I’m doing the power supply check on my filter board and for the first minute I have it plugged in it holds 5.0 and
4.9V fine but then it begins to drop quickly to 3.4 V and then slows down but keeps dropping. Bad capacitor? I checked all the polarities and they seem fine. Any advice would be appreciated tried setting my power supply from 5v 9V and it’s the same issue regardless.
Just to make sure you’re not chasing a ghost, try replacing the battery in your meter first.
You might be using a wrong power supply. Should be 9V. Anything above that might cause your voltage regulators to overheat which can cause voltage drops.
Even with a steady 9V I get the same problem +/-5V for about a minute then everything begins to drop.
Do the regulators get hot? Anything else getting hot?
Have you measured the supply voltage when the drop occurs?
Regulators do not get hot, supply voltage seems to be consistent voltage drop seems to be around the fat catalytic caps or second voltage regulator though I don’t really know how to check if a cap is bad or not.