So wanting to replace my old and trusty original A4000 PSU with A4000 ATX PSU power adapter I purchased a micor-ATX psu that fits nicely into the A4000 PSU chasis BUT....

1-tried connecting micro-ATX and nothing..PSU not starting at all nor A4000 so tried another dull size ATX PSU and same thing
2- contacted Amigakit and they told me it was some 'sense' thing with newer PSU's but I had my suspicions
3- tried starting the PSU without connecting to A4000 and voila PSU started up no problem with following voltage readings:

Grey (what you call purple)-+5.21v
Blue--11.32v
Yellow-+ 12.14v
Red-+5.23v
4- let Amigakit know and they said these readings were fine and adapter was working ok but offered no help as to why it wasn't powering on my A4000

So long story over I turn this mystery over to my fellow amigans and hopefully I'm not the only one in the world this has happened too?&^! ..how come this kinda luck never happens when I buy a lottery ticket

Those voltage measures are from the adapter and not from the PSU right?
If not check the adapter for continuity.

Does it still boot up with the old/original PSU?

Edit:Read your post on Amiga.org and with "Outlawal2"s answear I can can only suggest that the adapter is faulty(wrong wiring).

I guess that Amigakit(nothing against them, love their continous Amiga support) is going to have to get their repairshop busy for selling adapters that kill their customers jewels.

Have you tried to test the switch in amiga4000?
Test to connect without connect the switch cables to 4000 switch and make a bridge connection between the two cable switch .
Sorry for my poor english dont know if you understand .

@khayoz

yes they are from new microATX PSU hooked up to adpater and yes my original (old) PSU works fine still

@ AlicPPC

switch works fine with both original and adapter

Update:

got around to try a full sized ATX PSU tonight and readings as follows when not connected to anything again:

Grey -+5.11v
Blue--11.52v
Yellow-+ 12.21v
Red-+5.11v

and yet again like the micro-ATX PSU my A4000 won't boot up at all. Tried attaching an old 'real' hard drive to see if some extra load draw would kick it up but same thing.