Predicta Holiday restoration

[wa2ise]

Originally Posted by bandersen

There's a 47K and 4.7K in series between pins one and 2 for a total of 51.7K. I measured 70.7K.

Between pins 2 and 7 I should have 3300pF but measured around 4300pF.

Seems to me those are pretty far off and I should replace this network. I'll pop out K2 next and see how it measures up.

These things were not that accurate when they were manufactured back in the day. The resistance may have increased some over they years, but it's hard to figure out how the capacitance went up (unless leakage is fooling your test equipment, but that equipment likely also has a leakage test). Replacing them with modern parts certainly won't hurt, and may fix a problem if one of these modules did get too far out of spec.