Here is a link to  what you need

how to replace the apw8

https://support.bitmain.com/hc/en-us/articles/360013898033-How-to-detach-APW8-PSU-from-DR5-S11-S15-T15

https://support.bitmain.com/hc/en-us/articles/900000067286-APW8-16-32V-20-04V-EMC


this is the psu needed for your gear.

https://shop.bitmain.com/product/detail?pid=00020190418172319945PvKR86Kg0685



now it could be  the psu is not bad and there is a short in your hash boards.

if you have a working s15 or t15  you can swap the psu to the gear that has dead psu.

if the gear works you may just need to buy some psu's

lightfoot is very good at repairs he may have some other hints for you.

good luck.