I have 826E16-R1200 with 1200 Watt power supply called PWS-1K21P-1R, I now want to upgrade my chassis with your 1400 Watt super quiet power supply called PWS-1K41P-SQ , I checked and the power supply dimensions are the same, Is it possible to use PWS-1K41P-SQ in this chassis?
No, that will not be possible.
The PWS-1K41P-SQ (hot swap)connector is wider than that of the PWS-1K21P-1R, so these power supply modules are not exchangeable