Module Tester- barely audible

Thanks in advance for any support here, I know this is a discontinued precut that I built but was looking for some help.
I built the module tester and initially tested the audio connected to speakers and seemed to be working fine. I then, stupidly, connected the ribbon cable backwards and it blew out the LCD. I replaced the LCD and all other functions now work except for the CV and Audio out.
The audio out is extremely low, I can hear something if I hook it up to my mixer and turn the level way up.
I’ve replaced one by one all the ICs and tested after each one, still nothing and not sure where to look next.
Thanks again!

Do you get the correct supply voltages (-12V and +12V)?

Thanks for the quick reply, I had ordered a new power supply to confirm that wasn’t the issue. could you let me know which pins to test on the module tester? Im still confused with this sort of troubleshooting… I have a multimeter, DC, AC, etc… so to be a bother. If you could let me know and I followed along with the schematic, maybe some of this would make sense.

Thanks again!

After testing, Im not getting -12V (getting .22V instead) and the LM4040 is not showing reference value of 4.096. Ive replaced the LM4040 and the LM2990 to no effect. Not sure where to check next.
Thanks for any help at all!

Are you using the right power supply?

Yeah, stupid mistake on my part… I didn’t read the fine print on the previous one I was using and it was AC --> DC I have the right one now and al is good! For anyone else who might stumble on this post, heres what I am using and works: https://www.amazon.com/gp/product/B00B8861T2/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

Thanks Olivier!!