No -5v on the filter board

Dear All,

I have an issues with my powersuply.
I tested the voltages with my multimeter, all +5v points are correct, the -v5 point however are not.

anyone able to help?

Thanks a million!

I can’t see from your picture if C1’s polarity is correct.

thanks for the fast reply i’ve adde a new picture with c1 polarity, i think its ok like this.

also i noticed that the 7905 feels warmer then its 7805 variant. maybe i fried that component?

Whats the input voltage oft the 7905?

Which pins should be the input of the 7905?

nvm found it on the datasheets,

the input for the 7905 is only 3.30v

So you should check the inverter circuit around IC1. Any bad solder joints? Maybe IC1 is defective. Those things are pretty fragile. A short on its output will destroy it pretty quickly.

On a correct board, the input voltage on the 7905 should be slightly below -9V (in case you are using a 9V supply)

measured between GND and Vout on IC1 and it reads -3.30 aswell

anything i can try next?

As I said, the inverter circuit around IC1 is probably defective. Try re-heating all solder joints in that area. If it doesnt work, try swapping the IC1 for a new one.

Attention , if there was a short on the -5V rail , you damage the new one also .
Remove all IC’s , than measure with an OHMMETER from Ground to -5Volt . Than insert the new one. Now the -5Volt there ??
Greets
Andre’