This is the modified version of the LM 741 Op Amp tester in the older Post:
I’ll draw it out correctly, but basically it’s twice the above circuit with pin 7 Vcc changed to pin 8, and the LM358 amps are pins 2-;3+;1 out; 6-;5+; 7 out with pin 4 gnd the same. I changed 10k to 8.2k as I have more of them:
The plots at the cap – charging/discharging – and LED show why the LED blinks with square wave pulses. Now build the other side the same for pins 5,6,7.
I have used it to test the original M5219P tone amp in the Technics V1X that I thought had a duff side until I found the link cable pin short, but it’s fine.
It’s a handy tester to have if you work on stereo amps with tone control stage op amps in them.