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 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?&^! :-D ..how come this kinda luck never happens when I buy a lottery ticket ;-) :roll:

 

[salaxi54]

Have you read Ian Stedmans' guide? http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/amiga_power_supplies.html
Wiring details for A4000/A4000TThe A4000 desktop machine is not too difficult to wire a new PSU upto, it only has 6 wires.
Importantly, the A4000 requires the ATXÂ PWR_OK signal to function, if you do not connect this, it will not work.

Note: PWR_GOOD=PWR_OK. A logic 1 level indicates that the PSU is operating normally.

He's got a pinout list after that.

 

[klx300r]

yup I have but still shaking my head why 2 new(er) PSU's I tried won't work with the adapter I have when seems adapter is working ok ???

 

[klx300r]

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.