts.24118/

Post

My Analog Board photos:http://www.flickr.com/search/?q=analog&w=66071596%40N00&m=tags

My Analog Board Replacement Parts List, mostly capacitors (note there are two sheets):

https://docs.google.com/spreadsheet/ccc?key=0AnmQLg8d1xThcE96S1Z0S3oxOUFiMkJEYy1nNzNuZEE&hl=en_US#gid=0

For additional component info and repair details, I highly recommend this Larry Pina book:

http://www.amazon.com/gp/offer-listing/0672484528/ref=dp_olp_used?ie=UTF8&condition=used

What do you mean by "UPGRADING the Compact Mac Analog Board" ? Can i just use the original 128k parts for replacement?

via PM:

Thanks for your question.

The original parts used by Apple in the Macintosh 128k analog board of 1984 are not robust and they will fail over time. That is why even Apple itself "upgraded" those components to better parts in later editions of the compact Mac. The best of the original Mac analog boards was the Plus (the SE doesn't count because its analog board is very different). And my Google Docs component list equals or beats the components used on the Macintosh Plus.

All said, if you use the original Macintosh 128k components and specifications, you will experience the same failures as the original Mac 128k did. When that failure will occur will depend on usage. But since you likely won't use a Mac 128k as your main machine, you probably won't experience failure for a long time. However, I myself would prefer to put the best parts possible in the analog board, such that I never have to worry about doing that job again! And if you follow my replacement chart, you will accomplish just that.

I hope this helps.

Best wishes,

When you say "HF" (High Frequency) on your list, what do you mean by that? i was inquiring at a local electronics store here in my area but I don't see "HF" printed on the capacitors. How do i know if it's a HF cap?

One more thing. On your replacement part list for CR20 I noticed that it's physically different from the original part.

replacement part:

original part:

742928204-40.jpg.ace242f302ba6937d82a54759f76a313.jpg

My question is, how do I fit the new replacement part on the board?

via PM:

HF is High Frequency. All caps that are spec'd for HF will mention such on their datasheets. If a cap doesn't say it's HF, then it's a LF (low frequency) part. You need HF wherever I wrote HF in my list.

Usage of the diode is easy. Note the datasheet:

http://www.onsemi.com/pub_link/Collateral/MBR1035-D.PDF

Note that Pin 1 = Pin 4 electrically. You therefore can just cut off pin 1 and connect pin 3 to the PCB thru-hole, then screw-in the top section of the part to the heatsink on the analog board, as shown in my photos here:

http://www.flickr.com/photos/66071596@N00/347417433/lightbox/

(Noting that my photo shows a stock Apple analog board which I own, two of which are referenced in my Google Docs chart as "630-0102-E" & "661-0462".)

My comprehensive set of analog board shots are found here:

http://www.flickr.com/search/?w=66071596@N00&q=analog

Please let me know if this clarifies matters. If it does, and when you have time, you may wish to publicly report your efforts in a new thread, as I am sure such would be of great assistance to others too.

Best,