Where to purchase a DESKTOP Power supply unit.

Hi! there,

As a retired man who builds and repairs computers as a hobby, I prefer to use a desktop case with my system. The trouble with this is that I am finding it impossible to purchase a replacement Power Support Unit. As most of you will be aware, a Power Support Unit for a DESKTOP case measures only 120mm High x 85mm Wide x 156mm Long. This is because a normal DESKTOP case is only 5 1/2 inches deep. I have 'e' mailed numerous Power Support Unit suppliers, as well as computer warehouses, but it appears that they just cannot be bothered with such enquiries, and they either DO NOT reply to my enquiry, or they say that their power support units are as seen on their website. I find this rather contradictive as Power Supply Unit suppliers DO NOT put the overall measurements of all their power supply units on their websites. It is very annoying when you purchase a DESKTOP case you like, that you find it impossible to find a replacement Power Support Unit to fit that case. Any advice on how to rectify this problem would be very much appreciated.