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

[klx300r]

So wanting to replace my old and trusty original A4000 PSU with A4000 ATX PSU power adapter I purchased a micro-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 full 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 -+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?&^! :-D  :-P ..how come this kinda luck never happens when I buy a lottery ticket  ;-)  :roll:

[klx300r]

Interesting as I had the same thing happen when I used one of their adaptors on my A3000.  Unfortunately, not only did it not work, but now when I plug in the OLD working original adaptor my 3000 will not boot with that one either.
Dead in the water and I don't know why. (And yes it worked just fine until I tried the adaptor.)

So not sure if the adaptor was the issue or the power supply I tried but one of the 2 appears to have blown my 3000 and I am quite sad...

 

You cannot use the AmigaKit adapter with a modern ATX power supply on an A3000, it won't work.  Modern ATX power supplies do not provide the -5V line that the A3000 requires, and the don't provide the tick signal (though the jumper can be changed to use the internal vsync instead).   I had this confirmed from AmigaKit when I was looking to replace the PSU in one of my A3000's.  I couldn't source a good ATX PSU with the -5V line so I just went with Ian Stedman's ATX adapter, which has been working fine for quite a while now.

Hopefully someone didn't think they could interchange a +5V line for the missing -5V line on the adapter.

yup mine thankfully still starts up with original PSU

[klx300r]

http://ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/amiga_power_supplies.html#ATXPSU

Has good info on power supplies.

My A4000 with original PS has a tick signal out. I do not know if J104 selects this as external cpu signal or not.
I would check this jumper to see if it is set to internal.

The A4000 PSU doesn't provide a tick signal like with the A2000 and A3000.  The power connector has 6 pins, +5V, -12V, +12V, Power Good, and 2 GND's. 

J104 is the CPU clock source.  This has to be set properly if you have an accelerator card in the CPU slot.

I've got a CSMKIII in my A4000 so I'm assuming that J104 jumper is properly set as she's been working great up to this power adapter issue

[klx300r]

yup mine thankfully still starts up with original PSU

Oh, that's good!   I would try to find an ATX power supply where the blue line for -12V is more in the range of -11.8V to -12.2V.  The -11.32V your getting there may be too low for your A4000.

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.