That C1 is the same exact C1 cap used in some of my newer "stock condition" analog boards, all with factory hot-glue applied:
630-0102-E
661-0462
And here is an unmodified analog board that shipped with the Mac 128k, dated 1983, with an older version C1 and no hot glue (but unlike some other early Mac 128k analog boards, this C1 is non-polarized, high-frequency, and rated at 100V -- a cap selection not prone to failure like the inferior polarized 25~35V rated C1 caps):
630-0102
If you do ever wish to swap out C1, "Metallized Polypropylene" is a replacement that will probably outlive you:
http://spreadsheets.google.com/ccc?key=0AnmQLg8d1xThcE96S1Z0S3oxOUFiMkJEYy1nNzNuZEE&hl=en
With regard to caps and hot glue, my company typically applies hot glue to electrolytic caps that are more than 1.5cm in height, especially on some of our truck alarms that will be used in environments with above average vibration. And while there is no vibration in the Mac 128k or 512k or Plus, Apple clearly found it important to apply hot glue on the tall caps on latter analog boards (noting once again that the oldest analog boards did not have the hot glue). It could have been due to Apple having later conducted vibration tests at the factory to simulate the jolts products would receive during shipping/handling. The hot glue is there to keep the two leads from the cap from breaking or otherwise detaching from the cap body.
630-0102-E
661-0462
And here is an unmodified analog board that shipped with the Mac 128k, dated 1983, with an older version C1 and no hot glue (but unlike some other early Mac 128k analog boards, this C1 is non-polarized, high-frequency, and rated at 100V -- a cap selection not prone to failure like the inferior polarized 25~35V rated C1 caps):
630-0102
If you do ever wish to swap out C1, "Metallized Polypropylene" is a replacement that will probably outlive you:
http://spreadsheets.google.com/ccc?key=0AnmQLg8d1xThcE96S1Z0S3oxOUFiMkJEYy1nNzNuZEE&hl=en
With regard to caps and hot glue, my company typically applies hot glue to electrolytic caps that are more than 1.5cm in height, especially on some of our truck alarms that will be used in environments with above average vibration. And while there is no vibration in the Mac 128k or 512k or Plus, Apple clearly found it important to apply hot glue on the tall caps on latter analog boards (noting once again that the oldest analog boards did not have the hot glue). It could have been due to Apple having later conducted vibration tests at the factory to simulate the jolts products would receive during shipping/handling. The hot glue is there to keep the two leads from the cap from breaking or otherwise detaching from the cap body.