uniserver said:

when you removed all the caps, did you wash the board in hot soapy water scrubbing it well,  then giving a hot water rinse,

then a good blast off with an air compressor,   Chances are you still have cap goo causing you stability issues.

Click to expand...

I didn't give the board an overall scrub, just spot cleaning in areas where there was obviously some cap goo.

I have been suspecting that there's some goo underneath some of the ICs - I'll have to give the board a more thorough clean and see what that does.

Any notable difference between the filters you listed, besides unit price?

I think I remember seeing a thread where the alternative-solution filters were proclaimed to be just fine.