Op-amp test question

[patricks]

Hi everyone!

I rescued some op-amps from an old mixer a few years ago, and finally have gotten around to checking them out after they've been rattling around in my parts bags for years.
I've tried two methods, one from this forum: https://www.diystompboxes.com/smfforum/index.php?topic=63394.0#msg499683
and another from here: https://circuitdigest.com/forums/analog-electronics/how-check-if-my-op-amp-damaged

The first I tried were a couple of RC4558, using 9V as Vcc, and based on the "quick and dirty tester" from this forum all checked out (yay, more mojo parts maybe!). Following the method on the other forum I got Vcc at each of the outputs no matter how the inverting and non-inverting inputs were connected.

Does this more likely mean I've got an internal short, or that the method on the other forum isn't quite right?
I'm reading up more on the Geofex "when good op amps go bad" article as well

Cheers, Pat

[antonis]

P.S.
I should have modded for dual op-amp, but I became infected with laziness due to deadastronaut gaggling..

[patricks]

Oh cool! Thank you - I can modify for a dual op amp, and if I'm feeling ambitious I'll try adding in connection points to adjust for different pinouts

[patricks]

Modified the first post to include the correct link to the post I found in this forum.
It's similar to your schematic, Antonis, but without the diodes to prevent voltage pull-apart and feedback resistors