need help my A4000 won't start with new A4000 ATX PSU adapter

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.

atx power supplies are problematic when you try to run them with Amiga. That is why I have made extensive research before getting myself an ATX psu for my A4000T.

The one I use is this:

https://www.amazon.com/Seasonic-SS-520 ... inum-ATX12V/dp/B009VV56TO

This is the best power supply for low ripples on the 12v rail.

Ripple on the 12V rail is of no real concern to an Amiga, and certainly won't stop the PSU turning on. All the Amiga's logic runs off the 5V rail, which is where you want the low ripple.

As for the original issue from a year ago, those adaptors are pretty simple - there's not a lot that can go wrong with them. If it's turning on the PSU without being connected to the A4000, then it's doing its limited job correctly. The issue is between the PSU and the A4000 then, and as pointed out above, ATX PSUs aren't particularly well suited to Amiga use. The most common issue is that it doesn't draw enough current to regulate properly, in which case it should immediately shut down (though some poor quality units will continue to output out-of-spec power). But that's not the case if the PSU turns on with no load. In this case it's probably more likely to be an imbalance in the load, where the output of the PSU isn't connected how it expects. Perhaps some of the ground or power rail lines aren't connected to the rest, confusing it, or perhaps it requires the 12V load to be similar to or greater than the 5V load. This could be the "sense" issue mentioned.

Sorry. I meant the 5v rail

so to follow up I had zero luck with the adapter and ended up trying 3 ATX PSU's and one of them snap, crackled and sparked literally leaving me screaming and in shock as I feared my beloved CS-MKIII and secondly everything else in my A4000 was fried....so luckily that wasn't the case and I ended up recapping my original PSU and all works great except now the sound is very low on both channels which I expect has something to do with fried ATX PSU and that adapter as sound was working fine before that........one of these days I'll find the space and time to take her apart and trouble shoot sound issue but it's been a while I'm still shell shocked and relieved nothing damaged..other than sound that is

@328gts
I guess you haven't recapped your A4000, it's a common fault of the A4000 with the sound caps dying.

@khayoz

100% recapped before the mess with that ATX adapter happened. Since then I also recapped my original PSU

Did the sound work 100% before you started testing different PSUs?
Is the new (sound)caps mounted wrong way as the Commodore original caps?

I think the silkscreen on the A4000 is wrong, and Commodore placed the caps the right way, but Amigans have discussed this to death, so don't quote me on that. ;)

@khayoz

yes it did & not sure if caps were installed in opposite direction or not but thats a debate in itself....I do know that the entire MB caps were all replaced a few years ago so even if the bi-directional caps theory is correct or not I doubt they would go bad that fast?..though I'll find out once I strip my A4000 down & let you know